Navegar

Colección

Datos Estadísticas

Artículo

Estamos trabajando para incorporar este artículo al repositorio
Consulte el artículo en la página del editor
Consulte la política de Acceso Abierto del editor

Abstract:

An analysis is presented of events containing jets including at least one b-tagged jet, sizeable missing transverse momentum, and at least two leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. A data sample with an integrated luminosity of 20.3 fb −1 of pp collisions at √s = 8 TeV recorded by the ATLAS detector at the Large Hadron Collider is used. Standard Model processes rarely produce these final states, but there are several models of physics beyond the Standard Model that predict an enhanced rate of production of such events; the ones considered here are production of vector-like quarks, enhanced four-top-quark production, pair production of chiral b′-quarks, and production of two positively charged top quarks. Eleven signal regions are defined; subsets of these regions are combined when searching for each class of models. In the three signal regions primarily sensitive to positively charged top quark pair production, the data yield is consistent with the background expectation. There are more data events than expected from background in the set of eight signal regions defined for searching for vector-like quarks and chiral b′-quarks, but the significance of the discrepancy is less than two standard deviations. The discrepancy reaches 2.5 standard deviations in the set of five signal regions defined for searching for four-top-quark production. The results are used to set 95% CL limits on various models. © 2015, The Author(s).

Registro:

Documento: Artículo
Título:Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector
Autor:The ATLAS collaboration et al.
Este artículo contiene 2825 autores, consultelos en el artículo en formato pdf.
Filiación: Este artículo contiene 2825 autores con sus filiaciones, consultelas en el artículo en formato pdf.
Palabras clave:Beyond Standard Model; chiral b’; Exotics; four-top-production; Hadron-Hadron Scattering; Lepton production; same charge top pair; vector-like quarks
Año:2015
Volumen:2015
Número:10
Página de inicio:1
Página de fin:51
DOI: http://dx.doi.org/10.1007/JHEP10(2015)150
Título revista:Journal of High Energy Physics
Título revista abreviado:J. High Energy Phys.
ISSN:11266708
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_11266708_v2015_n10_p1_TheATLAScollaboration

Referencias:

  • Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC, Phys. Lett.B 716 (2012) 1; Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Phys. Lett.B 716 (2012) 30; Dobrescu, B.A., Hill, C.T., Electroweak symmetry breaking via top condensation seesaw (1998) Phys. Rev. Lett., 81, p. 2634. , [hep-ph/9712319] [INSPIRE]
  • Chivukula, R.S., Dobrescu, B.A., Georgi, H., Hill, C.T., Top quark seesaw theory of electroweak symmetry breaking (1999) Phys. Rev., 59, p. 075003. , [hep-ph/9809470] [INSPIRE]
  • He, H.-J., Hill, C.T., Tait, T.M.P., Top quark seesaw, vacuum structure and electroweak precision constraints (2002) Phys. Rev., 65, p. 055006. , [hep-ph/0108041] [INSPIRE]
  • Hill, C.T., Simmons, E.H., Strong dynamics and electroweak symmetry breaking, Phys. Rept.381 (2003) 235 390 (2004) 553]; Contino, R., Da Rold, L., Pomarol, A., Light custodians in natural composite Higgs models (2007) Phys. Rev., 75, p. 055014. , [hep-ph/0612048] [INSPIRE]
  • Anastasiou, C., Furlan, E., Santiago, J., Realistic composite Higgs models (2009) Phys. Rev., 79, p. 075003. , [arXiv:0901.2117] [INSPIRE]
  • Kong, K., McCaskey, M., Wilson, G.W., Multi-lepton signals from the top-prime quark at the LHC (2012) JHEP, 4, p. 079. , [arXiv:1112.3041] [INSPIRE]
  • Carmona, A., Chala, M., Santiago, J., New Higgs production mechanism in composite Higgs models (2012) JHEP, 7, p. 049. , [arXiv:1205.2378] [INSPIRE]
  • Gillioz, M., Grober, R., Grojean, C., Muhlleitner, M., Salvioni, E., Higgs low-energy theorem (and its corrections) in composite models (2012) JHEP, 10, p. 004. , [arXiv:1206.7120] [INSPIRE]
  • Davidson, A., Wali, K.C., Family mass hierarchy from universal seesaw mechanism (1988) Phys. Rev. Lett., 60, p. 1813. , [INSPIRE]
  • Babu, K.S., Mohapatra, R.N., A solution to the strong CP problem without an axion (1990) Phys. Rev., 41, p. 1286. , [INSPIRE]
  • Grinstein, B., Redi, M., Villadoro, G., Low scale flavor gauge symmetries (2010) JHEP, 11, p. 067. , [arXiv:1009.2049] [INSPIRE]
  • Guadagnoli, D., Mohapatra, R.N., Sung, I., Gauged flavor group with left-right symmetry (2011) JHEP, 4, p. 093. , [arXiv:1103.4170] [INSPIRE]
  • Arkani-Hamed, N., Cohen, A.G., Katz, E., Nelson, A.E., The littlest Higgs (2002) JHEP, 7, p. 034. , [hep-ph/0206021] [INSPIRE]
  • Han, T., Logan, H.E., McElrath, B., Wang, L.-T., Phenomenology of the little Higgs model (2003) Phys. Rev., 67, p. 095004. , [hep-ph/0301040] [INSPIRE]
  • Perelstein, M., Peskin, M.E., Pierce, A., Top quarks and electroweak symmetry breaking in little Higgs models (2004) Phys. Rev., 69, p. 075002. , [hep-ph/0310039] [INSPIRE]
  • Schmaltz, M., Tucker-Smith, D., Little Higgs theories (2005) Ann. Rev. Nucl. Part. Sci., 55, p. 229. , [hep-ph/0502182] [INSPIRE]
  • Carena, M., Hubisz, J., Perelstein, M., Verdier, P., Collider signatures for new T-parity-odd quarks in little Higgs models (2007) Phys. Rev., 75, p. 091701. , [hep-ph/0610156] [INSPIRE]
  • Matsumoto, S., Moroi, T., Tobe, K., Testing the littlest Higgs model with T-parity at the Large Hadron Collider (2008) Phys. Rev., 78, p. 055018. , [arXiv:0806.3837] [INSPIRE]
  • Aguilar-Saavedra, J.A., Benbrik, R., Heinemeyer, S., Pérez-Victoria, M., Handbook of vectorlike quarks: mixing and single production (2013) Phys. Rev., 88, p. 094010. , [arXiv:1306.0572] [INSPIRE]
  • J.A. Aguilar-Saavedra, Effects of mixing with quark singlets, Phys. Rev.D 67 (2003) 035003 D 69 (2004) 099901; Okada, Y., Panizzi, L., LHC signatures of vector-like quarks (2013) Adv. High Energy Phys., 2013, p. 364936. , [arXiv:1207.5607] [INSPIRE]
  • Aguilar-Saavedra, J.A., Identifying top partners at LHC (2009) JHEP, 11, p. 030. , [arXiv:0907.3155] [INSPIRE]
  • Czakon, M., Fiedler, P., Mitov, A., Total top-quark pair-production cross section at hadron colliders through O(α s 4 ) (2013) Phys. Rev. Lett., 110, p. 252004. , [arXiv:1303.6254] [INSPIRE]
  • Czakon, M., Mitov, A., Top++: a program for the calculation of the top-pair cross-section at hadron colliders (2014) Comput. Phys. Commun., 185, p. 2930. , [arXiv:1112.5675] [INSPIRE]
  • Barger, V.D., Stange, A.L., Phillips, R.J.N., Four heavy quark hadroproduction (1991) Phys. Rev., 44, p. 1987. , [INSPIRE]
  • Barger, V., Keung, W.-Y., Yencho, B., Triple-top signal of new physics at the LHC (2010) Phys. Lett., 687, p. 70. , [arXiv:1001.0221] [INSPIRE]
  • Lillie, B., Shu, J., Tait, T.M.P., Top compositeness at the Tevatron and LHC (2008) JHEP, 4, p. 087. , [arXiv:0712.3057] [INSPIRE]
  • Pomarol, A., Serra, J., Top quark compositeness: feasibility and implications (2008) Phys. Rev., 78, p. 074026. , [arXiv:0806.3247] [INSPIRE]
  • Degrande, C., Gerard, J.-M., Grojean, C., Maltoni, F., Servant, G., Non-resonant new physics in top pair production at hadron colliders (2011) JHEP, 3, p. 125. , [arXiv:1010.6304] [INSPIRE]
  • Guchait, M., Mahmoudi, F., Sridhar, K., Associated production of a Kaluza-Klein excitation of a gluon with a tt¯ pair at the LHC (2008) Phys. Lett., 666, p. 347. , [arXiv:0710.2234] [INSPIRE]
  • Plehn, T., Tait, T.M.P., Seeking sgluons (2009) J. Phys., 36, p. 075001. , [arXiv:0810.3919] [INSPIRE]
  • Choi, S.Y., Drees, M., Kalinowski, J., Kim, J.M., Popenda, E., Zerwas, P.M., Color-octet scalars of N = 2 supersymmetry at the LHC (2009) Phys. Lett., 672, p. 246. , [arXiv:0812.3586] [INSPIRE]
  • Kilic, C., Okui, T., Sundrum, R., Vectorlike confinement at the LHC (2010) JHEP, 2, p. 018. , [arXiv:0906.0577] [INSPIRE]
  • Kilic, C., Okui, T., Sundrum, R., Colored resonances at the Tevatron: phenomenology and discovery potential in multijets (2008) JHEP, 7, p. 038. , [arXiv:0802.2568] [INSPIRE]
  • Burdman, G., Dobrescu, B.A., Pónton, E., Resonances from two universal extra dimensions (2006) Phys. Rev., 74, p. 075008. , [hep-ph/0601186] [INSPIRE]
  • Calvet, S., Fuks, B., Gris, P., Valéry, L., Searching for sgluons in multitop events at a center-of-mass energy of 8 TeV (2013) JHEP, 4, p. 043. , [arXiv:1212.3360] [INSPIRE]
  • Beck, L., Blekman, F., Dobur, D., Fuks, B., Keaveney, J., Mawatari, K., Probing top-philic sgluons with LHC Run I data (2015) Phys. Lett., 746, p. 48. , [arXiv:1501.07580] [INSPIRE]
  • Goncalves-Netto, D., Lopez-Val, D., Mawatari, K., Plehn, T., Wigmore, I., Sgluon pair production to next-to-leading order (2012) Phys. Rev., 85, p. 114024. , [arXiv:1203.6358] [INSPIRE]
  • Cacciapaglia, G., Deandrea, A., Llodra-Perez, J., A dark matter candidate from Lorentz invariance in 6D (2010) JHEP, 3, p. 083. , [arXiv:0907.4993] [INSPIRE]
  • Arbey, A., Cacciapaglia, G., Deandrea, A., Kubik, B., Dark matter in a twisted bottle (2013) JHEP, 1, p. 147. , [arXiv:1210.0384] [INSPIRE]
  • Frampton, P.H., Hung, P.Q., Sher, M., Quarks and leptons beyond the third generation (2000) Phys. Rept., 330, p. 263. , [hep-ph/9903387] [INSPIRE]
  • Holdom, B., The discovery of the fourth family at the LHC: what if? (2006) JHEP, 8, p. 076. , [hep-ph/0606146] [INSPIRE]
  • Hung, P.Q., Nonsupersymmetric SU(5) resuscitated by new quarks and leptons (1998) Phys. Rev. Lett., 80, p. 3000. , [hep-ph/9712338] [INSPIRE]
  • Hou, W.-S., Source of CP-violation for the baryon asymmetry of the universe (2009) Chin. J. Phys., 47, p. 134. , [arXiv:0803.1234] [INSPIRE]
  • Eberhardt, O., Impact of a Higgs boson at a mass of 126 GeV on the Standard Model with three and four fermion generations (2012) Phys. Rev. Lett., 109, p. 241802. , [arXiv:1209.1101] [INSPIRE]
  • Djouadi, A., Lenz, A., Sealing the fate of a fourth generation of fermions (2012) Phys. Lett., 715, p. 310. , [arXiv:1204.1252] [INSPIRE]
  • Eberhardt, O., Joint analysis of Higgs decays and electroweak precision observables in the Standard Model with a sequential fourth generation (2012) Phys. Rev., 86, p. 013011. , [arXiv:1204.3872] [INSPIRE]
  • Eberhardt, O., Lenz, A., Menzel, A., Nierste, U., Wiebusch, M., Status of the fourth fermion generation before ICHEP2012: Higgs data and electroweak precision observables (2012) Phys. Rev., 86, p. 074014. , [arXiv:1207.0438] [INSPIRE]
  • Denner, A., Higgs production and decay with a fourth Standard-Model-like fermion generation (2012) Eur. Phys. J., 72, p. 1992. , [arXiv:1111.6395] [INSPIRE]
  • Passarino, G., Sturm, C., Uccirati, S., Complete electroweak corrections to Higgs production in a Standard Model with four generations at the LHC (2011) Phys. Lett., 706, p. 195. , [arXiv:1108.2025] [INSPIRE]
  • Bar-Shalom, S., Geller, M., Nandi, S., Soni, A., Two Higgs doublets, a 4 th generation and a 125 GeV Higgs: a review (2013) Adv. High Energy Phys., 2013, p. 672972. , [arXiv:1208.3195] [INSPIRE]
  • Aguilar-Saavedra, J.A., Pérez-Victoria, M., No like-sign tops at Tevatron: constraints on extended models and implications for the tt asymmetry (2011) Phys. Lett., 701, p. 93. , [arXiv:1104.1385] [INSPIRE]
  • Berger, E.L., Cao, Q.-H., Chen, C.-R., Li, C.S., Zhang, H., Top quark forward-backward asymmetry and same-sign top quark pairs (2011) Phys. Rev. Lett., 106, p. 201801. , [arXiv:1101.5625] [INSPIRE]
  • M. Buchkremer, G. Cacciapaglia, A. Deandrea and L. Panizzi, Feynrules top FCNC model webpage; Search for same-sign top-quark production and fourth-generation down-type quarks in pp collisions at s=7 TeV with the ATLAS detector, JHEP 04 (2012) 069; Search for new physics in events with same-sign dileptons and jets in pp collisions at s=8 TeV, JHEP 01 (2014) 163 01 (2015) 014; Search for top-quark partners with charge 5/3 in the same-sign dilepton final state, Phys. Rev. Lett.112 (2014) 171801; Inclusive search for a vector-like T quark with charge 2/3 in pp collisions at s=8 TeV, Phys. Lett.B 729 (2014) 149; Search for supersymmetry at s = 8 TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector, JHEP 06 (2014) 035; The ATLAS experiment at the CERN Large Hadron Collider, 2008 JINST 3 S08003 []; Martin, A.D., Stirling, W.J., Thorne, R.S., Watt, G., Parton distributions for the LHC (2009) Eur. Phys. J., 63, p. 189. , [arXiv:0901.0002] [INSPIRE]
  • Sjöstrand, T., Mrenna, S., Skands, P.Z., PYTHIA 6.4 physics and manual (2006) JHEP, 5, p. 026. , [hep-ph/0603175] [INSPIRE]
  • Alwall, J., Herquet, M., Maltoni, F., Mattelaer, O., Stelzer, T., MadGraph 5: going beyond (2011) JHEP, 6, p. 128. , [arXiv:1106.0522] [INSPIRE]
  • Pumplin, J., Stump, D.R., Huston, J., Lai, H.L., Nadolsky, P.M., Tung, W.K., New generation of parton distributions with uncertainties from global QCD analysis (2002) JHEP, 7, p. 012. , [hep-ph/0201195] [INSPIRE]
  • Sjöstrand, T., Mrenna, S., Skands, P.Z., A brief introduction to PYTHIA 8.1 (2008) Comput. Phys. Commun., 178, p. 852. , [arXiv:0710.3820] [INSPIRE]
  • P. Meade and M. Reece, BRIDGE: Branching Ratio Inquiry/Decay Generated Events, []; Cacciapaglia, G., Deandrea, A., Llodra-Perez, J., The universal real projective plane: LHC phenomenology at one loop (2011) JHEP, 10, p. 146. , [arXiv:1104.3800] [INSPIRE]
  • J.A. Aguilar-Saavedra, Effective four-fermion operators in top physics: a roadmap, Nucl. Phys.B 843 (2011) 638 B 851 (2011) 443; Gleisberg, T., Event generation with SHERPA 1.1 (2009) JHEP, 2, p. 007. , [arXiv:0811.4622] [INSPIRE]
  • Lai, H.-L., New parton distributions for collider physics (2010) Phys. Rev., 82, p. 074024. , [arXiv:1007.2241] [INSPIRE]
  • S. Agostinelli et al., GEANT4: a simulation toolkit, Nucl. Instrum. Meth.A 506 (2003) 250 []; The ATLAS simulation infrastructure, Eur. Phys. J.C 70 (2010) 823; The simulation principle and performance of the ATLAS fast calorimeter simulation FastCaloSim, ATL-PHYS-PUB-2010-013, CERN (2010) Geneva Switzerland
  • LHC proton-proton collision data, ATLAS-CONF-2014-032, CERN (2012) Geneva Switzerland (2014)
  • Rehermann, K., Tweedie, B., Efficient identification of boosted semileptonic top quarks at the LHC (2011) JHEP, 3, p. 059. , [arXiv:1007.2221] [INSPIRE]
  • Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data, Eur. Phys. C 74 (2014) 3130; Cacciari, M., Salam, G.P., Soyez, G., The anti-k t jet clustering algorithm (2008) JHEP, 4, p. 063. , [arXiv:0802.1189] [INSPIRE]
  • Cacciari, M., Salam, G.P., Dispelling the N 3 myth for the k t jet-finder (2006) Phys. Lett., 641, p. 57. , [hep-ph/0512210] [INSPIRE]
  • Cacciari, M., Salam, G.P., Soyez, G., FastJet user manual (2012) Eur. Phys. J., 72, p. 1896. , [arXiv:1111.6097] [INSPIRE]
  • Jet energy measurement with the ATLAS detector in proton-proton collisions at √s=7 TeV, Eur. Phys. J.C 73 (2013) 2304; Commissioning of the ATLAS high-performance b-tagging algorithms in the 7 TeV collision data, ATLAS-CONF-2011-102, CERN (2011) Geneva Switzerland
  • Campbell, J.M., Ellis, R.K., tt¯ W± production and decay at NLO (2012) JHEP, 7, p. 052. , [arXiv:1204.5678] [INSPIRE]
  • Improved luminosity determination in pp collisions at √s =7 TeV using the ATLAS detector at the LHC, Eur. Phys. J.C 73 (2013) 2518; Junk, T., Confidence level computation for combining searches with small statistics (1999) Nucl. Instrum. Meth., 434, p. 435. , [hep-ex/9902006] [INSPIRE]
  • Read, A.L., Presentation of search results: the CL s technique (2002) J. Phys., 28, p. 2693. , [INSPIRE]
  • Contino, R., Servant, G., Discovering the top partners at the LHC using same-sign dilepton final states (2008) JHEP, 6, p. 026. , [arXiv:0801.1679] [INSPIRE]
  • http://feynrules.irmp.ucl.ac.be/wiki/VLQ_xtdoubletvl, M. Buchkremer, G. Cacciapaglia, A. Deandrea and L. Panizzi, Feynrules exotic (X, T) doublet model webpage; Buchkremer, M., Cacciapaglia, G., Deandrea, A., Panizzi, L., Model independent framework for searches of top partners (2013) Nucl. Phys., 876, p. 376. , [arXiv:1305.4172] [INSPIRE]

Citas:

---------- APA ----------
(2015) . Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector. Journal of High Energy Physics, 2015(10), 1-51.
http://dx.doi.org/10.1007/JHEP10(2015)150
---------- CHICAGO ----------
The ATLAS collaboration. "Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector" . Journal of High Energy Physics 2015, no. 10 (2015) : 1-51.
http://dx.doi.org/10.1007/JHEP10(2015)150
---------- MLA ----------
The ATLAS collaboration. "Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector" . Journal of High Energy Physics, vol. 2015, no. 10, 2015, pp. 1-51.
http://dx.doi.org/10.1007/JHEP10(2015)150
---------- VANCOUVER ----------
The ATLAS collaboration. Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector. J. High Energy Phys. 2015;2015(10):1-51.
http://dx.doi.org/10.1007/JHEP10(2015)150