Search for Higgs boson production in dilepton and missing energy final states with 5.4 fb(-1) of pp collisions at square root(s) = 1.96 TeV.
V M Abazov, B Abbott, M Abolins, B S Acharya, M Adams, T Adams, E Aguilo, G D Alexeev, G Alkhazov, A Alton, G Alverson, G A Alves, L S Ancu, M Aoki, Y Arnoud, M Arov, A Askew, B Asman, O Atramentov, C Avila, J BackusMayes, F Badaud, L Bagby, B Baldin, D V Bandurin, S Banerjee, E Barberis, A-F Barfuss, P Baringer, J Barreto, J F Bartlett, U Bassler, D Bauer, S Beale, A Bean, M Begalli, M Begel, C Belanger-Champagne, L Bellantoni, J A Benitez, S B Beri, G Bernardi, R Bernhard, I Bertram, M Besançon, R Beuselinck, V A Bezzubov, P C Bhat, V Bhatnagar, G Blazey, S Blessing, K Bloom, A Boehnlein, D Boline, T A Bolton, E E Boos, G Borissov, T Bose, A Brandt, R Brock, G Brooijmans, A Bross, D Brown, X B Bu, D Buchholz, M Buehler, V Buescher, V Bunichev, S Burdin, T H Burnett, C P Buszello, P Calfayan, B Calpas, S Calvet, E Camacho-Pérez, J Cammin, M A Carrasco-Lizarraga, E Carrera, B C K Casey, H Castilla-Valdez, S Chakrabarti, D Chakraborty, K M Chan, A Chandra, E Cheu, S Chevalier-Théry, D K Cho, S W Cho, S Choi, B Choudhary, T Christoudias, S Cihangir, D Claes, J Clutter, M Cooke, W E Cooper, M Corcoran, F Couderc, M-C Cousinou, D Cutts, M Cwiok, A Das, G Davies, K De, S J de Jong, E De la Cruz-Burelo, K DeVaughan, F Déliot, M Demarteau, R Demina, D Denisov, S P Denisov, S Desai, H T Diehl, M Diesburg, A Dominguez, T Dorland, A Dubey, L V Dudko, L Duflot, D Duggan, A Duperrin, S Dutt, A Dyshkant, M Eads, D Edmunds, J Ellison, V D Elvira, Y Enari, S Eno, H Evans, A Evdokimov, V N Evdokimov, G Facini, A V Ferapontov, T Ferbel, F Fiedler, F Filthaut, W Fisher, H E Fisk, M Fortner, H Fox, S Fuess, T Gadfort, C F Galea, A Garcia-Bellido, V Gavrilov, P Gay, W Geist, W Geng, D Gerbaudo, C E Gerber, Y Gershtein, D Gillberg, G Ginther, G Golovanov, B Gómez, A Goussiou, P D Grannis, S Greder, H Greenlee, Z D Greenwood, E M Gregores, G Grenier, Ph Gris, J-F Grivaz, A Grohsjean, S Grünendahl, M W Grünewald, F Guo, J Guo, G Gutierrez, P Gutierrez, A Haas, P Haefner, S Hagopian, J Haley, I Hall, L Han, K Harder, A Harel, J M Hauptman, J Hays, T Hebbeker, D Hedin, J G Hegeman, A P Heinson, U Heintz, C Hensel, I Heredia-De la Cruz, K Herner, G Hesketh, M D Hildreth, R Hirosky, T Hoang, J D Hobbs, B Hoeneisen, M Hohlfeld, S Hossain, P Houben, Y Hu, Z Hubacek, N Huske, V Hynek, I Iashvili, R Illingworth, A S Ito, S Jabeen, M Jaffré, S Jain, D Jamin, R Jesik, K Johns, C Johnson, M Johnson, D Johnston, A Jonckheere, P Jonsson, A Juste, E Kajfasz, D Karmanov, P A Kasper, I Katsanos, V Kaushik, R Kehoe, S Kermiche, N Khalatyan, A Khanov, A Kharchilava, Y N Kharzheev, D Khatidze, M H Kirby, M Kirsch, J M Kohli, A V Kozelov, J Kraus, A Kumar, A Kupco, T Kurca, V A Kuzmin, J Kvita, D Lam, S Lammers, G Landsberg, P Lebrun, H S Lee, W M Lee, A Leflat, J Lellouch, L Li, Q Z Li, S M Lietti, J K Lim, D Lincoln, J Linnemann, V V Lipaev, R Lipton, Y Liu, Z Liu, A Lobodenko, M Lokajicek, P Love, H J Lubatti, R Luna-Garcia, A L Lyon, A K A Maciel, D Mackin, P Mättig, R Magaña-Villalba, P K Mal, S Malik, V L Malyshev, Y Maravin, J Martínez-Ortega, R McCarthy, C L McGivern, M M Meijer, A Melnitchouk, L Mendoza, D Menezes, P G Mercadante, M Merkin, A Meyer, J Meyer, N K Mondal, T Moulik, G S Muanza, M Mulhearn, O Mundal, L Mundim, E Nagy, M Naimuddin, M Narain, R Nayyar, H A Neal, J P Negret, P Neustroev, H Nilsen, H Nogima, S F Novaes, T Nunnemann, G Obrant, D Onoprienko, J Orduna, N Osman, J Osta, R Otec, G J Otero y Garzón, M Owen, M Padilla, P Padley, M Pangilinan, N Parashar, V Parihar, S-J Park, S K Park, J Parsons, R Partridge, N Parua, A Patwa, B Penning, M Perfilov, K Peters, Y Peters, P Pétroff, R Piegaia, J Piper, M-A Pleier, P L M Podesta-Lerma, V M Podstavkov, M-E Pol, P Polozov, A V Popov, M Prewitt, D Price, S Protopopescu, J Qian, A Quadt, B Quinn, M S Rangel, K Ranjan, P N Ratoff, I Razumov, P Renkel, P Rich, M Rijssenbeek, I Ripp-Baudot, F Rizatdinova, S Robinson, M Rominsky, C Royon, P Rubinov, R Ruchti, G Safronov, G Sajot, A Sánchez-Hernández, M P Sanders, B Sanghi, G Savage, L Sawyer, T Scanlon, D Schaile, R D Schamberger, Y Scheglov, H Schellman, T Schliephake, S Schlobohm, C Schwanenberger, R Schwienhorst, J Sekaric, H Severini, E Shabalina, V Shary, A A Shchukin, R K Shivpuri, V Simak, V Sirotenko, P Skubic, P Slattery, D Smirnov, G R Snow, J Snow, S Snyder, S Söldner-Rembold, L Sonnenschein, A Sopczak, M Sosebee, K Soustruznik, B Spurlock, J Stark, V Stolin, D A Stoyanova, J Strandberg, M A Strang, E Strauss, M Strauss, R Ströhmer, D Strom, L Stutte, P Svoisky, M Takahashi, A Tanasijczuk, W Taylor, B Tiller, M Titov, V V Tokmenin, D Tsybychev, B Tuchming, C Tully, P M Tuts, R Unalan, L Uvarov, S Uvarov, S Uzunyan, P J van den Berg, R Van Kooten, W M van Leeuwen, N Varelas, E W Varnes, I A Vasilyev, P Verdier, L S Vertogradov, M Verzocchi, M Vesterinen, D Vilanova, P Vint, P Vokac, H D Wahl, M H L S Wang, J Warchol, G Watts, M Wayne, G Weber, M Weber, M Wetstein, A White, D Wicke, M R J Williams, G W Wilson, S J Wimpenny, M Wobisch, D R Wood, T R Wyatt, Y Xie, C Xu, S Yacoob, R Yamada, W-C Yang, T Yasuda, Y A Yatsunenko, Z Ye, H Yin, K Yip, H D Yoo, S W Youn, J Yu, C Zeitnitz, S Zelitch, T Zhao, B Zhou, J Zhu, M Zielinski, D Zieminska, L Zivkovic, V Zutshi, E G Zverev
ABSTRACT A search for the standard model Higgs boson is presented using events with two charged leptons and large missing transverse energy selected from 5.4 fb(-1) of integrated luminosity in pp collisions at square root(s) = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron collider. No significant excess of events above background predictions is found, and observed (expected) upper limits at 95% confidence level on the rate of Higgs boson production are derived that are a factor of 1.55 (1.36) above the predicted standard model cross section at m(H) = 165 GeV.
-
Citations (0)
-
Cited In (0)
Page 1
Search for Higgs Boson Production in Dilepton and Missing Energy Final States
with 5:4 fb?1of p ? p Collisions at
ffiffiffis
p
¼ 1:96 TeV
V.M. Abazov,37B. Abbott,75M. Abolins,64B.S. Acharya,30M. Adams,50T. Adams,48E. Aguilo,6G.D. Alexeev,37
G. Alkhazov,41A. Alton,64,*G. Alverson,62G.A. Alves,2L.S. Ancu,36M. Aoki,49Y. Arnoud,14M. Arov,59A. Askew,48
B. A˚sman,42O. Atramentov,67C. Avila,8J. BackusMayes,82F. Badaud,13L. Bagby,49B. Baldin,49D.V. Bandurin,58
S. Banerjee,30E. Barberis,62A.-F. Barfuss,15P. Baringer,57J. Barreto,2J.F. Bartlett,49U. Bassler,18D. Bauer,44S. Beale,6
A. Bean,57M. Begalli,3M. Begel,73C. Belanger-Champagne,42L. Bellantoni,49J.A. Benitez,64S.B. Beri,28
G. Bernardi,17R. Bernhard,23I. Bertram,43M. Besanc ¸on,18R. Beuselinck,44V.A. Bezzubov,40P.C. Bhat,49
V. Bhatnagar,28G. Blazey,51S. Blessing,48K. Bloom,66A. Boehnlein,49D. Boline,61T.A. Bolton,58E.E. Boos,39
G. Borissov,43T. Bose,61A. Brandt,78R. Brock,64G. Brooijmans,70A. Bross,49D. Brown,19X.B. Bu,7D. Buchholz,52
M. Buehler,81V. Buescher,25V. Bunichev,39S. Burdin,43,†T.H. Burnett,82C.P. Buszello,44P. Calfayan,26B. Calpas,15
S. Calvet,16E. Camacho-Pe ´rez,34J. Cammin,71M.A. Carrasco-Lizarraga,34E. Carrera,48B.C.K. Casey,49
H. Castilla-Valdez,34S. Chakrabarti,72D. Chakraborty,51K.M. Chan,55A. Chandra,53E. Cheu,46S. Chevalier-The ´ry,18
D.K. Cho,61S.W. Cho,32S. Choi,33B. Choudhary,29T. Christoudias,44S. Cihangir,49D. Claes,66J. Clutter,57M. Cooke,49
W.E. Cooper,49M. Corcoran,80F. Couderc,18M.-C. Cousinou,15D. Cutts,77M. C´wiok,31A. Das,46G. Davies,44K. De,78
S.J. de Jong,36E. De La Cruz-Burelo,34K. DeVaughan,66F. De ´liot,18M. Demarteau,49R. Demina,71D. Denisov,49
S.P. Denisov,40S. Desai,49H.T. Diehl,49M. Diesburg,49A. Dominguez,66T. Dorland,82A. Dubey,29L.V. Dudko,39
L. Duflot,16D. Duggan,67A. Duperrin,15S. Dutt,28A. Dyshkant,51M. Eads,66D. Edmunds,64J. Ellison,47V.D. Elvira,49
Y. Enari,17S. Eno,60H. Evans,53A. Evdokimov,73V.N. Evdokimov,40G. Facini,62A.V. Ferapontov,77T. Ferbel,61,71
F. Fiedler,25F. Filthaut,36W. Fisher,64H.E. Fisk,49M. Fortner,51H. Fox,43S. Fuess,49T. Gadfort,73C.F. Galea,36
A. Garcia-Bellido,71V. Gavrilov,38P. Gay,13W. Geist,19W. Geng,15,64D. Gerbaudo,68C.E. Gerber,50Y. Gershtein,67
D. Gillberg,6G. Ginther,49,71G. Golovanov,37B. Go ´mez,8A. Goussiou,82P.D. Grannis,72S. Greder,19H. Greenlee,49
Z.D. Greenwood,59E.M. Gregores,4G. Grenier,20Ph. Gris,13J.-F. Grivaz,16A. Grohsjean,18S. Gru ¨nendahl,49
M.W. Gru ¨newald,31F. Guo,72J. Guo,72G. Gutierrez,49P. Gutierrez,75A. Haas,70,‡P. Haefner,26S. Hagopian,48J. Haley,62
I. Hall,64L. Han,7K. Harder,45A. Harel,71J.M. Hauptman,56J. Hays,44T. Hebbeker,21D. Hedin,51J.G. Hegeman,35
A.P. Heinson,47U. Heintz,77C. Hensel,24I. Heredia-De La Cruz,34K. Herner,63G. Hesketh,62M.D. Hildreth,55
R. Hirosky,81T. Hoang,48J.D. Hobbs,72B. Hoeneisen,12M. Hohlfeld,25S. Hossain,75P. Houben,35Y. Hu,72Z. Hubacek,10
N. Huske,17V. Hynek,10I. Iashvili,69R. Illingworth,49A.S. Ito,49S. Jabeen,61M. Jaffre ´,16S. Jain,69D. Jamin,15R. Jesik,44
K. Johns,46C. Johnson,70M. Johnson,49D. Johnston,66A. Jonckheere,49P. Jonsson,44A. Juste,49,xE. Kajfasz,15
D. Karmanov,39P.A. Kasper,49I. Katsanos,66V. Kaushik,78R. Kehoe,79S. Kermiche,15N. Khalatyan,49A. Khanov,76
A. Kharchilava,69Y.N. Kharzheev,37D. Khatidze,77M.H. Kirby,52M. Kirsch,21J.M. Kohli,28A.V. Kozelov,40J. Kraus,64
A. Kumar,69A. Kupco,11T. Kurc ˇa,20V.A. Kuzmin,39J. Kvita,9D. Lam,55S. Lammers,53G. Landsberg,77P. Lebrun,20
H.S. Lee,32W.M. Lee,49A. Leflat,39J. Lellouch,17L. Li,47Q.Z. Li,49S.M. Lietti,5J.K. Lim,32D. Lincoln,49
J. Linnemann,64V.V. Lipaev,40R. Lipton,49Y. Liu,7Z. Liu,6A. Lobodenko,41M. Lokajicek,11P. Love,43H.J. Lubatti,82
R. Luna-Garcia,34,kA.L. Lyon,49A.K.A. Maciel,2D. Mackin,80P. Ma ¨ttig,27R. Magan ˜a-Villalba,34P.K. Mal,46
S. Malik,66V.L. Malyshev,37Y. Maravin,58J. Martı ´nez-Ortega,34R. McCarthy,72C.L. McGivern,57M.M. Meijer,36
A. Melnitchouk,65L. Mendoza,8D. Menezes,51P.G. Mercadante,4M. Merkin,39A. Meyer,21J. Meyer,24N.K. Mondal,30
T. Moulik,57G.S. Muanza,15M. Mulhearn,81O. Mundal,22L. Mundim,3E. Nagy,15M. Naimuddin,29M. Narain,77
R. Nayyar,29H.A. Neal,63J.P. Negret,8P. Neustroev,41H. Nilsen,23H. Nogima,3S.F. Novaes,5T. Nunnemann,26
G. Obrant,41D. Onoprienko,58J. Orduna,34N. Osman,44J. Osta,55R. Otec,10G.J. Otero y Garzo ´n,1M. Owen,45
M. Padilla,47P. Padley,80M. Pangilinan,77N. Parashar,54V. Parihar,77S.-J. Park,24S.K. Park,32J. Parsons,70
R. Partridge,77N. Parua,53A. Patwa,73B. Penning,49M. Perfilov,39K. Peters,45Y. Peters,45P. Pe ´troff,16R. Piegaia,1
J. Piper,64M.-A. Pleier,73P.L.M. Podesta-Lerma,34,{V.M. Podstavkov,49M.-E. Pol,2P. Polozov,38A.V. Popov,40
M. Prewitt,80D. Price,53S. Protopopescu,73J. Qian,63A. Quadt,24B. Quinn,65M.S. Rangel,16K. Ranjan,29P.N. Ratoff,43
I. Razumov,40P. Renkel,79P.Rich,45M. Rijssenbeek,72I. Ripp-Baudot,19F.Rizatdinova,76S. Robinson,44M.Rominsky,75
C. Royon,18P. Rubinov,49R. Ruchti,55G. Safronov,38G. Sajot,14A. Sa ´nchez-Herna ´ndez,34M.P. Sanders,26B. Sanghi,49
G. Savage,49L. Sawyer,59T. Scanlon,44D. Schaile,26R.D. Schamberger,72Y. Scheglov,41H. Schellman,52
T. Schliephake,27S. Schlobohm,82C. Schwanenberger,45R. Schwienhorst,64J. Sekaric,57H. Severini,75E. Shabalina,24
V. Shary,18A.A. Shchukin,40R.K. Shivpuri,29V. Simak,10V. Sirotenko,49P. Skubic,75P. Slattery,71D. Smirnov,55
PRL 104, 061804 (2010)
Selected for a Viewpoint in Physics
PHYSICAL REVIEW LETTERS
week ending
12 FEBRUARY 2010
0031-9007=10=104(6)=061804(7)061804-1
? 2010 The American Physical Society
Page 2
G.R. Snow,66J. Snow,74S. Snyder,73S. So ¨ldner-Rembold,45L. Sonnenschein,21A. Sopczak,43M. Sosebee,78
K. Soustruznik,9B. Spurlock,78J. Stark,14V. Stolin,38D.A. Stoyanova,40J. Strandberg,63M.A. Strang,69E. Strauss,72
M. Strauss,75R. Stro ¨hmer,26D. Strom,50L. Stutte,49P. Svoisky,36M. Takahashi,45A. Tanasijczuk,1W. Taylor,6B. Tiller,26
M. Titov,18V.V. Tokmenin,37D. Tsybychev,72B. Tuchming,18C. Tully,68P.M. Tuts,70R. Unalan,64L. Uvarov,41
S. Uvarov,41S. Uzunyan,51P.J. van den Berg,35R. Van Kooten,53W.M. van Leeuwen,35N. Varelas,50E.W. Varnes,46
I.A. Vasilyev,40P. Verdier,20L.S. Vertogradov,37M. Verzocchi,49M. Vesterinen,45D. Vilanova,18P. Vint,44P. Vokac,10
H.D. Wahl,48M.H.L.S. Wang,71J. Warchol,55G. Watts,82M. Wayne,55G. Weber,25M. Weber,49,**M. Wetstein,60
A. White,78D. Wicke,25M.R.J. Williams,43G.W. Wilson,57S.J. Wimpenny,47M. Wobisch,59D.R. Wood,62
T.R. Wyatt,45Y. Xie,49C. Xu,63S. Yacoob,52R. Yamada,49W.-C. Yang,45T. Yasuda,49Y.A. Yatsunenko,37Z. Ye,49
H. Yin,7K. Yip,73H.D. Yoo,77S.W. Youn,49J. Yu,78C. Zeitnitz,27S. Zelitch,81T. Zhao,82B. Zhou,63J. Zhu,72
M. Zielinski,71D. Zieminska,53L. Zivkovic,70V. Zutshi,51and E.G. Zverev39
(D0 Collaboration)
1Universidad de Buenos Aires, Buenos Aires, Argentina
2LAFEX, Centro Brasileiro de Pesquisas Fı ´sicas, Rio de Janeiro, Brazil
3Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
4Universidade Federal do ABC, Santo Andre ´, Brazil
5Instituto de Fı ´sica Teo ´rica, Universidade Estadual Paulista, Sa ˜o Paulo, Brazil
6Simon Fraser University, Burnaby, British Columbia, Canada;
and York University, Toronto, Ontario, Canada
7University of Science and Technology of China, Hefei, People’s Republic of China
8Universidad de los Andes, Bogota ´, Colombia
9Center for Particle Physics, Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic
10Czech Technical University in Prague, Prague, Czech Republic
11Center for Particle Physics, Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
12Universidad San Francisco de Quito, Quito, Ecuador
13LPC, Universite ´ Blaise Pascal, CNRS/IN2P3, Clermont, France
14LPSC, Universite ´ Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, Grenoble, France
15CPPM, Aix-Marseille Universite ´, CNRS/IN2P3, Marseille, France
16LAL, Universite ´ Paris-Sud, IN2P3/CNRS, Orsay, France
17LPNHE, IN2P3/CNRS, Universite ´s Paris VI and VII, Paris, France
18CEA, Irfu, SPP, Saclay, France
19IPHC, Universite ´ de Strasbourg, CNRS/IN2P3, Strasbourg, France
20IPNL, Universite ´ Lyon 1, CNRS/IN2P3, Villeurbanne, France and Universite ´ de Lyon, Lyon, France
21III. Physikalisches Institut A, RWTH Aachen University, Aachen, Germany
22Physikalisches Institut, Universita ¨t Bonn, Bonn, Germany
23Physikalisches Institut, Universita ¨t Freiburg, Freiburg, Germany
24II. Physikalisches Institut, Georg-August-Universita ¨t Go ¨ttingen, Go ¨ttingen, Germany
25Institut fu ¨r Physik, Universita ¨t Mainz, Mainz, Germany
26Ludwig-Maximilians-Universita ¨t Mu ¨nchen, Mu ¨nchen, Germany
27Fachbereich Physik, University of Wuppertal, Wuppertal, Germany
28Panjab University, Chandigarh, India
29Delhi University, Delhi, India
30Tata Institute of Fundamental Research, Mumbai, India
31University College Dublin, Dublin, Ireland
32Korea Detector Laboratory, Korea University, Seoul, Korea
33SungKyunKwan University, Suwon, Korea
34CINVESTAV, Mexico City, Mexico
35FOM-Institute NIKHEF and University of Amsterdam/NIKHEF, Amsterdam, The Netherlands
36Radboud University Nijmegen/NIKHEF, Nijmegen, The Netherlands
37Joint Institute for Nuclear Research, Dubna, Russia
38Institute for Theoretical and Experimental Physics, Moscow, Russia
39Moscow State University, Moscow, Russia
40Institute for High Energy Physics, Protvino, Russia
41Petersburg Nuclear Physics Institute, St. Petersburg, Russia
42Stockholm University, Stockholm, Sweden, and Uppsala University, Uppsala, Sweden
43Lancaster University, Lancaster, United Kingdom
PRL 104, 061804 (2010)
PHYSICALREVIEW LETTERS
week ending
12 FEBRUARY 2010
061804-2
Page 3
44Imperial College London, London SW7 2AZ, United Kingdom
45The University of Manchester, Manchester M13 9PL, United Kingdom
46University of Arizona, Tucson, Arizona 85721, USA
47University of California, Riverside, California 92521, USA
48Florida State University, Tallahassee, Florida 32306, USA
49Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
50University of Illinois at Chicago, Chicago, Illinois 60607, USA
51Northern Illinois University, DeKalb, Illinois 60115, USA
52Northwestern University, Evanston, Illinois 60208, USA
53Indiana University, Bloomington, Indiana 47405, USA
54Purdue University Calumet, Hammond, Indiana 46323, USA
55University of Notre Dame, Notre Dame, Indiana 46556, USA
56Iowa State University, Ames, Iowa 50011, USA
57University of Kansas, Lawrence, Kansas 66045, USA
58Kansas State University, Manhattan, Kansas 66506, USA
59Louisiana Tech University, Ruston, Louisiana 71272, USA
60University of Maryland, College Park, Maryland 20742, USA
61Boston University, Boston, Massachusetts 02215, USA
62Northeastern University, Boston, Massachusetts 02115, USA
63University of Michigan, Ann Arbor, Michigan 48109, USA
64Michigan State University, East Lansing, Michigan 48824, USA
65University of Mississippi, University, Mississippi 38677, USA
66University of Nebraska, Lincoln, Nebraska 68588, USA
67Rutgers University, Piscataway, New Jersey 08855, USA
68Princeton University, Princeton, New Jersey 08544, USA
69State University of New York, Buffalo, New York 14260, USA
70Columbia University, New York, New York 10027, USA
71University of Rochester, Rochester, New York 14627, USA
72State University of New York, Stony Brook, New York 11794, USA
73Brookhaven National Laboratory, Upton, New York 11973, USA
74Langston University, Langston, Oklahoma 73050, USA
75University of Oklahoma, Norman, Oklahoma 73019, USA
76Oklahoma State University, Stillwater, Oklahoma 74078, USA
77Brown University, Providence, Rhode Island 02912, USA
78University of Texas, Arlington, Texas 76019, USA
79Southern Methodist University, Dallas, Texas 75275, USA
80Rice University, Houston, Texas 77005, USA
81University of Virginia, Charlottesville, Virginia 22901, USA
82University of Washington, Seattle, Washington 98195, USA
(Received 25 January 2010; published 12 February 2010)
A search for the standard model Higgs boson is presented using events with two charged leptons and
large missing transverse energy selected from 5:4 fb?1of integrated luminosity in p? p collisions at
1:96 TeV collected with the D0 detector at the Fermilab Tevatron collider. No significant excess of events
above background predictions is found, and observed (expected) upper limits at 95% confidence level on
the rate of Higgs boson production are derived that are a factor of 1.55 (1.36) above the predicted standard
model cross section at mH¼ 165 GeV.
ffiffiffis
p
¼
DOI: 10.1103/PhysRevLett.104.061804PACS numbers: 14.80.Bn, 13.85.Rm
The Higgs mechanism, introduced in the standard model
(SM) toexplain electroweaksymmetrybreaking,predictsa
massive scalar (Higgs) boson, which has yet to be ob-
served. Direct searches at the CERN LEP eþe?collider
yielded a lower limit of 114.4 GeV for the SM Higgs boson
mass at 95% confidence level (C.L.) [1]. Indirect con-
straints obtained from fits to precision electroweak data,
when combined with direct searches at LEP, give an upper
bound of 186 GeVat 95% C.L. [2]. For a Higgs boson mass
(mH) close to 165 GeV the product of the SM Higgs boson
production cross section and the decay branching ratio into
two W bosons is maximal [3] and motivates the analysis
strategy.
In this Letter we present a search for Higgs bosons in
final states containing two charged leptons and missing
transverse energy (E 6
detector [4] and corresponding to an integrated luminosity
of 5:4 fb?1of p? p collisions at
T) using data collected with the D0
ffiffiffis
p
¼ 1:96 TeV. We con-
PRL 104, 061804 (2010)
PHYSICALREVIEW LETTERS
week ending
12 FEBRUARY 2010
061804-3
Page 4
sider final states containing either an electron and a posi-
tron (eþe?), an electron or a positron and a muon (e???),
or two muons (?þ??). Final states with tau leptons decay-
ing to e or ? or where hadronic tau decays are misidenti-
fied as electrons will also contribute to our search.
Previous searches in this channel have been performed
at the Tevatron by the CDFand the D0 collaborations [5,6].
This search represents an almost 20-fold increase in the D0
data set and considers additional Higgs boson production
modes leading to the dilepton and E 6
tion, the lepton acceptance is improved and the separation
of background and signal processes now utilizes an artifi-
cial neural network (NN) event classification technique.
The main Higgs boson production modes are via gluon
fusion and vector boson fusion. For these production
modes, this analysis considers only the Higgs boson decay
H ! WWð?Þ! ‘‘0??0ð‘;‘0¼ e;?;?Þ. Also considered is
Higgs boson production in association with a W or Z
boson, where Higgs boson decays to W=Z bosons and
leptons yield a dilepton plus E 6
with events considered in the analysis of WH ! Wb?b
and ZH ! Zb?b final states [7] is negligible. The CDF
collaboration is also reporting an updated search in this
channel [8].
The main background processes for this analysis are pair
production of heavy gauge bosons, Wðþjets=?Þ and
Z=??ðþjets=?Þ production, t? t production and multijet pro-
duction inwhichjets are misidentifiedas leptons.To model
the Wðþjets=?Þ and Z=??ðþjets=?Þ backgrounds we use
the ALPGEN event generator [9]. The signal and remaining
SM background processes are simulated with PYTHIA [10]
and all Monte Carlo (MC) samples are generated using
CTEQ6L1 [11] parton distribution functions (PDFs). In all
cases, event generation is followed by a detailed GEANT-
based [12] simulation of the D0 detector.
The background MC samples for inclusive W and Z=??
production are normalized to next-to-next-to-leading order
(NNLO) cross section predictions [13] calculated using
MRST 2004 NNLO PDFs [14]. The rate of t? t production
is normalized to a NNLO calculation [15] and diboson
rates (WW, WZ, and ZZ) are normalized to next-to-leading
order (NLO) cross sections [16]. The signal cross sections
are calculated at NNLO [17] (at NLO in the case of the
vector boson fusion process). The branching fractions for
the Higgs boson decay are determined using HDECAY [18].
The simulated Z boson transverse momentum (pT) dis-
tribution is modified to match the spectrum measured in
data [19]. In order to simulate the W boson pTdistribution,
the measured Z boson pTspectrum is multiplied by the
ratio of W to Z boson pTdistributions at NLO [20]. To
improve the modeling of WW background, the pTof the
diboson system is modified to match that obtained using
the MC@NLO generator [21], and the distribution of the
opening angle of the two leptons is modified to take into
account the contribution from gluon-gluon initiated pro-
Tsignature. In addi-
Tsignature. The overlap
cesses [22]. The Higgs boson transverse momentum
distribution in the PYTHIA-generated gluon fusion sample
is modified to match the distribution obtained using
SHERPA [23].
The backgroundduetomultijetproduction,inwhichjets
are misidentified as leptons, is determined from data. For
this purpose, a sample of like-charged dilepton events is
used in the ?þ??channel, corrected for like-charge con-
tributions from non-multijet processes. The eþe?and
e???channels use a sample of events with inverted lepton
quality requirements, scaled to match the yield and kine-
matics determined in the like-charge data.
This search is based on a sample of dilepton event
candidates collected using a mixture of single and dilepton
triggers whichachieveclose to 100% signal efficiency. The
identification of electron and muon candidates is based on
the criteria described in the previous search [6]. In addition
to the track isolation criterion, a constraint on the scalar
sum of charged particles transverse momentum (pT) in a
cone of radius R ¼
the muon track, an isolation requirement in the calorimeter
is applied. This is a requirement on the transverse energy
deposited in an annulus 0:1 < R < 0:4 around the muon
track. In the e???channel, each of these isolation pa-
rameters divided by the muon pTis required to be <0:15,
whereas in the ?þ??channel the ratio of the sum of these
two quantities divided by the muon pTis required to be
<0:4ð0:5Þ for the highest (next-to-highest) pTlepton ‘1
(‘2). In the ?þ??channel, the product of the isolation
ratios for both muons is required to be <0:06.
Electrons are required to have j?j < 2:5 (<2:0 in the
eþe?channel), and muons j?j < 2:0. Both leptons are
required to originate from the same interaction vertex
and to have opposite charges. Electrons must have pe
15 GeV, and muons p?
one of the two muons is required to have p?
addition, the dilepton invariant mass is required to exceed
15 GeV. Jets are reconstructed in the calorimeter using an
iterative midpoint cone algorithm [25] with a radius R ¼
0:5 and are required to have pjet
No jet-basedevent selection is applied,since the number of
jets in the event is used in the NN to help discriminate
signal from background. In the ?þ??channel, both
muons must be separated from any jet by R > 0:1. This
stage of the analysis is referred to as ‘‘preselection’’.
After preselection, the background is dominated by
Z=??production.This backgroundis suppressed byrequir-
ing E 6
Events are also removed if the E 6
by a mismeasurement of jet energies by requiring for the
scaled E 6
The minimum transverse mass, Mmin
smaller of the transverse masses MT[26] calculated from
the E 6
>20 GeV (>30 GeV in the eþe?channel) to suppress
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ð??Þ2þ ð??Þ2
p
¼ 0:5 [24] around
T>
T> 10 GeV. In the ?þ??channel
T> 20 GeV. In
T> 15 GeV and j?j < 2:4.
T> 20 GeV (>25 GeV in the ?þ??channel).
Twas likely produced
T[6], E 6
Sc
T> 6 in the eþe?and e???channels.
T
(defined as the
Tand either of the two leptons), is required to be
PRL 104, 061804 (2010)
PHYSICAL REVIEWLETTERS
week ending
12 FEBRUARY 2010
061804-4
Page 5
backgrounds where E 6
ton energy. Finally, events are rejected by requiring for the
azimuthal opening angle between the two leptons
??ð‘;‘Þ < 2:0 rad, because leptons from background pro-
cesses tend to be back-to-back in the transverse plane, in
contrast with those from a Higgs boson decay which,
owing to its zero spin, tend to move in the same direction.
This stage of the analysis is referred to as ‘‘final selection’’.
The dilepton invariant mass distribution after preselec-
tion for the combination of the three channels is shown in
Fig. 1(a). The ??ð‘;‘Þ distribution after final selection is
shown in Fig. 1(b). The contributions from the different
background processes in each of the three channels are
comparedwiththenumbersofeventsobservedindata after
preselection and after final selection in Table I. The total
systematic uncertainty (described below and in the supple-
mental material) after fitting is shown with correlations
appropriately incorporated.
Toriginates from mismeasured lep-
To improve the separation between signal and back-
ground, an optimized NN is used in each of the three
channels. Several well-modeled discriminant variables
are used as inputs to the NN: the transverse momenta of
the leptons, a variable indicating the quality of the leptons’
identification, the transverse momentum and invariant
mass of the dilepton system, Mmin
??ð‘1;E 6
and the scalar sum of the transverse momenta of the jets.
In each channel, separate NNs are trained for 18 test values
of mHfrom 115 to 200 GeV in steps of 5 GeV. The
combined distribution of the NN output for mH¼
165 GeV from all three channels is shown in Fig. 1(c).
The estimates for the expected number of background
and signal events depend on numerous factors, each in-
troducing a source of systematic uncertainty. Two types of
systematic uncertainties have been considered: those af-
fecting the absolute predicted event yield and those which
T, E 6
T, E 6
Sc
T, ??ð‘;‘Þ,
TÞ, ??ð‘2;E 6
TÞ, the number of identified jets,
Dilepton Mass (GeV)Dilepton Mass (GeV)Dilepton Mass (GeV)
000 50 5050 100100100 150150150 200200200
Events / 10 GeV
10
10 10
222
10 1010
333
10 1010
444
1010 10
555
10 1010
666
10 10 10
a)
-1
DØ 5.4 fb
) (rad) ) (rad) ) (rad)
l,l l,ll,l
( φ∆
( φ∆
( φ∆
0000.5 0.5 0.5111 1.51.51.5222
Events / 0.2 rad
10
10 10
222
10 10 10
333
10 1010
b)
-1
DØ 5.4 fb
NN Output NN OutputNN Output
000 0.2 0.20.20.4 0.4 0.40.6 0.60.6 0.80.8 0.8111
Events / 0.1
10
10 10
222
1010 10
333
10 1010
Data
Bkgd. syst.
Signal
Z+jets
Diboson
W+jets
Multijet
t t
c)
-1
DØ 5.4 fb
FIG. 1 (color online).
network output after final selection. The signal is shown for mH¼ 165 GeV. The systematic uncertainty is shown after fitting (see text
for details).
(a) The dilepton invariant mass after preselection; (b) the ??ð‘;‘Þ angle after final selection; and (c) the neural
TABLE I.
uncertainty after fitting is shown for all samples at final selection.
Expected and observed event yields in each channel after preselection and at the final selection. The systematic
e???
eþe?
?þ??
PreselectionFinal selection PreselectionFinal selection PreselectionFinal selection
Z=??! eþe?
Z=??! ?þ??
Z=??! ?þ??
t? t
W þ jets=?
WW
WZ
ZZ
Multijet
Signal (mmH¼ 165 GeV)
Total background
Data
120
89
3871
312
267
455
23.6
<0:1
4:3 ? 0:3
7:1 ? 0:5
93:8 ? 8:3
112 ? 9
165 ? 6
7:6 ? 0:2
0:6 ? 0:1
6:4 ? 2:5
13:5 ? 1:5
397 ? 14
390
274886
158 ? 13
-
0:7 ? 0:1
47:0 ? 4:4
122 ? 11
73:9 ? 6:4
11:5 ? 1:0
9:3 ? 0:9
1:0 ? 0:1
7:2 ? 0:8
423 ? 19
421
--
- 373582
2659
184
236
272
171
147
408
1247 ? 37
12:0 ? 0:7
74:6 ? 6:8
91:5 ? 6:5
107 ? 9
21:5 ? 2:0
18:0 ? 1:8
53:8 ? 10:3
9:0 ? 1:0
1625 ? 41
1613
1441
159
308
202
137
1 17
1370
11.2
5.4
430
18.8 12.7
5573
5566
278620
278277
377659
384083
PRL 104, 061804 (2010)
PHYSICALREVIEW LETTERS
week ending
12 FEBRUARY 2010
061804-5
Page 6
also affect the shape of the NN output distribution. The
most significant systematic uncertainties affecting the nor-
malization of the NN output (quoted as a percentage of the
yield per signal or background process) are: lepton recon-
struction efficiencies (3%–6%), lepton momentum calibra-
tion (1%–3%), theoretical cross section (including PDF,
factorization and renormalization scale uncertainties: 7%
for diboson, 10% for t? t 7% for W=ZðþjetsÞ, 11% for Higgs
signal), modeling of multijet background (2%–15%), and
integrated luminosity (6.1%). The most important sources
affecting the NN output shape are: jet reconstruction effi-
ciency (1%–3%), jet energy scale calibration (1%–5%), jet
energy resolution (2%), and modeling of pTðWWÞ, pTðHÞ,
and pTðZÞ (1%–5%). The systematic uncertainty on the
modeling of pTðWWÞ and pTðHÞ has been determined by
comparing the pTdistributions of PYTHIA, SHERPA, and
MC@NLO, and the uncertainty on pTðZÞ from a comparison
of the shape of the NN distribution between data and MC
predictions in a Z=??enriched control sample. The SHERPA
and MC@NLO predictions agree well with each other and
generate harder pTspectra than PYTHIA [27]. The uncer-
tainty on ??ð‘;‘Þ for the WW background is taken as 30%
of the correction to the PYTHIA angular distribution as
estimated in Ref. [22], leading to a relative uncertainty at
the subpercent level. Appropriate correlations of system-
atic uncertainties between different channels, between dif-
ferent backgrounds, and between backgrounds and signal
are included.
After all selections, no significant excess of signal-like
events is observed for any test value of mH. Thus the NN
output distributions are used to set upper limits on the
Higgs boson production cross section, assuming the SM-
predicted ratio of production cross sections and Higgs
decay branching ratios. Upper limits are set using the three
search channels combined using a modified frequentist
method with a log-likelihood ratio (LLR) test statistic
[28]. To minimize the degrading effects of systematics on
the search sensitivity, the signal and different background
sources contributions are fitted to the data observations by
maximizing a likelihood function over the systematic un-
certainties for both the background-only and signal þ
background hypotheses [29]. Figure 2(a) shows a compari-
son of the NN distribution between background-subtracted
data and the expected signal for mH¼ 165 GeV hypothe-
sis. The background prediction and its uncertainties have
been determined from the fit to data under the background-
only hypothesis. The LLR distribution as a function of mH
is shown in Fig. 2(b) demonstrating the overall consistency
of the data with the background-only hypothesis in the full
mHrange considered. Table II and Fig. 2(c) present the
expected and observed upper limits as a ratio to the ex-
pected SM cross section. Assuming mH¼ 165 GeV, the
NN Output
0 0.2 0.40.6 0.81
Events / 0.1
-40
-30
-20
-10
0
10
20
30
40
50
Data
Signal
Bkgd. 1 s.d.
±
a)
DØ 5.4 fb
-1
(GeV)
H
(GeV)
H
mm
120 130 140 150 160 170 180 190 200 120 130 140 150 160 170 180 190 200
LLR
-4
-4
-2
-2
0
0
2
2
4
4
6
6
8
8
10
10
b)
DØ 5.4 fb
-1
1 s.d.
2 s.d.
±
B
±
B
LLR
LLR
LLR
LLR
LLR
B
S+B
OBS
(GeV)
H
(GeV)
H
mm
120 130 140 150 160 170 180 190 200120 130 140 150 160 170 180 190 200
95% C.L. Limit / SM
11
1010
-1
DØ 5.4 fb
c)
Observed Limit
Expected Limit
Expected
Expected
1 s.d.
2 s.d.
±
±
Standard Model = 1.0
FIG. 2 (color online).
function of the NN output for mH¼ 165 GeV. Also shown is the ?1 standard deviation (s.d.) band on the total background after
fitting. (b) Observed LLR (solid line), expected LLR for background-only hypothesis (dashed line), and signal þ background
hypothesis (dotted line). (c) Upper limit on Higgs boson production cross section at 95% C.L. expressed as a ratio to the SM cross
section. The one and two s.d. bands around the curve corresponding to the background-only hypothesis are also shown.
(a) Data after subtracting the fitted background (points) and SM signal expectation (filled histogram) as a
TABLE II.
cross section predicted by the SM for a range of test Higgs boson masses.
Expected and observed upper limits at 95% C.L. for Higgs boson production cross section expressed as a ratio to the
mH(GeV) 115120 125130 135 140145 150155160165 170175 180185 190195 200
Limit (exp.)
Limit (obs.)
14.9
20.8
9.74
13.6
7.20
8.81
5.40
6.63
4.23
6.41
3.48
5.21
3.07
3.94
2.58
3.29
2.02
3.25
1.43
1.82
1.36
1.55
1.65
1.96
2.06
1.89
2.59
2.11
3.28
3.17
4.20
3.27
5.08
5.77
6.23
5.53
PRL 104, 061804 (2010)
PHYSICALREVIEW LETTERS
week ending
12 FEBRUARY 2010
061804-6
Page 7
observed (expected) upper limit at 95% C.L. on Higgs
boson production is a factor of 1.55 (1.36) times the SM
cross section, representing an improvement in sensitivity
of over a factor of 6 relative to our previous publication [6],
larger than expected from the luminosity increase alone.
Auxiliary material is provided in [30].
We thank the staffs at Fermilab and collaborating insti-
tutions, and acknowledge support from the DOE and NSF
(USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom
and RFBR (Russia); CNPq, FAPERJ, FAPESP and
FUNDUNESP(Brazil);DAE
Colciencias (Colombia); CONACyT (Mexico); KRF and
KOSEF (Korea); CONICET and UBACyT (Argentina);
FOM (The Netherlands); STFC and the Royal Society
(United Kingdom); MSMT and GACR (Czech Republic);
CRC Program, CFI, NSERC and WestGrid Project
(Canada); BMBF and DFG (Germany); SFI (Ireland);
The Swedish Research Council (Sweden); and CAS and
CNSF (China).
andDST (India);
*Visitor from Augustana College, Sioux Falls, SD, USA.
†Visitor from The University of Liverpool, Liverpool, UK.
‡Visitor from SLAC, Menlo Park, CA, USA.
xVisitor from ICREA/IFAE, Barcelona, Spain.
kVisitor from Centro de Investigacion en Computacion—
IPN, Mexico City, Mexico.
{Visitor from ECFM, Universidad Autonoma de Sinaloa,
Culiaca ´n, Mexico.
**Visitor from Universita ¨t Bern, Bern, Switzerland.
[1] R. Barate et al., Phys. Lett. B 565, 61 (2003).
[2] LEP Electroweak Working Group, Tevatron Electroweak
Working Group, SLD Electroweak and Heavy Flavour
Groups, arXiv:0911.2604.
[3] T. Han, A.S. Turcot, and R-J. Zhang, Phys. Rev. D 59,
093001 (1999); M. Carena et al. (Higgs Working Group
Collaboration), arXiv:hep-ph/0010338.
[4] V. Abazov et al. (D0 Collaboration), Nucl. Instrum.
Methods Phys. Res., Sect. A 565, 463 (2006); M.
Abolins et al., Nucl. Instrum. Methods Phys. Res., Sect.
A 584, 75 (2008); R. Angstadt et al., arXiv:0911.2522
[Nucl. Instrum. Methods Phys. Res. A (to be published)].
[5] T. Aaltonen et al., Phys. Rev. Lett. 102, 021802 (2009).
[6] V. Abazov et al. (D0 Collaboration), Phys. Rev. Lett. 96,
011801 (2006).
[7] V. Abazov et al. (D0 Collaboration), Phys. Rev. Lett. 102,
051803 (2009); Phys. Lett. B 655, 209 (2007).
[8] T. Aaltonen et al. (CDF Collaboration), this issue, Phys.
Rev. Lett. 104, 061803 (2010).
[9] M.L. Mangano et al., J. High Energy Phys. 07 (2003) 001;
we use version 2.11.
[10] T. Sjo ¨strand et al., Comput. Phys. Commun. 135, 238
(2001); we use version 6.323 or later.
[11] J. Pumplin et al., J. High Energy Phys. 07 (2002) 012.
[12] R. Brun and F. Carminati, CERN Program Library Long
Writeup W5013, 1993 (unpublished).
[13] R. Hamberg, W.L. van Neerven, and T. Matsuura, Nucl.
Phys. B 359, 343 (1991) [644, 403 (2002)].
[14] A.D. Martin, R.G. Roberts, W.J. Stirling, and R.S.
Thorne, Phys. Lett. B 604, 61 (2004).
[15] S. Moch and P. Uwer, Phys. Rev. D 78, 034003 (2008); we
use ?ðttÞ ¼ 7:88 pb.
[16] J.M. Campbell and R.K. Ellis, Phys. Rev. D 60, 113006
(1999); we use ?ðWWÞ ¼ 11:66 pb, ?ðWZÞ ¼ 3:45 pb,
and ?ðZZÞ ¼ 1:37 pb.
[17] C. Anastasiou, R. Boughezal, and F. Petriello, J. High
Energy Phys. 04 (2009) 003; D. de Florian and M.
Grazzini, Phys.Lett.
Assamagan et al., arXiv:hep-ph/0406152; O. Brein, A.
Djouadi, and R. Harlander, Phys. Lett. B 579, 149
(2004); M.L. Ciccolini, S. Dittmaier, and M. Kra ¨mer,
Phys. Rev. D 68, 073003 (2003); E.L. Berger and J.
Campbell, Phys. Rev. D 70, 073011 (2004).
[18] A. Djouadi, J. Kalinowski, and M. Spira, Comput. Phys.
Commun. 108, 56 (1998).
[19] V. Abazov et al. (D0 Collaboration), Phys. Rev. Lett. 100,
102002 (2008).
[20] K. Melnikov and F. Petriello, Phys. Rev. D 74, 114017
(2006).
[21] S. Frixione and B.R. Webber, J. High Energy Phys. 06
(2002) 029.
[22] T. Binoth, M. Ciccoli, N. Kauer, and M. Kra ¨mer, J. High
Energy Phys. 03 (2005) 065; J. High Energy Phys. 12
(2006) 046.
[23] T. Gleisberg et al., J. High Energy Phys. 02 (2004) 056.
[24] The D0 coordinate system is cylindrical with the z axis in
the direction of the proton beam. In this frame, the angle ?
is the azimuthal angle, and ? is the polar angle. The
pseudorapidity ? is defined as ? ¼ ?ln½tanð?=2Þ?.
[25] G. Blazey et al., arXiv:hep-ex/0005012v2.
[26] J. Smith, W.L. van Neerven, and J.A.M. Vermaseren,
Phys. Rev. Lett. 50, 1738 (1983).
[27] T. Gleisberg, F. Krauss, A. Schalicke, S. Schumann, J.C.
Winter, Phys. Rev. D 72, 034028 (2005).
[28] T. Junk, Nucl. Instrum. Methods Phys. Res., Sect. A 434,
435 (1999); A. Read, J. Phys. G 28, 2693 (2002).
[29] W. Fisher, FERMILAB Report no. FERMILAB-TM-
2386-E.
[30] See supplementarymaterial
supplemental/10.1103/PhysRevLett.104.061804 for the
distribution of the quantities used in the event selection
and of the inputs of the NN.
B
674, 291 (2009); K.A.
at http://link.aps.org/
PRL 104, 061804 (2010)
PHYSICALREVIEW LETTERS
week ending
12 FEBRUARY 2010
061804-7
View other sources
Hide other sources
-
Available from Lars Sonnenschein · 29 Jan 2013
-
Available from uva.nl