Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the l...Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.展开更多
Using the form factors from light-cone sum rules, we study the branching ratios and forward-backward asymmetries （FBAs） of the exclusive decays Bu^＋→π^＋e^＋e^- and Bu^＋ →ρ^＋e^＋e^- （e= e,μ） in the standar...Using the form factors from light-cone sum rules, we study the branching ratios and forward-backward asymmetries （FBAs） of the exclusive decays Bu^＋→π^＋e^＋e^- and Bu^＋ →ρ^＋e^＋e^- （e= e,μ） in the standard model （SM） and the top quark two-Higgs-doublet model （T2HDM）. From the numerical results, we find that the new physics contributions cannot provide very large enhancement to the branching ratios and the theoretical predictions are in good agreement with the SM ones. The T2HDM effects on FBAs of these decays are small. Precision measurements of the dilepton invariant mass distributions, especially in the lower dilepton mass region, and the FBAs in the decays Bu^＋ → π^＋ （ρ^＋ ）e^＋ e^- will greatly help in discriminating among the SM and the new physics models.展开更多
We calculate the new physics contributions to the neutral Bd^o and Ba^o meson mass splitting △Md and △Ma induced by the box diagrams involving the charged-Higgs bosons in the top quark two-Higgs doublet model （T2HD...We calculate the new physics contributions to the neutral Bd^o and Ba^o meson mass splitting △Md and △Ma induced by the box diagrams involving the charged-Higgs bosons in the top quark two-Higgs doublet model （T2HDM）. Using the precision data, we obtain the bounds on the parameter space of the T2HDM： （a） For fixed MH = 400 GeV and 5= [0°, 60°], the upper bound on tan β is tan β≤ 30 after the inclusion of major theoretical uncertainties; （b） For the case of tan β≤ 20, a light charged Higgs boson with a mass around 300 GeV is allowed; and （c） The bounds on tan β and MH are strongly correlated： a smaller （larger） tan β means a lighter （heavier） charged Higgs boson.展开更多
A quark star, black hole pairing as a would-be Gravitational wave generator is brought up. Quark stars are, anyway, likely to be black holes, above a certain mass limit, whereas a quark star in itself obey thermodynam...A quark star, black hole pairing as a would-be Gravitational wave generator is brought up. Quark stars are, anyway, likely to be black holes, above a certain mass limit, whereas a quark star in itself obey thermodynamic “laws” which in certain ways differ from the traditional black hole models. We list some of the probable consequences of such a binary, and make predictions as to certain GW phenomenon which will have observational consequences. <i>i.e.</i>, a GW “change in energy” from a black hole—Quark star pair would likely be within 90% of that of comparatively massed black hole—black hole binary pair. The electromagnetic “profile” of the two cases would differ dramatically, and we conclude our inquiry with an open question if a generalized uncertainty principle could play a role in comparing the 7<sup>th</sup> and 8<sup>th</sup> equations of our presentation.展开更多
Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damp...Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damping on the scalar-induced gravitational waves(SIGWs).Resulting from the dissipation of cosmic fluid,the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of weakly-interacting particles.The effect offers a novel observable for probing the underlying particle interaction,especially for those mediated by heavy gauge bosons beyond the standard model of particles.We anticipate that pulsar timing arrays are sensitive to gauge bosons with mass∼10^(3)-10^(4)GeV,while space-and ground-based interferometers to those with mass∼10^(7)-10^(12)GeV,leading to essential comple-ments to on-going and future experiments of high-energy physics.展开更多
Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of...Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet.We show that the pure gauge operators generate both ZγZ^*and Zγγ^*vertices with rapid energy dependence∝E^5,which can be probed sensitively via the reaction e^+e^-→Zγ.We demonstrate that measuring the nTGCs via the reaction e^+e^-→Zγfollowed by Z→qq decays can probe the new physics scales of dimension-8 pure gauge operators up to the range(1-5)TeV at the CEPC,FCC-ee and ILC colliders with s~(1/2)=(0.25-1)TeV,and up to the range(10-16)TeV at CLIC with s~(1/2)=(3-5)TeV,assuming in each case an integrated luminosity of 5 ab~(-1).We compare these sensitivities with the corresponding probes of the dimension-8 nTGC operators involving Higgs doublets and the dimension-8 fermionic contact operators that contribute to the e^+e^-Zγvertex.展开更多
We explore constraints on various new physics resonances from four top-quark production based on current experimental data.Both light and heavy resonances are studied in this work.A comparison of the full width effect...We explore constraints on various new physics resonances from four top-quark production based on current experimental data.Both light and heavy resonances are studied in this work.A comparison of the full width effect and narrow width approximation is also presented.展开更多
We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small p...We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small penguin contribution in B → J/ψπ0 decay can be calculated with this method.We suggest two methods to extract the weak phase β.One is through the dependence of the mixing induced CP asymmetry SJ/ψπ0 on the weak phase β,the other is from the relation of the total asymmetry ACP with the weak phase β.Our results show that the deviation ΔSJ/ψπ0 of the mixing induced CP asymmetry from sin（-2β） is of O（10-3） and has much less uncertainty.The above O（10-3） deviation can provide a good reference for identifying new physics.展开更多
A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e^＋e^-→γh could...A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e^＋e^-→γh could be a useful channel for new physics. We express new physics model-independently in the effective Lagrangian approach,and find that the new physics effects of γh have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculate for the first time the 95% confidence level（CL） bounds of γh at the Higgs factory, and prove that γh is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run.展开更多
We show that the signature of two boosted W-jets plus substantial missing energy is very promising for probing heavy charged resonances(X^(±))through the process of pp→X^(+)X^(-)→W^(+)W^(-)X^(0) X^(0),where X^(...We show that the signature of two boosted W-jets plus substantial missing energy is very promising for probing heavy charged resonances(X^(±))through the process of pp→X^(+)X^(-)→W^(+)W^(-)X^(0) X^(0),where X^(0) denotes the dark matter candidate.The hadronic decay mode of the W boson is considered to maximize the number of signal events.When the mass split between X±and X0 is large,the jet-substructure technique must be utilized to analyze the boosted W-jet.Here,we consider the process of chargino pair production at the LHC,i.e.,pp→χ^(+)_(1)χ^(-)_(1)→W^(+)W^(-)χ^(0)_(1)χ^(0)_(1),and demonstrate that the proposed signature is able to cover more parameter space of m_(χ1)^(±)and m_(χ1)0,than the conventional signature of multiple leptons plus missing energy.More importantly,the signature of interest is not sensitive to the spin of heavy resonances.展开更多
Anomalies in decays induced by b→ct Ve(l=e,μ,T)transitions may imply lepton flavor universality violations,which raises questions on such phenomena in the D decays induced by c→(s,d)t+ve transitions.Current measure...Anomalies in decays induced by b→ct Ve(l=e,μ,T)transitions may imply lepton flavor universality violations,which raises questions on such phenomena in the D decays induced by c→(s,d)t+ve transitions.Current measurements of the pure leptonic and semi-leptonic D decays agree with the standard model(SM)predictions,and such agreements can be used to constrain the new physics(NP)contributions.In this work,we extend SM by as-suming general efective Hamiltonians describing the c→(s,d)t+Ve transitions including the full set of the four-fermion operators.With the latest experimental data,we perform a least χ^(2) fit of the Wilson cofficient corresponding to each operator.The results indicate that the Wilson coefficients of tensor and scalar operators in the muon sector are in the order of 0(10^(-2))while others are in the order of 0(10^(-3)).The lepton flavor universality could be violated by interactions with the scalar operators.We also determine that the pure leptonic decays are significantly sensitive to scalar operators.The efects of NP on the semi-leptonic decays with electron final state are negligible;however,for the decays with the muon final state,the effects of scalar and tensor operators will appear in the forward-back-ward asymmetries and the muon helicity asymmetries of D→Pμ^(+)Vpμdecays.The future measurements of these de-cays in the BESIII and Belle II experiments will facilitate the evaluation of NP effects.展开更多
Using the ionic liquid[emim][Tf2N]as a physical solvent,it was found by Aspen Plus simulation that it was possible to attempt to capture CO2 from the flue gas discharged from the coal-fired unit of the power plant.Usi...Using the ionic liquid[emim][Tf2N]as a physical solvent,it was found by Aspen Plus simulation that it was possible to attempt to capture CO2 from the flue gas discharged from the coal-fired unit of the power plant.Using the combination of model calculation and experimental determination,the density,isostatic heat capacity,viscosity,vapor pressure,thermal conductivity,surface tension and solubility of[emim][Tf2N]were obtained.Based on the NRTL model,the Henry coefficient and NRTL binary interaction parameters of CO2 dissolved in[emim][Tf2N]were obtained by correlating[emim][Tf2N]with the gas–liquid equilibrium data of CO2.Firstly,the calculated relevant data is imported into Aspen Plus,and the whole process model of the ionic liquid absorption process is established.Then the absorption process is optimized according to the temperature distribution in the absorption tower to obtain a new absorption process.Finally,the density,constant pressure heat capacity,surface tension,thermal conductivity,and viscosity of[emim][Tf2N]were changed to investigate the effect of ionic liquid properties on process energy consumption,solvent circulation and heat exchanger design.The results showed that based on the composition of the inlet gas stream to the absorbers,CO2 with a capture rate of 90%and a mass purity higher than 99.5%was captured.These results indicate that the[emim][Tf2N]could be used as a physical solvent for CO2 capture from coal-fired units.In addition,the results will provide a theoretical basis for the design of new ionic liquids for CO2 capture.展开更多
The principal assumptions about equivalence and energy distribution of the asdorption sites on solidsurfaces used by Langmuir for deriving the equation of monomolecular adsorption are generalized and anew physical ads...The principal assumptions about equivalence and energy distribution of the asdorption sites on solidsurfaces used by Langmuir for deriving the equation of monomolecular adsorption are generalized and anew physical adsorption model is proposed and tested with experimental data published in literature.Themodels of Langmuir,Freundlich,Temkin etc.are only the special cases.Assuming uniform density distributionof adsorption energy,the isotherm equation is given asn=K.1n[1+（bop）1/Mor n=K.1n[1+（boC）1/M]where n is the amount of adsorption per unit weight or area of solid p or C is tbe pressure of gas or the concen-tration of solution respectively.K,bo,M are constants with physical meanings as described in this paper.This equation can be used over wide range to quantitatively represent the five types of physical adsorptionclassified by Brunauer.展开更多
Collider is a machine or device that usually causes two beams of high-speed particles moving to collide in a straight line. The fundamental purpose of a collision is to obtain an abnormal mass-energy density and attem...Collider is a machine or device that usually causes two beams of high-speed particles moving to collide in a straight line. The fundamental purpose of a collision is to obtain an abnormal mass-energy density and attempt to discover new physics and new substances namely new physical states. However, linear collisions are not easy to achieve the above purpose. Through the comparable experiment of rear-end collision, head-on collision and orthogonal collision of two low-velocity particles, this paper theoretically proposes a new idea that the orthogonal collision between two-beam high-velocity particles can really produce an abnormal mass-energy density. This machine based on the new idea of orthogonal collision can not only greatly reduce the construction cost of colliders, but also is the most effective way to achieve the purpose of collision.展开更多
As an approximate Goldstone boson with zero quantum number and zero standard model charge,the long-lived η meson exhibits the decay processes that offer a unique opportunity to explore physics beyond the standard mod...As an approximate Goldstone boson with zero quantum number and zero standard model charge,the long-lived η meson exhibits the decay processes that offer a unique opportunity to explore physics beyond the standard model and new sources of charge parity violation.Further,they facilitate the testing of the low-energy quantum chromodynamics theory and measurement of the fundamental parameters of light quarks.To pursue these goals,we propose a plan to construct a super ηfactory at HIAF high-energy terminal or at CiADS after its energy upgrade.The high-intensity proton beam at HIAF enables the production of many η samples,exceeding 1013events per year during the first stage,utilizing multiple layers of thin targets composed of light nuclei.This paper presents the physics goals,the first-version conceptual design of the spectrometer,and preliminary simulation results.展开更多
Introducing the top partner is a common way to cancel the largest quadratically divergent contribution to the Higgs mass induced by the top quark. In this work, we study single top partner production in the tZ channel...Introducing the top partner is a common way to cancel the largest quadratically divergent contribution to the Higgs mass induced by the top quark. In this work, we study single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity(LHT). Since it is well known that polarized beams can enhance the cross section, we analyze the signal via polarized electron beams,and photon beams. we have selected two decay modes for comparison, based on the leptonic or the hadronic decays of the W and Z from the top partner. We then construct a detailed detector simulation, and choose a set of cuts to enhance signal significance. For mode A(B), the capacity for exclusion in this process at s1/2=3TeV is comparable to the current experimental limits with L=1000(500) fb-1. If the integrated luminosity can be increased to 3000 fb-1, the top partner mass+mTcan be excluded up to 1350(1440) GeV at 2σ level. We also considered the initial state radiation effect, and find that this effect reduces the excluding ability of the eγ collision on the the top partner mass by approximately 10 GeV. Moreover, the ability to exclude the LHT parameter space at eγ collision complements the existing research.展开更多
Rare decay processes K→πvv^-and KL→π^0vv^-are considered in the framework of three-site Higgsless model.The contributions of this new physics model to these two decay processes come from the new heavy gauge bosons...Rare decay processes K→πvv^-and KL→π^0vv^-are considered in the framework of three-site Higgsless model.The contributions of this new physics model to these two decay processes come from the new heavy gauge bosons and the correction terms for the couplings of the ordinary gauge bosons with fermions.Our numerical results show that the branching ratios of these two decay processes can be enhanced by 40%and 50%relative to those predicted by the standard model.展开更多
We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle,facilitating exclusive interactions between dark matter and the top quark in the Standard Model.The analysis f...We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle,facilitating exclusive interactions between dark matter and the top quark in the Standard Model.The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model.Notably,in instances when dark matter mass is small,the tree-level two-body annihilation process experiences suppression.In such scenarios,the contributions of the threebody process(χχ→tbW-)and the one-loop process(χχ→gg)dominate the relic abundance.With regard to direct detection,calculations were performed for the two-loop contribution to the dark-matter-gluon interaction,yielding the corresponding spin-independent scattering cross section.展开更多
The SO（3） gauge extension of SM, which is proposed to present a successful explanation for the observed small masses of neutrino and the nearly tri-bimaximal neutrino mixing, predicted the vector-like SO（3） triple...The SO（3） gauge extension of SM, which is proposed to present a successful explanation for the observed small masses of neutrino and the nearly tri-bimaximal neutrino mixing, predicted the vector-like SO（3） triplet Majorana neutrinos and SUL（2） double Higgs bosons. In this work we calculate branching ratios of the charged lepton flavor violating decays lIlJV （V = γ, Z） induced by these Majorana neutrinos and Higgs bosons. We find that under the model parameters constrained by experimental bounds on the decays Z →lIlJ, the branching ratio of decays lI→lJγ can be up to 10^-10, which may be accessible at the future experiments.展开更多
文摘Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.
基金National Natural Science Foundation of China under Grant No.10575052the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) under Grant No.20050319008the Special Study Foundation of Nanyang Normal University under Grant No.nynu200750
文摘Using the form factors from light-cone sum rules, we study the branching ratios and forward-backward asymmetries （FBAs） of the exclusive decays Bu^＋→π^＋e^＋e^- and Bu^＋ →ρ^＋e^＋e^- （e= e,μ） in the standard model （SM） and the top quark two-Higgs-doublet model （T2HDM）. From the numerical results, we find that the new physics contributions cannot provide very large enhancement to the branching ratios and the theoretical predictions are in good agreement with the SM ones. The T2HDM effects on FBAs of these decays are small. Precision measurements of the dilepton invariant mass distributions, especially in the lower dilepton mass region, and the FBAs in the decays Bu^＋ → π^＋ （ρ^＋ ）e^＋ e^- will greatly help in discriminating among the SM and the new physics models.
基金The project partly supported by National Natural Science Foundation of China under Grant No. 10575052 and the Specialized Research Fund for the Doctoral Program of Higher Education （SRFDP） under Grant No. 20050319008.Acknowledgments 0ne of the authors Lin-Xia Lü would like to thank Prof. C.S. Huang for his valuable help.
文摘We calculate the new physics contributions to the neutral Bd^o and Ba^o meson mass splitting △Md and △Ma induced by the box diagrams involving the charged-Higgs bosons in the top quark two-Higgs doublet model （T2HDM）. Using the precision data, we obtain the bounds on the parameter space of the T2HDM： （a） For fixed MH = 400 GeV and 5= [0°, 60°], the upper bound on tan β is tan β≤ 30 after the inclusion of major theoretical uncertainties; （b） For the case of tan β≤ 20, a light charged Higgs boson with a mass around 300 GeV is allowed; and （c） The bounds on tan β and MH are strongly correlated： a smaller （larger） tan β means a lighter （heavier） charged Higgs boson.
文摘A quark star, black hole pairing as a would-be Gravitational wave generator is brought up. Quark stars are, anyway, likely to be black holes, above a certain mass limit, whereas a quark star in itself obey thermodynamic “laws” which in certain ways differ from the traditional black hole models. We list some of the probable consequences of such a binary, and make predictions as to certain GW phenomenon which will have observational consequences. <i>i.e.</i>, a GW “change in energy” from a black hole—Quark star pair would likely be within 90% of that of comparatively massed black hole—black hole binary pair. The electromagnetic “profile” of the two cases would differ dramatically, and we conclude our inquiry with an open question if a generalized uncertainty principle could play a role in comparing the 7<sup>th</sup> and 8<sup>th</sup> equations of our presentation.
基金supported by the National Natural Science Foundation of China(Grant No.12175243)the National Key R&D Program of China(Grant No.2023YFC2206403)+1 种基金the Science Research Grants from the China Manned Space Project(Grant No.CMS-CSST-2021-B01)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB15)。
文摘Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damping on the scalar-induced gravitational waves(SIGWs).Resulting from the dissipation of cosmic fluid,the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of weakly-interacting particles.The effect offers a novel observable for probing the underlying particle interaction,especially for those mediated by heavy gauge bosons beyond the standard model of particles.We anticipate that pulsar timing arrays are sensitive to gauge bosons with mass∼10^(3)-10^(4)GeV,while space-and ground-based interferometers to those with mass∼10^(7)-10^(12)GeV,leading to essential comple-ments to on-going and future experiments of high-energy physics.
基金supported by PAPIIT(DGAPA-UNAM) project IN106913 and CONACyT(Mexico) project 151234support by the Mainz Institute for Theoretical Physics(MITP) where part of this work was completed.A.F.is supported in part by the National Science Foundation under grant no. PHY-1212635
文摘Revised November 2013 by J. Erler （U. Mexico） and A. Freit＆s （Pittsburgh U.）.10.1 Introduction 10.2 Renormalization and radiative corrections
基金supported in part by United Kingdom STFC(Grant No.ST/P000258/1)in part by the Estonian Research Council via a Mobilitas Pluss grant+5 种基金in part by the TDLI distinguished visiting fellow programmesupported in part by the National Natural Science Foundation of China(Grant Nos.11675086,and 11835005)supported in part by the CAS Center for Excellence in Particle Physics(CCEPP)the National Key R&D Program of China(Grant No.2017YFA0402204)the Key Laboratory for Particle Physics,Astrophysics and Cosmology(Ministry of Education)the Office of Science and Technology,Shanghai Municipal Government(Grant No.16DZ2260200)。
文摘Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet.We show that the pure gauge operators generate both ZγZ^*and Zγγ^*vertices with rapid energy dependence∝E^5,which can be probed sensitively via the reaction e^+e^-→Zγ.We demonstrate that measuring the nTGCs via the reaction e^+e^-→Zγfollowed by Z→qq decays can probe the new physics scales of dimension-8 pure gauge operators up to the range(1-5)TeV at the CEPC,FCC-ee and ILC colliders with s~(1/2)=(0.25-1)TeV,and up to the range(10-16)TeV at CLIC with s~(1/2)=(3-5)TeV,assuming in each case an integrated luminosity of 5 ab~(-1).We compare these sensitivities with the corresponding probes of the dimension-8 nTGC operators involving Higgs doublets and the dimension-8 fermionic contact operators that contribute to the e^+e^-Zγvertex.
基金Supported in part by the National Science Foundation of China(11725520,11675002,11635001,11805013,12075257)the Fundamental Research Funds for the Central Universities(2018NTST09)+1 种基金the funding from the Institute of High Energy Physics,Chinese Academy of Sciences(Y6515580U1)the funding from Chinese Academy of Sciences(Y8291120K2)。
文摘We explore constraints on various new physics resonances from four top-quark production based on current experimental data.Both light and heavy resonances are studied in this work.A comparison of the full width effect and narrow width approximation is also presented.
文摘We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small penguin contribution in B → J/ψπ0 decay can be calculated with this method.We suggest two methods to extract the weak phase β.One is through the dependence of the mixing induced CP asymmetry SJ/ψπ0 on the weak phase β,the other is from the relation of the total asymmetry ACP with the weak phase β.Our results show that the deviation ΔSJ/ψπ0 of the mixing induced CP asymmetry from sin（-2β） is of O（10-3） and has much less uncertainty.The above O（10-3） deviation can provide a good reference for identifying new physics.
基金Supported by National Natural Science Foundation of China(11275102)Tsinghua Scholarship for Overseas Graduate Studies
文摘A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e^＋e^-→γh could be a useful channel for new physics. We express new physics model-independently in the effective Lagrangian approach,and find that the new physics effects of γh have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculate for the first time the 95% confidence level（CL） bounds of γh at the Higgs factory, and prove that γh is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run.
基金Supported in part by the National Science Foundation of China(11725520,11675002,11635001,11805013,12075257)the Fundamental Research Funds for the Central Universities(2018NTST09)。
文摘We show that the signature of two boosted W-jets plus substantial missing energy is very promising for probing heavy charged resonances(X^(±))through the process of pp→X^(+)X^(-)→W^(+)W^(-)X^(0) X^(0),where X^(0) denotes the dark matter candidate.The hadronic decay mode of the W boson is considered to maximize the number of signal events.When the mass split between X±and X0 is large,the jet-substructure technique must be utilized to analyze the boosted W-jet.Here,we consider the process of chargino pair production at the LHC,i.e.,pp→χ^(+)_(1)χ^(-)_(1)→W^(+)W^(-)χ^(0)_(1)χ^(0)_(1),and demonstrate that the proposed signature is able to cover more parameter space of m_(χ1)^(±)and m_(χ1)0,than the conventional signature of multiple leptons plus missing energy.More importantly,the signature of interest is not sensitive to the spin of heavy resonances.
基金Supported in part by the National Natural Science Foundation of China(11975195,11705159)the Natural Science Foundation of Shandong province(ZR2019JQ004,ZR2018JL001)the Project of Shandong Province Higher Educational Science and Technology Program(2019KJJ007)。
文摘Anomalies in decays induced by b→ct Ve(l=e,μ,T)transitions may imply lepton flavor universality violations,which raises questions on such phenomena in the D decays induced by c→(s,d)t+ve transitions.Current measurements of the pure leptonic and semi-leptonic D decays agree with the standard model(SM)predictions,and such agreements can be used to constrain the new physics(NP)contributions.In this work,we extend SM by as-suming general efective Hamiltonians describing the c→(s,d)t+Ve transitions including the full set of the four-fermion operators.With the latest experimental data,we perform a least χ^(2) fit of the Wilson cofficient corresponding to each operator.The results indicate that the Wilson coefficients of tensor and scalar operators in the muon sector are in the order of 0(10^(-2))while others are in the order of 0(10^(-3)).The lepton flavor universality could be violated by interactions with the scalar operators.We also determine that the pure leptonic decays are significantly sensitive to scalar operators.The efects of NP on the semi-leptonic decays with electron final state are negligible;however,for the decays with the muon final state,the effects of scalar and tensor operators will appear in the forward-back-ward asymmetries and the muon helicity asymmetries of D→Pμ^(+)Vpμdecays.The future measurements of these de-cays in the BESIII and Belle II experiments will facilitate the evaluation of NP effects.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China(LY16B060014)State Key Laboratory of Chemical Engineering(No.SKL-ChE-08A01)the Innovation and Development of Marine Economy Demonstration。
文摘Using the ionic liquid[emim][Tf2N]as a physical solvent,it was found by Aspen Plus simulation that it was possible to attempt to capture CO2 from the flue gas discharged from the coal-fired unit of the power plant.Using the combination of model calculation and experimental determination,the density,isostatic heat capacity,viscosity,vapor pressure,thermal conductivity,surface tension and solubility of[emim][Tf2N]were obtained.Based on the NRTL model,the Henry coefficient and NRTL binary interaction parameters of CO2 dissolved in[emim][Tf2N]were obtained by correlating[emim][Tf2N]with the gas–liquid equilibrium data of CO2.Firstly,the calculated relevant data is imported into Aspen Plus,and the whole process model of the ionic liquid absorption process is established.Then the absorption process is optimized according to the temperature distribution in the absorption tower to obtain a new absorption process.Finally,the density,constant pressure heat capacity,surface tension,thermal conductivity,and viscosity of[emim][Tf2N]were changed to investigate the effect of ionic liquid properties on process energy consumption,solvent circulation and heat exchanger design.The results showed that based on the composition of the inlet gas stream to the absorbers,CO2 with a capture rate of 90%and a mass purity higher than 99.5%was captured.These results indicate that the[emim][Tf2N]could be used as a physical solvent for CO2 capture from coal-fired units.In addition,the results will provide a theoretical basis for the design of new ionic liquids for CO2 capture.
文摘The principal assumptions about equivalence and energy distribution of the asdorption sites on solidsurfaces used by Langmuir for deriving the equation of monomolecular adsorption are generalized and anew physical adsorption model is proposed and tested with experimental data published in literature.Themodels of Langmuir,Freundlich,Temkin etc.are only the special cases.Assuming uniform density distributionof adsorption energy,the isotherm equation is given asn=K.1n[1+（bop）1/Mor n=K.1n[1+（boC）1/M]where n is the amount of adsorption per unit weight or area of solid p or C is tbe pressure of gas or the concen-tration of solution respectively.K,bo,M are constants with physical meanings as described in this paper.This equation can be used over wide range to quantitatively represent the five types of physical adsorptionclassified by Brunauer.
文摘Collider is a machine or device that usually causes two beams of high-speed particles moving to collide in a straight line. The fundamental purpose of a collision is to obtain an abnormal mass-energy density and attempt to discover new physics and new substances namely new physical states. However, linear collisions are not easy to achieve the above purpose. Through the comparable experiment of rear-end collision, head-on collision and orthogonal collision of two low-velocity particles, this paper theoretically proposes a new idea that the orthogonal collision between two-beam high-velocity particles can really produce an abnormal mass-energy density. This machine based on the new idea of orthogonal collision can not only greatly reduce the construction cost of colliders, but also is the most effective way to achieve the purpose of collision.
基金supported by the National Natural Science Foundation of China(Nos.12222512 and 12005266)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34030300).
文摘As an approximate Goldstone boson with zero quantum number and zero standard model charge,the long-lived η meson exhibits the decay processes that offer a unique opportunity to explore physics beyond the standard model and new sources of charge parity violation.Further,they facilitate the testing of the low-energy quantum chromodynamics theory and measurement of the fundamental parameters of light quarks.To pursue these goals,we propose a plan to construct a super ηfactory at HIAF high-energy terminal or at CiADS after its energy upgrade.The high-intensity proton beam at HIAF enables the production of many η samples,exceeding 1013events per year during the first stage,utilizing multiple layers of thin targets composed of light nuclei.This paper presents the physics goals,the first-version conceptual design of the spectrometer,and preliminary simulation results.
基金supported by the National Natural Science Foundation of China(NNSFC)under grant No.11405047。
文摘Introducing the top partner is a common way to cancel the largest quadratically divergent contribution to the Higgs mass induced by the top quark. In this work, we study single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity(LHT). Since it is well known that polarized beams can enhance the cross section, we analyze the signal via polarized electron beams,and photon beams. we have selected two decay modes for comparison, based on the leptonic or the hadronic decays of the W and Z from the top partner. We then construct a detailed detector simulation, and choose a set of cuts to enhance signal significance. For mode A(B), the capacity for exclusion in this process at s1/2=3TeV is comparable to the current experimental limits with L=1000(500) fb-1. If the integrated luminosity can be increased to 3000 fb-1, the top partner mass+mTcan be excluded up to 1350(1440) GeV at 2σ level. We also considered the initial state radiation effect, and find that this effect reduces the excluding ability of the eγ collision on the the top partner mass by approximately 10 GeV. Moreover, the ability to exclude the LHT parameter space at eγ collision complements the existing research.
基金supported in part by the National Natural Science Foundation of China under Grant No.10675057Foundation of Liaoning Education Committee under Grant No.2007T086
文摘Rare decay processes K→πvv^-and KL→π^0vv^-are considered in the framework of three-site Higgsless model.The contributions of this new physics model to these two decay processes come from the new heavy gauge bosons and the correction terms for the couplings of the ordinary gauge bosons with fermions.Our numerical results show that the branching ratios of these two decay processes can be enhanced by 40%and 50%relative to those predicted by the standard model.
基金supported in part by the National Science Foundation of China under Grant Nos. 12222502 and 12075257。
文摘We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle,facilitating exclusive interactions between dark matter and the top quark in the Standard Model.The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model.Notably,in instances when dark matter mass is small,the tree-level two-body annihilation process experiences suppression.In such scenarios,the contributions of the threebody process(χχ→tbW-)and the one-loop process(χχ→gg)dominate the relic abundance.With regard to direct detection,calculations were performed for the two-loop contribution to the dark-matter-gluon interaction,yielding the corresponding spin-independent scattering cross section.
文摘The SO（3） gauge extension of SM, which is proposed to present a successful explanation for the observed small masses of neutrino and the nearly tri-bimaximal neutrino mixing, predicted the vector-like SO（3） triplet Majorana neutrinos and SUL（2） double Higgs bosons. In this work we calculate branching ratios of the charged lepton flavor violating decays lIlJV （V = γ, Z） induced by these Majorana neutrinos and Higgs bosons. We find that under the model parameters constrained by experimental bounds on the decays Z →lIlJ, the branching ratio of decays lI→lJγ can be up to 10^-10, which may be accessible at the future experiments.
