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Discrimination of converted photons and neutral pions at high energies
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作者 肖虹 陈国明 +14 位作者 陶军全 卞建国 范嘉伟 梁松 孟祥伟 沈玉乔 唐志成 王健 王健 汪先友 王征 徐明 许伟伟 杨民 严琪 《Chinese Physics C》 SCIE CAS CSCD 2012年第10期979-984,共6页
In the LHC experiment, the H →γγ channel provides a clean final state with an effective mass peak that is reconstructed with great precision, despite the small branching ratio. As a consequence, the H →γγ channe... In the LHC experiment, the H →γγ channel provides a clean final state with an effective mass peak that is reconstructed with great precision, despite the small branching ratio. As a consequence, the H →γγ channel is one of the most promising channels for the Higgs discovery in the very low mass region. In order to increase the sensitivity of the Higgs search, background rejection rate is very important, so γ/π 0 discrimination is one of the key points in the analysis. At least 40% of photons will convert with the experience of ATLAS and CMS. We constructed electromagnetic calorimeter (ECAL) in GEANT4 simulation, using 6 variables which have different shapes between converted γ and π 0 , with the TMVA (Toolkit for Multivariate Data Analysis) to do the separation. With this method we can get 30% to 60% π 0 rejection efficiency when keeping 90% converted γ efficiency, in the region of transverse momentum 15 GeV to 75 GeV, not only in MC sumulation but also in real data. 展开更多
关键词 converted γ π 0 DISCRIMINATION TMVA
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Study of diphoton decays of the lightest scalar Higgs boson in the Next-to-Minimal Supersymmetric Standard Model
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作者 范嘉伟 陶军全 +6 位作者 沈玉乔 陈国明 陈和生 S.Gascon-Shotkin M.Lethuillier L.Sgandurra P.Soulet 《Chinese Physics C》 SCIE CAS CSCD 2014年第7期1-8,共8页
The CMS and ATLAS experiments at the LHC have announced the discovery of a Higgs boson with mass at approximately 125 GeV/c2 in the search for the Standard Model Higgs boson via, notably, the 2/y and ZZ to four lepton... The CMS and ATLAS experiments at the LHC have announced the discovery of a Higgs boson with mass at approximately 125 GeV/c2 in the search for the Standard Model Higgs boson via, notably, the 2/y and ZZ to four leptons final states. Considering the recent results of the Higgs boson searches from the LHC, we study the lightest scalar Higgs boson hi in the Next-to-Minimal Supersymmetric Standard Model by restricting the next-to- lightest scalar Higgs boson h2 to be the observed to the 125 GeV/c2 state. We perform a scan over the relevant NMSSM parameter space that is favoured by low fine-tuning considerations. Moreover, we also take the experimental constraints from direct searches, B-physics observables, relic density, and anomalous magnetic moment of the muon measurements, as well as the theoretical considerations, into account in our specific scan. We find that the signal rate in the two-photon final state for the NMSSM Higgs boson hi with the mass range from about 80 GeV/e2 to about 122 CeV/c2 can be enhanced by a factor of up to 3.5 when the Higgs boson h2 is required to be compatible with the excess from latest LHC results. This motivates the extension of the search at the LHC for the Higgs boson hi in the diphoton final state down to masses of 80 GeV/c2, particularly with the upcoming proton-proton collision data to be taken at center-of-mass energies of 13-14 TeV. 展开更多
关键词 SUPERSYMMETRY Next-to-Minimal Supersymmetric Standard Model lightest scalar Higgs boson
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Production of γγ+2 jets from double parton scattering in proton-proton collisions at the LHC
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作者 陶军全 张思靓 +3 位作者 沈玉乔 范嘉伟 陈国明 陈和生 《Chinese Physics C》 SCIE CAS CSCD 2015年第12期1-6,共6页
Cross sections for the production of pairs of photons plus two additional jets produced from double parton scattering in high-energy proton-proton collisions at the LHC are calculated for the first time. The estimates... Cross sections for the production of pairs of photons plus two additional jets produced from double parton scattering in high-energy proton-proton collisions at the LHC are calculated for the first time. The estimates are based on the theoretical perturbative QCD predictions for the productions of γγ at next-to-next-to-leading-order, jet+jet and γ+jet at next-to-leading-order, for their corresponding single-scattering cross sections. The cross sections and expected event rates for γγ+2 jets from double parton scattering, after typical acceptance and selections, are given for proton-proton collisions with the collision energy s=13 TeV and integrated luminosity of 100 fb-1 planned for the following years, and also s=14 TeV with 3000 fb 1 of integrated luminosity as the LHC design. 展开更多
关键词 γγ+2 jets production double parton scattering QCD
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A method for the separation and reconstructions of charged hadron and neutral hadron from their overlapped showers in an electromagnetic calorimeter
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作者 梁松 陶军全 +17 位作者 沈玉乔 范嘉伟 肖虹 陈国明 陈和生 卞建国 陈晔 李祖豪 孟祥伟 唐志成 汪先友 王征 徐明 许伟伟 严琪 杨民 张诚 朱世海 《Chinese Physics C》 SCIE CAS CSCD 2013年第9期41-47,共7页
The separation and reconstructions of charged hadron and neutral hadron from their overlapped showers in an electromagnetic calorimeter is very important for the reconstructions of some particles with hadronic decays,... The separation and reconstructions of charged hadron and neutral hadron from their overlapped showers in an electromagnetic calorimeter is very important for the reconstructions of some particles with hadronic decays, for example the tau reconstruction in the searches for the Standard Model and supersymmetric Higgs bosons at the LHC. In this paper, a method combining the shower cluster in an electromagnetic calorimeter and the parametric formula for hadron showers, was developed to separate the overlapped showers between charged hadron and neutral hadron. Taking the hadronic decay containing one charged pion and one neutral pion in the final status of tau for example, satisfied results of the separation of the overlapped showers, the reconstructions of the energy and positions of the hadrons were obtained. An improved result for the tau reconstruction with this decay model can be also achieved after the application of the proposed method. 展开更多
关键词 separation and reconstructions overlapped showers parametric formula
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Search for a lighter Higgs boson in the Next-to-Minimal Supersymmetric Standard Model
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作者 Jun-Quan Tao M.Aamir Shahzad +7 位作者 Si-Jing Zhang Chu Wang Yu-Qiao Shen Guo-Ming Chen He-Sheng Chen S.Gascon-Shotkina L.Finco C.Camen 《Chinese Physics C》 SCIE CAS CSCD 2018年第10期51-58,共8页
Following the discovery of the Higgs boson with a mass of approximately 125 GeV at the LHC, many studies have been performed from both the theoretical and experimental viewpoints to search for a new Higgs Boson that i... Following the discovery of the Higgs boson with a mass of approximately 125 GeV at the LHC, many studies have been performed from both the theoretical and experimental viewpoints to search for a new Higgs Boson that is lighter than 125 GeV. We explore the possibility of constraining a lighter neutral scalar Higgs boson hi and a lighter pseudo-scalar Higgs boson al in the Next-to-Minimal Supersymmetric Standard Model by restricting the next-to-lightest scalar Higgs boson h2 to be the one observed at the LHC after applying the phenomenological constraints and those from experimental measurements. Such lighter particles are not yet completely excluded by the latest results of the search for a lighter Higgs boson in the diphoton decay channel from LHC data. Our results show that some new constraints on the Next-to-Minimal Supersymmetric Standard Model could be obtained for a lighter scalar Higgs boson at the LHC if such a search is performed by experimental collaborations and more data. The potentials of discovery for other interesting decay channels of such a lighter neutral scalar or pseudo-scalar particle are also discussed. 展开更多
关键词 Next-to-Minimal Supersymmetric Standard Model lighter Higgs boson discovery potentials
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