Measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P)) in pp collisions at s=8TeV

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Title:	Measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P)) in pp collisions at s=8TeV
Authors:	余欣珊;Levine, Aaron;Poehlsen, Jennifer;Apresyan, Artur;Bagliesi, Giuseppe;Velkovska, Julia;Varelas, Nikos;Seva, Tomislav;Innocente, Vincenzo;Swain, Sanjay Kumar;Hadjiiska, Roumyana;Gascon, Susan;Geiser, Achim;Spalding, William J;Shukla, Prashant;Colaleo, Anna;Piotrzkowski, Krzysztof;Steinbrück, Georg;Avetisyan, Aram;Rose, Anthony;Li, Qiang;Elliott-Peisert, Anna;Farrell, Chris;Mittal, Monika;Pant, Lalit Mohan;Tricomi, Alessia;Martinez, German;Cockerill, David JA;Ferencek, Dinko;Marchesini, Ivan;Haas, Jeff;Christopher, Grant;Tosi, Nicolò;Ekmedzic, Marko;Lu, Ying;Brooke, James John;Mott, Alexander;Ahmad, Ashfaq;Mohanty, Ajit Kumar;Spiropulu, Maria;De Moraes Gregores, Eduardo;Malcles, Julie;Dewanjee, Ram Krishna;Tamponi, Umberto;Jain, Shilpi;Luyckx, Sten;Danielson, Thomas;Fabbri, Fabrizio;Berry, Edmund;Chwalek, Thorsten;Dupont-Sagorin, Niels;Paktinat Mehdiabadi, Saeid;Szillasi, Zoltan;Bauer, Gerry;Woods, Nathaniel;Hatakeyama, Kenichi;Kazana, Malgorzata;Dumanoglu, Isa;Frueboes, Tomasz;Bachtis, Michail;Costa, Salvatore;Gerosa, Raffaele;Letts, James;Kim, Tae Jeong;Saka, Halil;Skatchkov, Nikolai;Piparo, Danilo;Van Mechelen, Pierre;Castaneda Hernandez, Alfredo;Fulcher, Jonathan;West, Christopher;Gomez, Gervasio;Gninenko, Sergei;Dinardo, Mauro Emanuele;Ptochos, Fotios;Timciuc, Vladlen;Wilken, Rachel;Ford, William T;Damgov, Jordan;Chao, Yuan;Beri, Suman Bala;Cankocak, Kerem;Van Remortel, Nick;Rodozov, Mircho;Halkiadakis, Eva;Navarria, Francesco;Girgis, Semiray;Bellan, Riccardo;Kim, Gui Nyun;Sanders, Stephen;Chang, Sunghyun;Brochet, Sébastien;De La Cruz, Begona;Goldstein, Joel;Naumann-Emme, Sebastian;George, Christopher;Wolszczak, Weronika;Vavilov, Sergey;Dugad, Shashikant;Snow, Gregory R;Gilbert, Andrew
Contributors:	理學院物理學系
Keywords:	Experiment;High Energy Physics - Experiment;Particle Physics;Physics
Date:	2015-01-01
Issue Date:	2026-04-23 12:15:31 (UTC+8)
Publisher:	Elsevier
Abstract:	摘要： A measurement of the production cross section ratio $\sigma(\chi_{b2}(1\mathrm{P}))/ \sigma(\chi_{b1}(1\mathrm{P}))$ is presented. The $\chi_{b1}(1\mathrm{P})$ and $\chi_{b2}(1\mathrm{P})$ bottomonium states, promptly produced in pp collisions at $\sqrt{s}$= 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays $\chi_{b1,2}(1\mathrm{P}) \rightarrow \Upsilon(1\mathrm{S}) + \gamma$. The emitted photons are measured through their conversion to e$^+$e$^-$ pairs, whose reconstruction allows the two states to be resolved. The $\Upsilon(1\mathrm{S})$ is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb$^{-1}$ is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, \|$\eta^\gamma$\| < 1.0; the $\Upsilon(1\mathrm{S})$ rapidity, \|$y^\Upsilon$\| < 1.5; and the $\Upsilon(1\mathrm{S})$ transverse momentum, 7 < $p_{\mathrm{T}}^\Upsilon$ < 40 GeV. The cross section ratio shows no significant dependence on the $\Upsilon(1\mathrm{S})$ transverse momentum, with a measured average value of $0.85 \pm 0.07\,\text{(stat+syst)}\pm 0.08\,\text{(BF)}$, where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the $\chi_{b}$ branching fractions. A measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P)) is presented. The χb1(1P) and χb2(1P) bottomonium states, promptly produced in pp collisions at s=8 TeV , are detected by the CMS experiment at the CERN LHC through their radiative decays χb1,2(1P)→ϒ(1S)+γ . The emitted photons are measured through their conversion to e+e− pairs, whose reconstruction allows the two states to be resolved. The ϒ(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb−1 is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, \|ηγ\|<1.0 ; the ϒ(1S) rapidity, \|yϒ\|<1.5 ; and the ϒ(1S) transverse momentum, 7<pTϒ<40 GeV . The cross section ratio shows no significant dependence on the ϒ(1S) transverse momentum, with a measured average value of 0.85±0.07(stat+syst)±0.08(BF) , where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the χb branching fractions. A measurement of the production cross section ratio sigma(chi[b2](1P)) / sigma( chi[b1](1P)) is presented. The chi[b1](1P) and chi[b2](1P) bottomonium states, promptly produced in pp collisions at sqrt(s) = 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays chi[b1,2](1P) to Upsilon(1S) + gamma. The emitted photons are measured through their conversion to electron-positron pairs, whose reconstruction allows the two states to be resolved. The Upsilon(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 inverse femtobarns is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, abs(eta[gamma]) < 1.0; the Upsilon(1S) rapidity, abs(y[Upsilon]) < 1.5; and the Upsilon(1S) transverse momentum, 7 < pt[Upsilon] < 40 GeV. The cross section ratio shows no significant dependence on the Upsilon(1S) transverse momentum, with a measured average value of 0.85 +/- 0.07 (stat+syst) +/- 0.08 (BF), where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the chi[b] branching fractions. 出版者： Elsevier 出版日期： 2015 出處： Physics letters. B, 2015, Vol.743, p.383-402 資源來源： Elsevier ScienceDirect Journals Complete 版權： CC0 1.0 - Universal 識別號： ISSN: 0370-2693 識別號： EISSN: 1873-2445 識別號： DOI: 10.1016/j.physletb.2015.02.048
Appears in Collections:	[Department of Physics] journal & Dissertation

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