We study the application of BCFW recursion relations to the QED process 0→e^(-)e^(+)nγ.Based on 6-point amplitudes(both MHVA and NMHVA)computed from Feynman diagrams in the Berends-Giele gauge,we conduct a comprehen...We study the application of BCFW recursion relations to the QED process 0→e^(-)e^(+)nγ.Based on 6-point amplitudes(both MHVA and NMHVA)computed from Feynman diagrams in the Berends-Giele gauge,we conduct a comprehensive study on different shifts.Subsequently,we propose a new shift(LLYZ shift),which can lead to the full amplitudes of these processes and have several realistic computational advantages.We compare the number of terms and independent amplitudes of this novel shift with those of a few typical shifts.展开更多
We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of ...We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of the clq scalar meson fo scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-Ds hard-wall models are the favorite candidates of the realistic holographic QCD model.展开更多
Feynman loop integrals are a key ingredient for the calculation of higher order radiation effects, and are responsible for reliable and accurate theoretical prediction. We improve the efficiency of numerical integrati...Feynman loop integrals are a key ingredient for the calculation of higher order radiation effects, and are responsible for reliable and accurate theoretical prediction. We improve the efficiency of numerical integration in sector decomposition by implementing a quasi-Monte Carlo method associated with the CUDA/GPU technique. For demonstration we present the results of several Feynman integrals up to two loops in both Euclidean and physical kinematic regions in comparison with those obtained from FIESTA3. It is shown that both planar and non-planar two-loop master integrals in the physical kinematic region can be evaluated in less than half a minute with O（10^（-3））accuracy, which makes the direct numerical approach viable for precise investigation of higher order effects in multiloop processes, e.g. the next-to-leading order QCD effect in Higgs pair production via gluon fusion with a finite top quark mass.展开更多
We explore the possibility that the dark matter relic density is not produced by a thermal mechanism directly,but by the decay of other heavier dark-sector particles which themselves can be produced by the thermal fre...We explore the possibility that the dark matter relic density is not produced by a thermal mechanism directly,but by the decay of other heavier dark-sector particles which themselves can be produced by the thermal freeze-out mechanism.Using a concrete model with light dark matter from dark sector decay,we study the collider signature of the dark sector particles associated with Higgs production processes.We find that future lepton colliders could be a better place to probe the signature of this kind of light dark matter model than hadron colliders such as LHC.Also,we find that a Higgs factory with center-of-mass energy 250 GeV has a better potential to resolve the signature of this kind of light dark matter model than a Higgs factory with center-of-mass energy 350 GeV.展开更多
We explore the discovery potential of Higgs pair production at a 100 Te V collider via full leptonic mode.The same mode can be explored at the LHC when Higgs pair production is enhanced by new physics. We examine two ...We explore the discovery potential of Higgs pair production at a 100 Te V collider via full leptonic mode.The same mode can be explored at the LHC when Higgs pair production is enhanced by new physics. We examine two types of fully leptonic final states and propose a partial reconstruction method, which can reconstruct some useful kinematic observables. It is found that the m T2 variable determined by this reconstruction method and the reconstructed visible Higgs mass are crucial to discriminate the signal and background events. It is also noticed that a new variable, denoted as △m, which is defined as the mass difference of two possible combinations, is very useful as a discriminant. To examine the detector effects, we consider seven detector setups for a 100 Te V collider and investigate the changes in the sensitivity, and we find that lepton isolation and the minimal lepton P t cut are crucial in order to reduce the integrated luminosity.展开更多
We derive cubic and quartic couplings of the Higgs singlet extension of the SM and the two Higgs doublet model. We also examine the number of CP violated couplings in a model with n Higgs doublet model and a model wit...We derive cubic and quartic couplings of the Higgs singlet extension of the SM and the two Higgs doublet model. We also examine the number of CP violated couplings in a model with n Higgs doublet model and a model with ns Higgs singlets and ndHiggs doublets. We conclude that in order to reconstruct the Higgs potential with multi Higgs fields at the LHC and future colliders, to detect the cubic/quartic couplings is necessary.展开更多
基金Supported by the Natural Science Foundation of China (11475180, 11875260)Supported by the Italian Ministry of Research (MUR)(PRIN20172LNEEZ)
文摘We study the application of BCFW recursion relations to the QED process 0→e^(-)e^(+)nγ.Based on 6-point amplitudes(both MHVA and NMHVA)computed from Feynman diagrams in the Berends-Giele gauge,we conduct a comprehensive study on different shifts.Subsequently,we propose a new shift(LLYZ shift),which can lead to the full amplitudes of these processes and have several realistic computational advantages.We compare the number of terms and independent amplitudes of this novel shift with those of a few typical shifts.
基金Supported by CAS Program 'Outstanding Young Scientists Abroad Brought-in', CAS Key Project (KJCX3-SYW-N2), NSFC(10875134, 10735040)supported by National Science Council (NCS) of Taiwan (97-2112-M-009-019-MY3)National Center for Theoretical Sciences(NCTS) through NCS of Taiwan
文摘We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of the clq scalar meson fo scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-Ds hard-wall models are the favorite candidates of the realistic holographic QCD model.
基金Supported by the Natural Science Foundation of China(11305179 11475180)Youth Innovation Promotion Association,CAS,IHEP Innovation(Y4545170Y2)+1 种基金State Key Lab for Electronics and Particle Detectors,Open Project Program of State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,China(Y4KF061CJ1)Cluster of Excellence Precision Physics,Fundamental Interactions and Structure of Matter(PRISMA-EXC 1098)
文摘Feynman loop integrals are a key ingredient for the calculation of higher order radiation effects, and are responsible for reliable and accurate theoretical prediction. We improve the efficiency of numerical integration in sector decomposition by implementing a quasi-Monte Carlo method associated with the CUDA/GPU technique. For demonstration we present the results of several Feynman integrals up to two loops in both Euclidean and physical kinematic regions in comparison with those obtained from FIESTA3. It is shown that both planar and non-planar two-loop master integrals in the physical kinematic region can be evaluated in less than half a minute with O（10^（-3））accuracy, which makes the direct numerical approach viable for precise investigation of higher order effects in multiloop processes, e.g. the next-to-leading order QCD effect in Higgs pair production via gluon fusion with a finite top quark mass.
基金Supported by National Natural Science Foundation of China(11875130).Supported by the National Natural Science Foundation of China(11475180,11875260)。
文摘We explore the possibility that the dark matter relic density is not produced by a thermal mechanism directly,but by the decay of other heavier dark-sector particles which themselves can be produced by the thermal freeze-out mechanism.Using a concrete model with light dark matter from dark sector decay,we study the collider signature of the dark sector particles associated with Higgs production processes.We find that future lepton colliders could be a better place to probe the signature of this kind of light dark matter model than hadron colliders such as LHC.Also,we find that a Higgs factory with center-of-mass energy 250 GeV has a better potential to resolve the signature of this kind of light dark matter model than a Higgs factory with center-of-mass energy 350 GeV.
基金Supported by Natural Science Foundation of China(11175251,11305179,11675185,11475180,11575005)The work of Q.Li and Q.S.Yan is partially supported by CAS Center for Excellence in Particle Physics(CCEPP)X.Zhao is partially supported by the European Union as part of the FP7 Marie Curie Initial Training Network MCnet ITN(PITN-GA-2012-315877)
文摘We explore the discovery potential of Higgs pair production at a 100 Te V collider via full leptonic mode.The same mode can be explored at the LHC when Higgs pair production is enhanced by new physics. We examine two types of fully leptonic final states and propose a partial reconstruction method, which can reconstruct some useful kinematic observables. It is found that the m T2 variable determined by this reconstruction method and the reconstructed visible Higgs mass are crucial to discriminate the signal and background events. It is also noticed that a new variable, denoted as △m, which is defined as the mass difference of two possible combinations, is very useful as a discriminant. To examine the detector effects, we consider seven detector setups for a 100 Te V collider and investigate the changes in the sensitivity, and we find that lepton isolation and the minimal lepton P t cut are crucial in order to reduce the integrated luminosity.
基金Supported by the Natural Science Foundation of China under Grant Nos.11175251 and 11575005
文摘We derive cubic and quartic couplings of the Higgs singlet extension of the SM and the two Higgs doublet model. We also examine the number of CP violated couplings in a model with n Higgs doublet model and a model with ns Higgs singlets and ndHiggs doublets. We conclude that in order to reconstruct the Higgs potential with multi Higgs fields at the LHC and future colliders, to detect the cubic/quartic couplings is necessary.
