The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
We describe predictions for top quark pair differential distributions at hadron colliders,by combining the next-to-next-to-leading order quantum chromodynamics calculations and next-to-leading order electroweak correc...We describe predictions for top quark pair differential distributions at hadron colliders,by combining the next-to-next-to-leading order quantum chromodynamics calculations and next-to-leading order electroweak corrections with double resummation at the next-to-next-to-leading logarithmic accuracy of threshold logarithms and small-mass logarithms.To the best of our knowledge,this is the first study to present such a combination,which incorporates all known perturbative information.Numerical results are presented for the invariant-mass distribution,transverse-momentum distribution,and rapidity distributions.展开更多
In this paper, we present the universal structure of the alphabet of one-loop Feynman integrals. The letters in the alphabet are calculated using the Baikov representation with cuts. We consider both convergent and di...In this paper, we present the universal structure of the alphabet of one-loop Feynman integrals. The letters in the alphabet are calculated using the Baikov representation with cuts. We consider both convergent and divergent cut integrals and observe that letters in the divergent cases can be easily obtained from convergent cases by applying certain limits. The letters are written as simple expressions in terms of various Gram determinants. The knowledge of the alphabet enables us to easily construct the canonical differential equations of the d log form and aids in bootstrapping the symbols of the solutions.展开更多
In this study,we investigate the invariant-mass distribution of top-quark pairs near the 2mt threshold,which strongly influences the determination of the top-quark mass mt.Higher-order non-relativistic corrections lea...In this study,we investigate the invariant-mass distribution of top-quark pairs near the 2mt threshold,which strongly influences the determination of the top-quark mass mt.Higher-order non-relativistic corrections lead to large contributions,which are not included in the state-of-the-art theoretical predictions.A factorization formula is derived to resum such corrections to all orders in the strong-coupling,and necessary ingredients are calculated to perform the resummation at next-to-leading power.We combine the resummation with fixed-order results and present phenomenologically relevant numerical results.The resummation effect significantly increases the differential cross-section in the threshold region and makes the theoretical prediction more compatible with experimental data.We estimate that using our prediction in the determination of mt will lead to a value closer to the direct measurement result.展开更多
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
文摘We describe predictions for top quark pair differential distributions at hadron colliders,by combining the next-to-next-to-leading order quantum chromodynamics calculations and next-to-leading order electroweak corrections with double resummation at the next-to-next-to-leading logarithmic accuracy of threshold logarithms and small-mass logarithms.To the best of our knowledge,this is the first study to present such a combination,which incorporates all known perturbative information.Numerical results are presented for the invariant-mass distribution,transverse-momentum distribution,and rapidity distributions.
基金the National Natural Science Foundation of China(11975030,11635001,11925506)。
文摘In this paper, we present the universal structure of the alphabet of one-loop Feynman integrals. The letters in the alphabet are calculated using the Baikov representation with cuts. We consider both convergent and divergent cut integrals and observe that letters in the divergent cases can be easily obtained from convergent cases by applying certain limits. The letters are written as simple expressions in terms of various Gram determinants. The knowledge of the alphabet enables us to easily construct the canonical differential equations of the d log form and aids in bootstrapping the symbols of the solutions.
基金Supported in part by the National Natural Science Foundation of China(11975030,11635001,11575004)W.-L.Ju was Supported in part by the China Postdoctoral Science Foundation(2017M610685)。
文摘In this study,we investigate the invariant-mass distribution of top-quark pairs near the 2mt threshold,which strongly influences the determination of the top-quark mass mt.Higher-order non-relativistic corrections lead to large contributions,which are not included in the state-of-the-art theoretical predictions.A factorization formula is derived to resum such corrections to all orders in the strong-coupling,and necessary ingredients are calculated to perform the resummation at next-to-leading power.We combine the resummation with fixed-order results and present phenomenologically relevant numerical results.The resummation effect significantly increases the differential cross-section in the threshold region and makes the theoretical prediction more compatible with experimental data.We estimate that using our prediction in the determination of mt will lead to a value closer to the direct measurement result.
