Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

arXiv:1207.2757v1 [hep-ex] 11 Jul 2012

Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the

Tevatron

T. Aaltonen†_,12 _{V.M. Abazov}‡_,48 _{B. Abbott}‡_,112 _{B.S. Acharya}‡_,31 _{M. Adams}‡_,78_{T. Adams}‡_,74 _{G.D. Alexeev}‡_,48 G. Alkhazov‡_,52 _{A. Alton}‡a_,96 _{B. ´Alvarez Gonz´alez}†a_,57 _{G. Alverson}‡_,92 _{S. Amerio}†_,35 _{D. Amidei}†_,96 A. Anastassov†b_,76 _{A. Annovi}†_,34 _{J. Antos}†_,53 _{G. Apollinari}†_,76 _{J.A. Appel}†_,76 _{T. Arisawa}†_,41 _{A. Artikov}†_,48 J. Asaadi†_,119 _{W. Ashmanskas}†_,76 _{A. Askew}‡_,74 _{S. Atkins}‡_,89_{B. Auerbach}†_,72 _{K. Augsten}‡_,9 _{A. Aurisano}†_,119 C. Avila‡_,7 _{F. Azfar}†_,66 _{F. Badaud}‡_,13 _{W. Badgett}†_,76 _{T. Bae}†_,43 _{L. Bagby}‡_,76 _{B. Baldin}‡_,76 _{D.V. Bandurin}‡_,74

S. Banerjee‡_,31 _{A. Barbaro-Galtieri}†_,68 _{E. Barberis}‡_,92 _{P. Baringer}‡_,87 _{V.E. Barnes}†_,85 _{B.A. Barnett}†_,90 P. Barria†♯d_,36 _{J.F. Bartlett}‡_,76 _{P. Bartos}†_,53 _{U. Bassler}‡_,18 _{M. Bauce}†♯b_,35 _{V. Bazterra}‡_,78 _{A. Bean}‡_,87 F. Bedeschi†_,36 _{M. Begalli}‡_,2_{S. Behari}†_,90 _{L. Bellantoni}‡_,76 _{G. Bellettini}†♯c_,36 _{J. Bellinger}†_,125_{D. Benjamin}†_,109

A. Beretvas†_,76 _{S.B. Beri}‡_,29 _{G. Bernardi}‡_,17_{R. Bernhard}‡_,22 _{I. Bertram}‡_,61 _{M. Besan¸con}‡_,18_{R. Beuselinck}‡_,63 P.C. Bhat‡_,76 _{S. Bhatia}‡_,99 _{V. Bhatnagar}‡_,29 _{A. Bhatti}†_,105 _{D. Bisello}†♯b_,35 _{I. Bizjak}†_,64 _{K.R. Bland}†_,122 G. Blazey‡_,79 _{S. Blessing}‡_,74 _{K. Bloom}‡_,100 _{B. Blumenfeld}†_,90 _{A. Bocci}†_,109 _{A. Bodek}†_,106 _{A. Boehnlein}‡_,76

D. Boline‡_,107 _{E.E. Boos}‡_,50 _{G. Borissov}‡_,61 _{D. Bortoletto}†_,85 _{T. Bose}‡_,91 _{J. Boudreau}†_,116 _{A. Boveia}†_,77 A. Brandt‡_,118 _{O. Brandt}‡_,23 _{L. Brigliadori}†♯a_,33 _{R. Brock}‡_,98 _{C. Bromberg}†_,98 _{A. Bross}‡_,76 _{D. Brown}‡_,17 J. Brown‡_,17 _{E. Brucken}†_,12 _{J. Budagov}†_,48 _{X.B. Bu}‡_,76 _{H.S. Budd}†_,106 _{M. Buehler}‡_,76 _{V. Buescher}‡_,25 V. Bunichev‡_,50 _{S. Burdin}‡b_,61 _{K. Burkett}†_,76 _{G. Busetto}†♯b_,35 _{P. Bussey}†_,60 _{C.P. Buszello}‡_,58 _{A. Buzatu}†_,4 A. Calamba†_,115 _{C. Calancha}†_,56 _{E. Camacho-P´erez}‡_,45 _{S. Camarda}†_,54 _{M. Campanelli}†_,64 _{M. Campbell}†_,96 F. Canelli†_,77 _{B. Carls}†_,81 _{D. Carlsmith}†_,125 _{R. Carosi}†_,36 _{S. Carrillo}†c_,73_{S. Carron}†_,76 _{B. Casal}†d_,57_{M. Casarsa}†_,38 B.C.K. Casey‡_,76_{H. Castilla-Valdez}‡_,45_{A. Castro}†♯a_,33_{P. Catastini}†_,93 _{S. Caughron}‡_,98_{D. Cauz}†_,38_{V. Cavaliere}†_,81

M. Cavalli-Sforza†_,54 _{A. Cerri}†e_,68 _{L. Cerrito}†f_,64 _{S. Chakrabarti}‡_,107 _{D. Chakraborty}‡_,79 _{K.M. Chan}‡_,84 A. Chandra‡_,121 _{E. Chapon}‡_,18 _{G. Chen}‡_,87_{Y.C. Chen}†_,6 _{M. Chertok}†_,69 _{S. Chevalier-Th´ery}‡_,18 _{G. Chiarelli}†_,36

G. Chlachidze†_,76 _{F. Chlebana}†_,76 _{D.K. Cho}‡_,117 _{K. Cho}†_,43 _{S.W. Cho}‡_,44 _{S. Choi}‡_,44 _{D. Chokheli}†_,48 B. Choudhary‡_,30_{W.H. Chung}†_,125 _{Y.S. Chung}†_,106 _{S. Cihangir}‡_,76 _{M.A. Ciocci}†♯d_,36 _{D. Claes}‡_,100 _{A. Clark}†_,59 C. Clarke†_,97 _{J. Clutter}‡_,87 _{G. Compostella}†♯b_,35_{M.E. Convery}†_,76 _{J. Conway}†_,69_{M. Cooke}‡_,76 _{W.E. Cooper}‡_,76 M. Corbo†_,76 _{M. Corcoran}‡_,121 _{M. Cordelli}†_,34 _{F. Couderc}‡_,18 _{M.-C. Cousinou}‡_,15 _{C.A. Cox}†_,69 _{D.J. Cox}†_,69 F. Crescioli†♯c_,36 _{A. Croc}‡_,18_{J. Cuevas}†a_,57 _{R. Culbertson}†_,76 _{D. Cutts}‡_,117 _{D. Dagenhart}†_,76 _{N. d’Ascenzo}†g_,76 A. Das‡_,67_{M. Datta}†_,76_{G. Davies}‡_,63_{P. de Barbaro}†_,106 _{S.J. de Jong}‡_,46, 47 _{E. De La Cruz-Burelo}‡_,45_{F. D´eliot}‡_,18 M. Dell’Orso†♯c_,36_{R. Demina}‡_,106_{L. Demortier}†_,105_{M. Deninno}†_,33 _{D. Denisov}‡_,76_{S.P. Denisov}‡_,51_{M. d’Errico}†♯b_,35

S. Desai‡_,76_{C. Deterre}‡_,18 _{K. DeVaughan}‡_,100 _{F. Devoto}†_,12 _{A. Di Canto}†♯c_,36 _{B. Di Ruzza}†_,76 _{H.T. Diehl}‡_,76 M. Diesburg‡_,76_{P.F. Ding}‡_,65 _{J.R. Dittmann}†_,122_{A. Dominguez}‡_,100 _{S. Donati}†♯c_,36 _{P. Dong}†_,76 _{M. D’Onofrio}†_,62

M. Dorigo†_,38 _{T. Dorigo}†_,35 _{A. Dubey}‡_,30 _{L.V. Dudko}‡_,50 _{D. Duggan}‡_,101 _{A. Duperrin}‡_,15 _{S. Dutt}‡_,29 A. Dyshkant‡_,79 _{M. Eads}‡_,100_{K. Ebina}†_,41_{D. Edmunds}‡_,98 _{A. Elagin}†_,119 _{J. Ellison}‡_,71 _{V.D. Elvira}‡_,76 _{Y. Enari}‡_,17

A. Eppig†_,96 _{R. Erbacher}†_,69 _{S. Errede}†_,81 _{N. Ershaidat}†h_,76_{R. Eusebi}†_,119 _{H. Evans}‡_,82_{A. Evdokimov}‡_,108 V.N. Evdokimov‡_,51_{G. Facini}‡_,92 _{S. Farrington}†_,66 _{M. Feindt}†_,24 _{L. Feng}‡_,79 _{T. Ferbel}‡_,106_{J.P. Fernandez}†_,56

F. Fiedler‡_,25 _{R. Field}†_,73 _{F. Filthaut}‡_,46, 47 _{W. Fisher}‡_,98 _{H.E. Fisk}‡_,76 _{G. Flanagan}†i_,76 _{R. Forrest}†_,69 M. Fortner‡_,79_{H. Fox}‡_,61_{M.J. Frank}†_,122 _{M. Franklin}†_,93 _{J.C. Freeman}†_,76_{S. Fuess}‡_,76_{Y. Funakoshi}†_,41_{I. Furic}†_,73

M. Gallinaro†_,105_{A. Garcia-Bellido}‡_,106 _{J.E. Garcia}†_,59 _{J.A. Garc´ıa-Gonz´alez}‡_,45 _{G.A. Garc´ıa-Guerra}‡c_,45 A.F. Garfinkel†_,85_{P. Garosi}†♯d_,36_{V. Gavrilov}‡_,49 _{P. Gay}‡_,13 _{W. Geng}‡_,15, 98 _{D. Gerbaudo}‡_,102 _{C.E. Gerber}‡_,78

H. Gerberich†_,81 _{E. Gerchtein}†_,76 _{Y. Gershtein}‡_,101 _{S. Giagu}†_,37 _{V. Giakoumopoulou}†_,28 _{P. Giannetti}†_,36 K. Gibson†_,116_{C.M. Ginsburg}†_,76 _{G. Ginther}‡_,76, 106 _{N. Giokaris}†_,28 _{P. Giromini}†_,34_{G. Giurgiu}†_,90 _{V. Glagolev}†_,48

D. Glenzinski†_,76 _{M. Gold}†_,103 _{D. Goldin}†_,119 _{N. Goldschmidt}†_,73 _{A. Golossanov}†_,76 _{G. Golovanov}‡_,48 G. Gomez-Ceballos†_,94 _{G. Gomez}†_,57 _{M. Goncharov}†_,94 _{O. Gonz´alez}†_,56 _{I. Gorelov}†_,103 _{A.T. Goshaw}†_,109 K. Goulianos†_,105 _{A. Goussiou}‡_,124_{P.D. Grannis}‡_,107 _{S. Greder}‡_,19 _{H. Greenlee}‡_,76 _{G. Grenier}‡_,20 _{S. Grinstein}†_,54

Ph. Gris‡_,13 _{J.-F. Grivaz}‡_,16 _{A. Grohsjean}‡d_,18 _{C. Grosso-Pilcher}†_,77 _{R.C. Group}†_,123, 76 _{S. Gr¨unendahl}‡_,76 M.W. Gr¨unewald‡_,32_{T. Guillemin}‡_,16 _{J. Guimaraes da Costa}†_,93 _{G. Gutierrez}‡_,76_{P. Gutierrez}‡_,112 _{S. Hagopian}‡_,74

S.R. Hahn†_,76 _{J. Haley}‡_,92 _{E. Halkiadakis}†_,101 _{A. Hamaguchi}†_,40 _{J.Y. Han}†_,106 _{L. Han}‡_,5 _{F. Happacher}†_,34 K. Hara†_,42 _{K. Harder}‡_,65 _{D. Hare}†_,101 _{M. Hare}†_,95 _{A. Harel}‡_,106 _{R.F. Harr}†_,97 _{K. Hatakeyama}†_,122 J.M. Hauptman‡_,86_{C. Hays}†_,66_{J. Hays}‡_,63 _{T. Head}‡_,65_{T. Hebbeker}‡_,21 _{M. Heck}†_,24 _{D. Hedin}‡_,79 _{H. Hegab}‡_,113

J. Heinrich†_,114 _{A.P. Heinson}‡_,71 _{U. Heintz}‡_,117 _{C. Hensel}‡_,23 _{I. Heredia-De La Cruz}‡_,45 _{M. Herndon}†_,125 K. Herner‡_,96 _{G. Hesketh}‡e_,65 _{S. Hewamanage}†_,122 _{M.D. Hildreth}‡_,84 _{R. Hirosky}‡_,123 _{T. Hoang}‡_,74 _{J.D. Hobbs}‡_,107 A. Hocker†_,76 _{B. Hoeneisen}‡_,11 _{J. Hogan}‡_,121 _{M. Hohlfeld}‡_,25 _{W. Hopkins}†j_,76 _{D. Horn}†_,24_{S. Hou}†_,6 _{I. Howley}‡_,118 Z. Hubacek‡_,9, 18 _{R.E. Hughes}†_,110 _{M. Hurwitz}†_,77 _{U. Husemann}†_,72 _{N. Hussain}†_,4 _{M. Hussein}†_,98_{J. Huston}†_,98 V. Hynek‡_,9_{I. Iashvili}‡_,104_{Y. Ilchenko}‡_,120_{R. Illingworth}‡_,76_{G. Introzzi}†_,36 _{M. Iori}†♯f_,37_{A.S. Ito}‡_,76_{A. Ivanov}†k_,69

S. Jabeen‡_,117 _{M. Jaffr´e}‡_,16 _{E. James}†_,76 _{D. Jang}†_,115 _{A. Jayasinghe}‡_,112_{B. Jayatilaka}†_,109 _{E.J. Jeon}†_,43 M.S. Jeong‡_,44 _{R. Jesik}‡_,63 _{S. Jindariani}†_,76 _{K. Johns}‡_,67 _{E. Johnson}‡_,98 _{M. Johnson}‡_,76 _{A. Jonckheere}‡_,76 M. Jones†_,85 _{P. Jonsson}‡_,63_{K.K. Joo}†_,43 _{J. Joshi}‡_,71 _{S.Y. Jun}†_,115 _{A.W. Jung}‡_,76 _{T.R. Junk}†_,76 _{A. Juste}‡_,55 K. Kaadze‡_,88 _{E. Kajfasz}‡_,15 _{T. Kamon}†_,119_{P.E. Karchin}†_,97 _{D. Karmanov}‡_,50_{A. Kasmi}†_,122 _{P.A. Kasper}‡_,76

Y. Kato†l_,40 _{I. Katsanos}‡_,100 _{R. Kehoe}‡_,120 _{S. Kermiche}‡_,15_{W. Ketchum}†_,77_{J. Keung}†_,114 _{N. Khalatyan}‡_,76 A. Khanov‡_,113 _{A. Kharchilava}‡_,104 _{Y.N. Kharzheev}‡_,48 _{V. Khotilovich}†_,119 _{B. Kilminster}†_,76 _{D.H. Kim}†_,43 H.S. Kim†_,43 _{J.E. Kim}†_,43_{M.J. Kim}†_,34 _{S.B. Kim}†_,43 _{S.H. Kim}†_,42 _{Y.J. Kim}†_,43 _{Y.K. Kim}†_,77 _{N. Kimura}†_,41

M. Kirby†_,76 _{I. Kiselevich}‡_,49 _{S. Klimenko}†_,73 _{K. Knoepfel}†_,76 _{J.M. Kohli}‡_,29 _{K. Kondo}∗†_,41 _{D.J. Kong}†_,43 J. Konigsberg†_,73 _{A.V. Kotwal}†_,109 _{A.V. Kozelov}‡_,51 _{J. Kraus}‡_,99 _{M. Kreps}†_,24 _{J. Kroll}†_,114 _{D. Krop}†_,77 M. Kruse†_,109 _{V. Krutelyov}†m_,119 _{T. Kuhr}†_,24 _{S. Kulikov}‡_,51 _{A. Kumar}‡_,104 _{A. Kupco}‡_,10 _{M. Kurata}†_,42 T. Kurˇca‡_,20 _{V.A. Kuzmin}‡_,50 _{S. Kwang}†_,77 _{A.T. Laasanen}†_,85 _{S. Lami}†_,36 _{S. Lammel}†_,76 _{S. Lammers}‡_,82 M. Lancaster†_,64 _{R.L. Lander}†_,69 _{G. Landsberg}‡_,117 _{K. Lannon}†n_,110 _{A. Lath}†_,101 _{G. Latino}†♯d_,36 _{P. Lebrun}‡_,20

T. LeCompte†_,75 _{E. Lee}†_,119 _{H.S. Lee}‡_,44 _{H.S. Lee}†o_,77 _{J.S. Lee}†_,43 _{S.W. Lee}†p_,119 _{S.W. Lee}‡_,86 _{W.M. Lee}‡_,76 X. Lei‡_,67 _{J. Lellouch}‡_,17 _{S. Leo}†♯c_,36 _{S. Leone}†_,36 _{J.D. Lewis}†_,76 _{H. Li}‡_,14_{L. Li}‡_,71 _{Q.Z. Li}‡_,76 _{J.K. Lim}‡_,44 A. Limosani†q_,109 _{D. Lincoln}‡_,76 _{C.-J. Lin}†_,68 _{M. Lindgren}†_,76 _{J. Linnemann}‡_,98 _{V.V. Lipaev}‡_,51 _{E. Lipeles}†_,114 R. Lipton‡_,76_{A. Lister}†_,59 _{D.O. Litvintsev}†_,76 _{C. Liu}†_,116 _{H. Liu}†_,126 _{H. Liu}‡_,120_{Q. Liu}†_,85 _{T. Liu}†_,76 _{Y. Liu}‡_,5

A. Lobodenko‡_,52 _{S. Lockwitz}†_,72 _{A. Loginov}†_,72 _{M. Lokajicek}‡_,10 _{R. Lopes de Sa}‡_,107 _{H.J. Lubatti}‡_,124 D. Lucchesi†♯b_,35 _{J. Lueck}†_,24 _{P. Lujan}†_,68 _{P. Lukens}†_,76 _{R. Luna-Garcia}‡f_,45_{G. Lungu}†_,105 _{A.L. Lyon}‡_,76

R. Lysak†r_,53 _{J. Lys}†_,68 _{A.K.A. Maciel}‡_,1 _{R. Madar}‡_,18 _{R. Madrak}†_,76 _{K. Maeshima}†_,76 _{P. Maestro}†♯d_,36 R. Maga˜na-Villalba‡_,45 _{S. Malik}†_,105 _{S. Malik}‡_,100 _{V.L. Malyshev}‡_,48 _{G. Manca}†s_,62 _{A. Manousakis-Katsikakis}†_,28

Y. Maravin‡_,88 _{F. Margaroli}†_,37 _{C. Marino}†_,24 _{M. Mart´ınez}†_,54 _{J. Mart´ınez-Ortega}‡_,45 _{P. Mastrandrea}†_,37 K. Matera†_,81 _{M.E. Mattson}†_,97 _{A. Mazzacane}†_,76 _{P. Mazzanti}†_,33 _{R. McCarthy}‡_,107 _{K.S. McFarland}†_,106

C.L. McGivern‡_,65 _{P. McIntyre}†_,119 _{R. McNulty}†t_,62 _{A. Mehta}†_,62 _{P. Mehtala}†_,12 _{M.M. Meijer}‡_,46, 47 A. Melnitchouk‡_,99_{D. Menezes}‡_,79 _{P.G. Mercadante}‡_,3 _{M. Merkin}‡_,50 _{A. Meyer}‡_,21 _{J. Meyer}‡_,23 _{T. Miao}†_,76

F. Miconi‡_,19 _{D. Mietlicki}†_,96 _{A. Mitra}†_,6 _{H. Miyake}†_,42 _{S. Moed}†_,76 _{N. Moggi}†_,33 _{N.K. Mondal}‡_,31 M.N. Mondragon†c_,76 _{C.S. Moon}†_,43 _{R. Moore}†_,76 _{M.J. Morello}†♯e_,36 _{J. Morlock}†_,24_{P. Movilla Fernandez}†_,76 A. Mukherjee†_,76 _{M. Mulhearn}‡_,123 _{Th. Muller}†_,24 _{P. Murat}†_,76_{M. Mussini}†♯a_,33 _{J. Nachtman}†u_,76_{Y. Nagai}†_,42

J. Naganoma†_,41 _{E. Nagy}‡_,15 _{M. Naimuddin}‡_,30 _{I. Nakano}†_,39 _{A. Napier}†_,95 _{M. Narain}‡_,117 _{R. Nayyar}‡_,67 H.A. Neal‡_,96 _{J.P. Negret}‡_,7 _{J. Nett}†_,119 _{M.S. Neubauer}†_,81 _{C. Neu}†_,126 _{P. Neustroev}‡_,52 _{J. Nielsen}†v_,68 L. Nodulman†_,75 _{S.Y. Noh}†_,43 _{O. Norniella}†_,81 _{T. Nunnemann}‡_,26 _{L. Oakes}†_,66 _{S.H. Oh}†_,109 _{Y.D. Oh}†_,43 I. Oksuzian†_,126_{T. Okusawa}†_,40 _{R. Orava}†_,12 _{J. Orduna}‡_,121 _{L. Ortolan}†_,54 _{N. Osman}‡_,15 _{J. Osta}‡_,84 _{M. Padilla}‡_,71

S. Pagan Griso†♯b_,35 _{C. Pagliarone}†_,38 _{A. Pal}‡_,118 _{E. Palencia}†e_,57 _{V. Papadimitriou}†_,76 _{A.A. Paramonov}†_,75 N. Parashar‡_,83 _{V. Parihar}‡_,117 _{S.K. Park}‡_,44 _{R. Partridge}‡g_,117 _{N. Parua}‡_,82 _{J. Patrick}†_,76 _{A. Patwa}‡_,108

G. Pauletta†♯g_,38 _{M. Paulini}†_,115 _{C. Paus}†_,94 _{D.E. Pellett}†_,69 _{B. Penning}‡_,76 _{A. Penzo}†_,38 _{M. Perfilov}‡_,50 Y. Peters‡_,65 _{K. Petridis}‡_,65_{G. Petrillo}‡_,106 _{P. P´etroff}‡_,16 _{T.J. Phillips}†_,109 _{G. Piacentino}†_,36 _{E. Pianori}†_,114

J. Pilot†_,110 _{K. Pitts}†_,81 _{C. Plager}†_,70 _{M.-A. Pleier}‡_,108 _{P.L.M. Podesta-Lerma}‡h_,45 _{V.M. Podstavkov}‡_,76 L. Pondrom†_,125 _{A.V. Popov}‡_,51 _{S. Poprocki}†j_,76 _{K. Potamianos}†_,85 _{A. Pranko}†_,68 _{M. Prewitt}‡_,121 _{D. Price}‡_,82

N. Prokopenko‡_,51 _{F. Prokoshin}†w_,48 _{F. Ptohos}†x_,34 _{G. Punzi}†♯c_,36 _{J. Qian}‡_,96 _{A. Quadt}‡_,23 _{B. Quinn}‡_,99 A. Rahaman†_,116 _{V. Ramakrishnan}†_,125 _{M.S. Rangel}‡_,1 _{K. Ranjan}‡_,30 _{N. Ranjan}†_,85 _{P.N. Ratoff}‡_,61 _{I. Razumov}‡_,51

I. Redondo†_,56 _{P. Renkel}‡_,120 _{P. Renton}†_,66_{M. Rescigno}†_,37 _{T. Riddick}†_,64_{F. Rimondi}†♯a_,33 _{I. Ripp-Baudot}‡_,19 L. Ristori†_,116, 76 _{F. Rizatdinova}‡_,113 _{A. Robson}†_,60 _{T. Rodrigo}†_,57 _{T. Rodriguez}†_,114 _{E. Rogers}†_,81 _{S. Rolli}†y_,95 M. Rominsky‡_,76 _{R. Roser}†_,76 _{A. Ross}‡_,61 _{C. Royon}‡_,18_{P. Rubinov}‡_,76 _{R. Ruchti}‡_,84 _{F. Ruffini}†♯d_,36 _{A. Ruiz}†_,57

J. Russ†_,115 _{V. Rusu}†_,76 _{A. Safonov}†_,119 _{G. Sajot}‡_,14 _{W.K. Sakumoto}†_,106 _{Y. Sakurai}†_,41 _{P. Salcido}‡_,79 A. S´anchez-Hern´andez‡_,45 _{M.P. Sanders}‡_,26 _{L. Santi}†♯g_,38 _{A.S. Santos}‡i_,1 _{K. Sato}†_,42 _{G. Savage}‡_,76 _{V. Saveliev}†g_,76

A. Savoy-Navarro†z_,76 _{L. Sawyer}‡_,89 _{T. Scanlon}‡_,63 _{R.D. Schamberger}‡_,107 _{Y. Scheglov}‡_,52 _{H. Schellman}‡_,80 P. Schlabach†_,76 _{S. Schlobohm}‡_,124 _{A. Schmidt}†_,24 _{E.E. Schmidt}†_,76 _{C. Schwanenberger}‡_,65 _{T. Schwarz}†_,76

R. Schwienhorst‡_,98 _{L. Scodellaro}†_,57 _{A. Scribano}†♯d_,36 _{F. Scuri}†_,36 _{S. Seidel}†_,103_{Y. Seiya}†_,40 _{J. Sekaric}‡_,87 A. Semenov†_,48 _{H. Severini}‡_,112 _{F. Sforza}†♯d_,36 _{E. Shabalina}‡_,23 _{S.Z. Shalhout}†_,69 _{V. Shary}‡_,18 _{S. Shaw}‡_,98 A.A. Shchukin‡_,51 _{T. Shears}†_,62 _{P.F. Shepard}†_,116 _{M. Shimojima}†aa_,42 _{R.K. Shivpuri}‡_,30 _{M. Shochet}†_,77 I. Shreyber-Tecker†_,127_{V. Simak}‡_,9 _{A. Simonenko}†_,48 _{P. Sinervo}†_,4_{P. Skubic}‡_,112 _{P. Slattery}‡_,106 _{K. Sliwa}†_,95

D. Smirnov‡_,84 _{J.R. Smith}†_,69 _{K.J. Smith}‡_,104 _{F.D. Snider}†_,76 _{G.R. Snow}‡_,100 _{J. Snow}‡_,111 _{S. Snyder}‡_,108 A. Soha†_,76 _{S. S¨oldner-Rembold}‡_,65 _{H. Song}†_,116 _{L. Sonnenschein}‡_,21 _{V. Sorin}†_,54 _{K. Soustruznik}‡_,8 P. Squillacioti†♯d_,36 _{R. St. Denis}†_,60 _{M. Stancari}†_,76 _{J. Stark}‡_,14_{O. Stelzer-Chilton}†_,4_{B. Stelzer}†_,4 _{D. Stentz}†b_,76

D.A. Stoyanova‡_,51 _{M. Strauss}‡_,112_{J. Strologas}†_,103_{G.L. Strycker}†_,96 _{Y. Sudo}†_,42 _{A. Sukhanov}†_,76 _{I. Suslov}†_,48 L. Suter‡_,65 _{P. Svoisky}‡_,112 _{M. Takahashi}‡_,65 _{K. Takemasa}†_,42 _{Y. Takeuchi}†_,42 _{J. Tang}†_,77 _{M. Tecchio}†_,96 P.K. Teng†_,6 _{J. Thom}†j_,76 _{J. Thome}†_,115 _{G.A. Thompson}†_,81 _{E. Thomson}†_,114 _{M. Titov}‡_,18 _{D. Toback}†_,119

S. Tokar†_,53 _{V.V. Tokmenin}‡_,48 _{K. Tollefson}†_,98 _{T. Tomura}†_,42 _{D. Tonelli}†_,76 _{S. Torre}†_,34 _{D. Torretta}†_,76 P. Totaro†_,35 _{M. Trovato}†♯e_,36 _{Y.-T. Tsai}‡_,106 _{K. Tschann-Grimm}‡_,107 _{D. Tsybychev}‡_,107 _{B. Tuchming}‡_,18 C. Tully‡_,102 _{F. Ukegawa}†_,42 _{S. Uozumi}†_,43 _{L. Uvarov}‡_,52 _{S. Uvarov}‡_,52 _{S. Uzunyan}‡_,79 _{R. Van Kooten}‡_,82 W.M. van Leeuwen‡_,46_{N. Varelas}‡_,78 _{A. Varganov}†_,96 _{E.W. Varnes}‡_,67 _{I.A. Vasilyev}‡_,51_{F. V´azquez}†c_,73_{G. Velev}†_,76 C. Vellidis†_,76_{P. Verdier}‡_,20_{A.Y. Verkheev}‡_,48_{L.S. Vertogradov}‡_,48 _{M. Verzocchi}‡_,76 _{M. Vesterinen}‡_,65_{M. Vidal}†_,85

I. Vila†_,57 _{D. Vilanova}‡_,18 _{R. Vilar}†_,57 _{J. Viz´an}†_,57 _{M. Vogel}†_,103 _{P. Vokac}‡_,9 _{G. Volpi}†_,34 _{P. Wagner}†_,114 R.L. Wagner†_,76_{H.D. Wahl}‡_,74_{T. Wakisaka}†_,40 _{R. Wallny}†_,70 _{S.M. Wang}†_,6 _{M.H.L.S. Wang}‡_,76_{A. Warburton}†_,4 J. Warchol‡_,84 _{D. Waters}†_,64 _{G. Watts}‡_,124 _{M. Wayne}‡_,84 _{J. Weichert}‡_,25 _{L. Welty-Rieger}‡_,80 _{W.C. Wester III}†_,76

A. White‡_,118 _{D. Whiteson}†bb_,114 _{F. Wick}†_,24 _{D. Wicke}‡_,27_{A.B. Wicklund}†_,75 _{E. Wicklund}†_,76 _{S. Wilbur}†_,77 H.H. Williams†_,114 _{M.R.J. Williams}‡_,61 _{G.W. Wilson}‡_,87 _{J.S. Wilson}†_,110 _{P. Wilson}†_,76 _{B.L. Winer}†_,110 P. Wittich†j_,76 _{M. Wobisch}‡_,89_{S. Wolbers}†_,76 _{H. Wolfe}†_,110_{D.R. Wood}‡_,92 _{T. Wright}†_,96_{X. Wu}†_,59_{Z. Wu}†_,122 T.R. Wyatt‡_,65 _{Y. Xie}‡_,76_{R. Yamada}‡_,76 _{K. Yamamoto}†_,40 _{D. Yamato}†_,40_{S. Yang}‡_,5 _{T. Yang}†_,76_{U.K. Yang}†cc_,77 W.-C. Yang‡_,65 _{Y.C. Yang}†_,43 _{W.-M. Yao}†_,68 _{T. Yasuda}‡_,76_{Y.A. Yatsunenko}‡_,48 _{W. Ye}‡_,107 _{Z. Ye}‡_,76 _{G.P. Yeh}†_,76 K. Yi†u_,76_{H. Yin}‡_,76 _{K. Yip}‡_,108 _{J. Yoh}†_,76 _{K. Yorita}†_,41 _{T. Yoshida}†dd_,40 _{S.W. Youn}‡_,76 _{G.B. Yu}†_,109_{I. Yu}†_,43

J.M. Yu‡_,96 _{S.S. Yu}†_,76 _{J.C. Yun}†_,76 _{A. Zanetti}†_,38 _{Y. Zeng}†_,109 _{J. Zennamo}‡_,104 _{T. Zhao}‡_,124 _{T.G. Zhao}‡_,65 B. Zhou‡_,96 _{C. Zhou}†_,109 _{J. Zhu}‡_,96 _{M. Zielinski}‡_,106 _{D. Zieminska}‡_,82 _{L. Zivkovic}‡_,117_{and S. Zucchelli}†♯a33

(CDF† _{and D0}‡ _{Collaborations)}

1_{LAFEX, Centro Brasileiro de Pesquisas F´ısicas, Rio de Janeiro, Brazil} 2_{Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil}

3_{Universidade Federal do ABC, Santo Andr´e, Brazil} 4_{Institute of Particle Physics: McGill University, Montr´eal, Qu´ebec,} Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia,

Canada V5A 1S6; University of Toronto, Toronto, Ontario,

Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 5_{University of Science and Technology of China, Hefei, People’s Republic of China} 6_{Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China}

7_{Universidad de los Andes, Bogot´a, Colombia} 8_{Charles University, Faculty of Mathematics and Physics,}

Center for Particle Physics, Prague, Czech Republic 9_{Czech Technical University in Prague, Prague, Czech Republic}

10_{Center for Particle Physics, Institute of Physics,}

Academy of Sciences of the Czech Republic, Prague, Czech Republic 11_{Universidad San Francisco de Quito, Quito, Ecuador} 12_{Division of High Energy Physics, Department of Physics,}

University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland 13_{LPC, Universit´e Blaise Pascal, CNRS/IN2P3, Clermont, France}

14_{LPSC, Universit´e Joseph Fourier Grenoble 1, CNRS/IN2P3,} Institut National Polytechnique de Grenoble, Grenoble, France 15_{CPPM, Aix-Marseille Universit´e, CNRS/IN2P3, Marseille, France}

16_{LAL, Universit´e Paris-Sud, CNRS/IN2P3, Orsay, France} 17_{LPNHE, Universit´es Paris VI and VII, CNRS/IN2P3, Paris, France}

18_{CEA, Irfu, SPP, Saclay, France}

19_{IPHC, Universit´e de Strasbourg, CNRS/IN2P3, Strasbourg, France}

20_{IPNL, Universit´e Lyon 1, CNRS/IN2P3, Villeurbanne, France and Universit´e de Lyon, Lyon, France} 21_{III. Physikalisches Institut A, RWTH Aachen University, Aachen, Germany}

22_{Physikalisches Institut, Universit¨at Freiburg, Freiburg, Germany}

24_{Institut f¨ur Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany} 25_{Institut f¨ur Physik, Universit¨at Mainz, Mainz, Germany}

26_{Ludwig-Maximilians-Universit¨at M¨unchen, M¨unchen, Germany} 27_{Fachbereich Physik, Bergische Universit¨at Wuppertal, Wuppertal, Germany}

28_{University of Athens, 157 71 Athens, Greece} 29_{Panjab University, Chandigarh, India}

30_{Delhi University, Delhi, India}

31_{Tata Institute of Fundamental Research, Mumbai, India} 32_{University College Dublin, Dublin, Ireland}

33_{Istituto Nazionale di Fisica Nucleare Bologna,} ♯a_{University of Bologna, I-40127 Bologna, Italy} 34_{Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy}

35_{Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,} ♯b_{University of Padova, I-35131 Padova, Italy} 36_{Istituto Nazionale di Fisica Nucleare Pisa,} ♯c_{University of Pisa,}

♯d_{University of Siena and} ♯e_{Scuola Normale Superiore, I-56127 Pisa, Italy} 37_{Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,}

♯f

Sapienza Universit`a di Roma, I-00185 Roma, Italy 38_{Istituto Nazionale di Fisica Nucleare Trieste/Udine,} I-34100 Trieste, ♯g_{University of Udine, I-33100 Udine, Italy}

39_{Okayama University, Okayama 700-8530, Japan} 40_{Osaka City University, Osaka 588, Japan}

41_{Waseda University, Tokyo 169, Japan} 42_{University of Tsukuba, Tsukuba, Ibaraki 305, Japan} 43_{Center for High Energy Physics: Kyungpook National University,}

Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757,

Korea; Chonbuk National University, Jeonju 561-756, Korea 44_{Korea Detector Laboratory, Korea University, Seoul, Korea}

45_{CINVESTAV, Mexico City, Mexico} 46_{Nikhef, Science Park, Amsterdam, the Netherlands} 47_{Radboud University Nijmegen, Nijmegen, the Netherlands}

48_{Joint Institute for Nuclear Research, Dubna, Russia} 49_{Institute for Theoretical and Experimental Physics, Moscow, Russia}

50_{Moscow State University, Moscow, Russia} 51_{Institute for High Energy Physics, Protvino, Russia} 52_{Petersburg Nuclear Physics Institute, St. Petersburg, Russia}

53_{Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia} 54_{Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain} 55_{Instituci´o Catalana de Recerca i Estudis Avan¸cats (ICREA) and Institut de F´ısica d’Altes Energies (IFAE), Barcelona, Spain}

56_{Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain} 57_{Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain}

58_{Uppsala University, Uppsala, Sweden}

59_{University of Geneva, CH-1211 Geneva 4, Switzerland} 60_{Glasgow University, Glasgow G12 8QQ, United Kingdom} 61_{Lancaster University, Lancaster LA1 4YB, United Kingdom} 62_{University of Liverpool, Liverpool L69 7ZE, United Kingdom} 63_{Imperial College London, London SW7 2AZ, United Kingdom} 64_{University College London, London WC1E 6BT, United Kingdom} 65_{The University of Manchester, Manchester M13 9PL, United Kingdom}

66_{University of Oxford, Oxford OX1 3RH, United Kingdom} 67_{University of Arizona, Tucson, Arizona 85721, USA}

68_{Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA} 69_{University of California, Davis, Davis, California 95616, USA}

70_{University of California, Los Angeles, Los Angeles, California 90024, USA} 71_{University of California Riverside, Riverside, California 92521, USA}

72_{Yale University, New Haven, Connecticut 06520, USA} 73_{University of Florida, Gainesville, Florida 32611, USA} 74_{Florida State University, Tallahassee, Florida 32306, USA} 75_{Argonne National Laboratory, Argonne, Illinois 60439, USA} 76_{Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA} 77_{Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA}

78_{University of Illinois at Chicago, Chicago, Illinois 60607, USA} 79_{Northern Illinois University, DeKalb, Illinois 60115, USA}

80_{Northwestern University, Evanston, Illinois 60208, USA} 81_{University of Illinois, Urbana, Illinois 61801, USA} 82_{Indiana University, Bloomington, Indiana 47405, USA} 83_{Purdue University Calumet, Hammond, Indiana 46323, USA} 84_{University of Notre Dame, Notre Dame, Indiana 46556, USA}

85_{Purdue University, West Lafayette, Indiana 47907, USA} 86_{Iowa State University, Ames, Iowa 50011, USA} 87_{University of Kansas, Lawrence, Kansas 66045, USA} 88_{Kansas State University, Manhattan, Kansas 66506, USA} 89_{Louisiana Tech University, Ruston, Louisiana 71272, USA} 90_{The Johns Hopkins University, Baltimore, Maryland 21218, USA}

91_{Boston University, Boston, Massachusetts 02215, USA} 92_{Northeastern University, Boston, Massachusetts 02115, USA}

93_{Harvard University, Cambridge, Massachusetts 02138, USA}

94_{Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA} 95_{Tufts University, Medford, Massachusetts 02155, USA}

96_{University of Michigan, Ann Arbor, Michigan 48109, USA} 97_{Wayne State University, Detroit, Michigan 48201, USA} 98_{Michigan State University, East Lansing, Michigan 48824, USA}

99_{University of Mississippi, University, Mississippi 38677, USA} 100_{University of Nebraska, Lincoln, Nebraska 68588, USA} 101_{Rutgers University, Piscataway, New Jersey 08855, USA} 102_{Princeton University, Princeton, New Jersey 08544, USA} 103_{University of New Mexico, Albuquerque, New Mexico 87131, USA}

104_{State University of New York, Buffalo, New York 14260, USA} 105_{The Rockefeller University, New York, New York 10065, USA} 106_{University of Rochester, Rochester, New York 14627, USA} 107_{State University of New York, Stony Brook, New York 11794, USA}

108_{Brookhaven National Laboratory, Upton, New York 11973, USA} 109_{Duke University, Durham, North Carolina 27708, USA} 110_{The Ohio State University, Columbus, Ohio 43210, USA}

111_{Langston University, Langston, Oklahoma 73050, USA} 112_{University of Oklahoma, Norman, Oklahoma 73019, USA} 113_{Oklahoma State University, Stillwater, Oklahoma 74078, USA} 114_{University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA}

115_{Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA} 116_{University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA}

117_{Brown University, Providence, Rhode Island 02912, USA} 118_{University of Texas, Arlington, Texas 76019, USA} 119_{Texas A&M University, College Station, Texas 77843, USA}

120_{Southern Methodist University, Dallas, Texas 75275, USA} 121_{Rice University, Houston, Texas 77005, USA} 122_{Baylor University, Waco, Texas 76798, USA} 123_{University of Virginia, Charlottesville, Virginia 22904, USA} 124_{University of Washington, Seattle, Washington 98195, USA} 125_{University of Wisconsin, Madison, Wisconsin 53706, USA} 126_{University of Virginia, Charlottesville, Virginia 22906, USA}

127_{Institution for Theoretical and Experimental Physics, ITEP, Moscow 117259, Russia} (Dated: July 12, 2012)

The combination of searches performed by the CDF and D0 collaborations at the Fermilab Teva-tron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb−1_{of integrated luminosity at CDF and 5.2 fb}−1 _{at D0, have been collected} in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The re-sults are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.

PACS numbers: 14.80.Da, 12.38.Qk, 12.60.Fr, 13.85.Rm

∗_Deceased

In the standard model (SM), electroweak symmetry breaking is achieved through the introduction of a single scalar doublet field and the existence of a single neu-tral scalar boson [1–6] is predicted. However, exten-sions of the SM exist with richer structure. Introduc-ing a second Higgs doublet, such as in Type II 2-Higgs Doublet Models (2HDM) [7], leads to multiple scalar bosons and can give scenarios with enhanced couplings to down-type fermions. Supersymmetry is a plausible extension to the SM that introduces an additional sym-metry between fermions and bosons. The two Higgs bo-son doublets in the minimal supersymmetric standard model (MSSM) [8, 9] lead to five physical Higgs bosons: three neutral (collectively denoted as φ): h, H, and A; and two charged: H+ _{and H}−_{. At leading order the} MSSM is a Type II 2HDM model, and two parameters are sufficient to describe the Higgs sector. These are con-ventionally chosen as the ratio of the two Higgs doublet vacuum expectation values, tan β, and, MA, the mass of the pseudoscalar boson, A. The couplings to the down-type fermions are enhanced by a factor of tan β relative to those in the SM. Thus, the main decay mode is φ → b

¯, with branching fractions near 90% at leading order (the remainder being mostly φ → τ+_τ−_{). While searches}

Oviedo, Spain, †b_{Northwestern University, Evanston, IL 60208,}

USA,†c_{Universidad Iberoamericana, Mexico D.F., Mexico,}†d_ETH,

8092 Zurich, Switzerland, †e_{CERN, CH-1211 Geneva,}

Switzer-land, †f_{Queen Mary, University of London, London, E1 4NS,}

United Kingdom,†g_{National Research Nuclear University, Moscow,}

Russia, †h_{Yarmouk University, Irbid 211-63, Jordan,} †i_Muons,

Inc., Batavia, IL 60510, USA, †j_{Cornell University, Ithaca, NY}

14853, USA, †k_{Kansas State University, Manhattan, KS 66506,}

USA, †l_{Kinki University, Higashi-Osaka City, Japan 577-8502,} †m_{University of CA Santa Barbara, Santa Barbara, CA 93106,}

USA, †n_{University of Notre Dame, Notre Dame, IN 46556,}

USA,†o_{Ewha Womans University, Seoul, 120-750, Korea,}†p_Texas

Tech University, Lubbock, TX 79609, USA,†q_{University of}

Mel-bourne, Victoria 3010, Australia,†r_{Institute of Physics, Academy}

of Sciences of the Czech Republic, Czech Republic, †s_Istituto

Nazionale di Fisica Nucleare, Sezione di Cagliari, 09042 Monserrato (Cagliari), Italy, †t_{University College Dublin, Dublin 4, Ireland,} †u_{University of Iowa, Iowa City, IA 52242, USA,}†v_{University of}

CA Santa Cruz, Santa Cruz, CA 95064, USA,†w_Universidad

Tec-nica Federico Santa Maria, 110v Valparaiso, Chile, †x_University

of Cyprus, Nicosia CY-1678, Cyprus,†y_{Office of Science, U.S.}

De-partment of Energy, Washington, DC 20585, USA,†z_CNRS-IN2P3,

Paris, F-75205 France, †aa_{Nagasaki Institute of Applied Science,}

Nagasaki, Japan, †bb_{University of CA Irvine, Irvine, CA 92697,}

USA,†cc_{University of Manchester, Manchester M13 9PL, United}

Kingdom, and †dd_{University of Fukui, Fukui City, Fukui}

Prefec-ture, Japan 910-0017.

‡_{and D0 visitors from}‡a_{Augustana College, Sioux Falls, SD, USA,} ‡b_{The University of Liverpool, Liverpool, UK,} ‡c_UPIITA-IPN,

Mexico City, Mexico, ‡d_{DESY, Hamburg, Germany,} ‡e_University

College London, London, UK,‡f_{Centro de Investigacion en}

Com-putacion - IPN, Mexico City, Mexico,‡g_{SLAC, Menlo Park, CA,}

USA,‡h_{ECFM, Universidad Autonoma de Sinaloa, Culiac´an,}

Mex-ico and‡i_{Universidade Estadual Paulista, S˜ao Paulo, Brazil.}

for τ -lepton-pair final states at hadron colliders are rel-atively insensitive to higher-order radiative corrections, due to cancellations between the production and decay processes, this is not the case for decays to b

¯. Thus, information from decays to b¯b together with stringent limits from decays to τ+_τ−_{can constrain higher-order} ef-fects and yield additional information about electroweak symmetry breaking, supersymmetry or other new physics beyond the SM with similar final states such as pair pro-duction of color octet scalars [12–14].

Since an inclusive search for φ → b

¯ is difficult due to large multijet backgrounds, these searches rely on the case where the φ boson is produced in association with one or more b quarks. This final state with at least three b quarks represents a powerful search channel, with the third b jet providing additional suppression of the large multijet background at a hadron collider.

MSSM Higgs boson production has been studied at the CERN LEP e+_e− _{collider excluding M}

h,A< 93 GeV for all tan β values [15]. The CDF [16–18] and D0 [19–28] collaborations extended such searches to higher masses and for large tan β. The most stringent upper limits on tan β in searches for neutral Higgs production for masses above the LEP bounds come from searches in final states with τ leptons pair produced at the Large Hadron Col-lider [29–31].

The results reported in this Article make use of p¯p col-lisions at a center of mass energy of 1.96 TeV. The data, corresponding to integrated luminosities of 2.6 fb−1 and 5.2 fb−1 , were collected during Run II at the Fermilab Tevatron Collider by the CDF and D0 collaborations, re-spectively. The combination of searches for neutral Higgs bosons in final states with three or more b jets [18, 25] is presented.

The CDF and D0 detectors are described in Ref. [32– 35]. A brief outline of the reconstruction of the final states and event selection used in these searches fol-lows. A cone algorithm [36] with a radius of R = p(∆y)2_{+ (∆ϕ)}2 _{= 0.7 (CDF) and 0.5 (D0), where y} is the rapidity and ϕ the azimuthal angle, is used to re-construct jets from energy deposition in the calorimeters. Identification of jets arising from b-quark fragmentation (b-tagging) uses an algorithm based on reconstructing secondary vertices of charged particles displaced from the p¯p interaction vertex at CDF [37] and a neural network combining lifetime information from secondary vertices and the minimum distance of approach of charged parti-cle trajectories to the primary interaction at D0 [38].

Events are selected at CDF with dedicated online event selections (triggers) requiring at least two jets and us-ing b-taggus-ing information, while at least three jets are required at D0. For most of the data collected at D0, b-tagging information is also used in the trigger decision. Events are selected offline with at least three jets within the fiducial region. This is defined by requirements on the momentum transverse to the proton beam direction,

pT, and detector pseudorapidity, ηdet = − ln(tan(θ/2)), of jets, where θ is the polar angle with respect to the proton beam direction and an origin at the center of the detector: three jets with pT > 20 GeV and |ηdet| < 2.0 at CDF and three jets with pT > 20 GeV and at least two jets with pT > 25 GeV, |ηdet| < 2.5 at D0. Events with more jets are accepted at CDF but only the leading (in pT) four jets are used in the analysis. Exclusive channels with exactly three or exactly four jets are used at D0. The signal sample is defined by both experiments requir-ing at least three b-tagged jets. In the CDF inclusive and the D0 4-jet channel the two leading jets and at least one of the third and fourth jets are required to be b tagged. In addition, a large sample requiring only two b-tagged jets is used by both experiments to build models of the multijet backgrounds.

At CDF, the background is modeled using a sum of templates of the invariant mass distribution of the lead-ing two jets, representlead-ing contributions from different background modes categorized according to kinematics and flavor content. The templates are constructed from events in the double-tagged data sample where at least one of the leading two jets is b-tagged. The events are then weighted according to the probability for at least one of the jets with no b tag to pass the tagging requirements under three different assumptions as to whether it arises from a b quark, a c quark or a light quark (or gluon). This results in six different mass templates. The separa-tion between the different components is enhanced by us-ing an additional jet-flavor-sensitive discriminant, xtags, that makes use of kinematic properties of the charged particles from secondary vertices associated with each b-tagged jet.

In the D0 analysis the background model is formed by correcting the shape of the dijet invariant mass distribu-tion of a data sample with two b-tagged jets using the ratio of simulated multijet samples with three b tags and two b tags. The simulated samples are generated using alpgen [39] with showering and hadronization carried out using pythia [40] and detailed simulation of the de-tector using geant [41]. Their flavor composition, in terms of the relative numbers of b, c and light jets per event, is determined from a simultaneous fit to the data across samples with differing numbers of tagged jets, dif-ferent b-tagger operating points, and in small intervals of the scalar sum of the transverse momenta of the jets. The shape correction is applied as a function of the dijet invariant mass and the value of a likelihood-ratio discrim-inant, L, designed to select signal-like events in prefer-ence to background-like events. Only the two possible jet pairings from the leading jet plus either the second or third leading jet are considered when forming Higgs candidates, and the choice that gives the highest value of L > 0.65 is selected. If neither pairing in the event is above this threshold then the event is discarded. Sys-tematic uncertainties are assessed to take into account

the imperfect modeling of the background simulation. However, the definition of the correction as a ratio of distributions significantly reduces the sensitivity of the final model to these imperfections. Small contributions to the background from top-quark-pair production are simulated using alpgen and pythia. Backgrounds from other sources, such as Z → b¯b and single-top-quark pro-duction are negligible.

The efficiency for selecting signal is estimated for both analyses using events generated with pythia. Associated production of a φ boson and a b quark, gb → φb, with subsequent decay φ → b¯b, is used to model the signal. The signal cross section, experimental acceptance and the kinematics are corrected to next-to-leading order (NLO) using mcfm [42, 43], weighting events as a function of the kinematics of the leading b-quark jet not associated with the Higgs decay.

Approximately 11 500 events are selected by CDF with at least three b tags and an estimated product of signal efficiency and acceptance varying as a func-tion of Mφ between 0.18% at Mφ = 90 GeV and 0.8% at Mφ = 200 GeV. Approximately 15 000 and 11 000 events with at least three b-tagged jets are accepted in the D0 three-jet and four-jet channels, respectively. The corresponding signal efficiencies for a Higgs of mass Mφ= 200 GeV are 1.2% and 0.6%.

The channels are combined and exclusion limits set, using the modified frequentist technique [44, 45], with a log likelihood ratio (LLR) as test statistic:

LLR = −2 lnp(X|H1) p(X|H0)

, (1)

where p represents the probabilities that the data, X, are drawn from the background-only (H0), and signal-plus-background (H1) hypotheses, respectively. The like-lihoods are constructed from the binned two-dimensional distribution of the dijet invariant mass versus the xtags discriminant for CDF and the binned one-dimensional dijet invariant mass distribution for D0. Theoretical pre-dictions of the absolute rates for the multijet backgrounds have large uncertainties. Therefore, additional scale fac-tors are applied to the background yield in the D0 anal-ysis and the individual templates in the CDF analanal-ysis and introduced into the likelihood as parameters with no external constraints. Systematic uncertainties are intro-duced as either shape or normalization variations to the model probability density functions. These systematics are governed by nuisance parameters together with Gaus-sian constraint terms where appropriate [46]. Sources of uncertainty related to a common component of the luminosity determination and the theoretical modeling of the signal production are considered fully correlated. All other sources of uncertainty are assumed to be un-correlated. The modeling of the b-jet-tagging efficiency and the contamination from light-quark and gluon jets

fake are the dominant sources of uncertainty on the back-ground model. These are implemented as uncertainties that affect the shape of the distributions entering the like-lihood. Additional sub-dominant uncertainties are con-sidered in the D0 analysis arising in the modeling of the trigger, jet efficiency, jet energy scale and jet resolution. While most of those effects have a negligible impact on the background model, effects that are dependent on the differences between b, light, and gluon jets can be signif-icant. Dominant experimental systematic uncertainties on the signal model can be attributed to luminosity (6%), b-tagging efficiency (11-18%) and jet energy scale (2-10% depending on the φ boson mass hypothesis).

Limits on the product of the cross section and the branching ratio using the LLR test statistic are extracted. The limits are model-independent, apart from assuming a single narrow Higgs boson mass peak, dominated by ex-perimental resolution effects. These are summarized in Table I, and presented in Fig. 1. The combination gives a sensitivity that is better than the D0 expected limit alone by ≈ 25% at Mφ = 100 GeV, steadily falling to < 1% by Mφ = 300 GeV. Excesses of events above the SM background expectation are observed for Mφ= 120 and 140 GeV with significances of 2.5 standard deviations and 2.6 standard deviations, respectively. These are driven by the excesses observed in the individual contributing analyses of 2.8 standard deviations at Mφ= 150 GeV at CDF and 2.5 standard deviations at Mφ = 120 GeV at D0. A standard convention [47] is used to account for the effect that it is more likely to find a deviation (under the background-only) hypothesis when several mass regions are probed compared with only a single hypothesis. The significance of the excesses in the combined analysis is reduced to ≈ 2 standard deviations.

Though these limits are the key results of this search, it is interesting to interpret them in terms of constraints on benchmark models within the MSSM. As a conse-quence of the enhanced couplings to b quarks at large tan β, the total width of the Higgs boson increases with tan β. When this width becomes comparable to the ex-perimental resolution of 15-20% there is an impact on the sensitivity of the search. When interpreting the ex-clusion within the MSSM, the width of the Higgs boson and the enhancement of the product of cross section and branching ratio above that of the SM are calculated us-ing feynhiggs [48–53]. The width is included in the simulation of the signal as a function of mass and tan β by convoluting a relativistic Breit-Wigner function with the NLO cross section [42]. Additional uncertainties for these model-specific limits are considered that otherwise cancel in the model-independent limit. For comparison these are derived as in previous results [18, 22, 25]: uncer-tainties on the SM signal cross section are derived from varying the factorization and renormalization scales by a factor of two and from uncertainties on the parton distri-bution functions. The uncertainties assessed from scale

Mφ Obs. Expected (pb) (GeV) (pb) -2 s.d. -1 s.d. median +1 s.d. +2 s.d. 90 38 30 41 57 81 110 100 43 22 30 42 62 86 110 43 15 20 27 39 53 120 44 12 15 20 29 39 130 25 8.1 9.6 14 19 25 140 26 5.1 7.3 10 14 20 150 18 4.1 5.5 7.4 11 15 160 12 3.3 4.5 6.0 8.5 12 170 9.4 2.5 3.6 5.0 7.0 9.5 180 7.1 2.4 3.2 4.2 6.0 8.2 190 5.7 2.2 2.5 4.0 5.0 7.0 200 5.0 2.0 2.4 3.0 4.4 6.0 210 3.8 1.6 2.2 2.6 3.7 5.0 220 3.3 1.2 1.7 2.2 3.2 4.7 230 2.5 1.0 1.5 2.0 3.0 4.1 240 2.0 0.9 1.2 1.8 2.5 3.5 250 2.0 0.9 1.1 1.6 2.3 3.2 260 1.7 0.7 1.0 1.4 2.2 2.8 270 1.3 0.7 0.9 1.2 2.0 2.4 280 1.1 0.6 0.8 1.1 1.7 2.4 290 0.82 0.6 0.8 1.1 1.9 2.4 300 0.71 0.5 0.7 1.0 1.6 2.3

TABLE I: Observed and expected upper limits at the 95% C.L. on the product of cross section and branching ratio σ(gb → φb) × BR(φ → bb), within the acceptance for the highest pT bquark not arising from the Higgs decay [43]. Ex-pected limits are given for the median and for ±1 and ±2 standard deviation (s.d.) variations of the background expec-tation. [GeV] φ M 100 150 200 250 300 b b ) 9 5 % C L [ p b ] →φ BR( × b) φ → (gb σ 1 10 2 10 Observed Expected 1 s.d. ± Expected 2 s.d. ± Expected -1 Tevatron, 2.6-5.2 fb

FIG. 1: Model independent 95% C.L. upper limits on the product of cross section and branching ratio for the combined analyses, assuming a mass degeneracy between two of the three neutral bosons and a Higgs boson width significantly smaller than the experimental resolution. The dark and light shaded regions (color online) correspond to the one and two standard deviation bands around the median expected limit.

variation are taken to be 10% and the parton distribution functions contribute an additional 3.5-13%, depending on the mass hypothesis.

The masses and couplings of the Higgs bosons in the MSSM depend, in addition to tan β and MA, on other pa-rameters through radiative corrections. Limits on tan β as a function of MAare derived for the mmaxh scenario [54] that favors the b¯b final state, assuming a CP-conserving Higgs sector [55] and a negative value of the Higgs sector bilinear coupling µ. Figure 2 shows exclusion limits in the (tan β, MA) plane for this scenario. Adding a further po-tential theoretical uncertainty on the signal cross section of 20%, independent of Mφ, would lead to an increase of 5% in the tan β limit.

[GeV]

M

100

150

200

250

300

β

tan

10

20

30

40

50

60

70

80

90

Observed Expected 1 s.d. ± Exp. 2 s.d. ± Exp. =-200 GeV µ max, h m Tevatron 2.6-5.2 fb-1

FIG. 2: 95% C.L. lower limit in the (MA, tanβ) plane for the mmaxh , µ = −200 GeV, including Higgs boson width effects. The exclusion limit obtained from the LEP experiments is also shown.

In summary, the combination of results on neutral Higgs boson searches in multi-b-jet events from CDF and D0 has been presented. Upper limits are set on the prod-uct of the cross section and branching ratio and con-straints are placed in the (tan β, MA) plane for a partic-ular MSSM scenario. This combination, with more than half the integrated luminosity from the Tevatron still to be analyzed, provides the most stringent limits on neu-tral Higgs boson production and decay in the multi-b-jet mode.

We thank the Fermilab staff and technical staffs of the participating institutions for their vital contribu-tions and acknowledge support from the DOE and NSF (USA), ARC (Australia), CNPq, FAPERJ, FAPESP and FUNDUNESP (Brazil), NSERC (Canada), NSC, CAS and CNSF (China), Colciencias (Colombia), MSMT and GACR (Czech Republic), the Academy of Finland, CEA and CNRS/IN2P3 (France), BMBF and DFG (Ger-many), DAE and DST (India), SFI (Ireland), INFN

(Italy), MEXT (Japan), the Korean World Class Univer-sity Program and NRF (Korea), CONACyT (Mexico), FOM (Netherlands), MON, NRC KI and RFBR (Rus-sia), the Slovak R&D Agency, the Ministerio de Cien-cia e Innovaci´on, and Programa Consolider-Ingenio 2010 (Spain), The Swedish Research Council (Sweden), SNSF (Switzerland), STFC and the Royal Society (United Kingdom), and the A.P Sloan Foundation (USA).

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