In 2015 and 2018 the COMPASS experiment at CERN measured muon-pair production in the Drell-Yan (DY) and J/Psi channels using a 190 GeV π− beam impinging on a transversely polarized NH3 and unpolarized nuclear targets (27Al, 184W). Apart from the absolute cross-section measurements for both processes, COMPASS studies also the target spin (in)dependent azimuthal asymmetries in both channels. Assuming the valence quark-antiquark annihilation to be the main production mechanism, one can interpret the azimuthal asymmetries in terms of convolutions of pion and proton Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs). The TMD PDFs are universal QCD objects providing a mapping of parton densities in 3D momentum space. Recent results obtained by COMPASS for the DY and J/ψ channels will be discussed along with complementary semi-inclusive DIS (SIDIS) measurements and theoretical predictions.
在2015年和2018年，欧洲核子研究中心的COMPASS实验使用190 GeV π−光束撞击横向极化的NH3和非极化的核目标(27Al, 184W)，测量了dll - yan (DY)和J/Psi通道中的介子对产生。除了两个过程的绝对横截面测量外，COMPASS还研究了两个通道中目标自旋(in)相关的方位角不对称性。假设价夸克-反夸克湮灭是主要的产生机制，人们可以根据介子和质子的横向动量依赖(TMD)部子分布函数(pdf)的卷积来解释方位角不对称。TMD pdf是通用的QCD对象，提供了三维动量空间中部分密度的映射。COMPASS最近获得的DY和J/ψ通道的结果将与互补的半包容DIS (SIDIS)测量和理论预测一起讨论。
{"title":"Drell-Yan measurements at the COMPASS experiment","authors":"M. Meyer-Conde","doi":"10.22323/1.390.0488","DOIUrl":"https://doi.org/10.22323/1.390.0488","url":null,"abstract":"In 2015 and 2018 the COMPASS experiment at CERN measured muon-pair production in the Drell-Yan (DY) and J/Psi channels using a 190 GeV π− beam impinging on a transversely polarized NH3 and unpolarized nuclear targets (27Al, 184W). Apart from the absolute cross-section measurements for both processes, COMPASS studies also the target spin (in)dependent azimuthal asymmetries in both channels. Assuming the valence quark-antiquark annihilation to be the main production mechanism, one can interpret the azimuthal asymmetries in terms of convolutions of pion and proton Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs). The TMD PDFs are universal QCD objects providing a mapping of parton densities in 3D momentum space. Recent results obtained by COMPASS for the DY and J/ψ channels will be discussed along with complementary semi-inclusive DIS (SIDIS) measurements and theoretical predictions.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82049544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this proceeding, I will address the possibility that the nature of dark matter is associated with neutrinomass generation. Focusing on an extension of the StandardModelwhere the light neutrino masses are generated radiatively, we study the properties of a dark matter candidate which is made stable by the same symmetry responsible for the radiative origin of neutrino masses. Also, the model studied proposes a dark matter candidate that could be both a neutral scalar or a fermion. I will discuss the phenomenology of both scenarios, studying the parameter space which allows to reproduce the observed dark matter abundance. I will also comment on the expected signals in direct detection experiments, via indirect detection probes and at colliders.
{"title":"An extensive study of dark matter and neutrino phenomenology in the Triplet + Singlet Scotogenic Model","authors":"Ivania Maturana","doi":"10.22323/1.390.0263","DOIUrl":"https://doi.org/10.22323/1.390.0263","url":null,"abstract":"In this proceeding, I will address the possibility that the nature of dark matter is associated with neutrinomass generation. Focusing on an extension of the StandardModelwhere the light neutrino masses are generated radiatively, we study the properties of a dark matter candidate which is made stable by the same symmetry responsible for the radiative origin of neutrino masses. Also, the model studied proposes a dark matter candidate that could be both a neutral scalar or a fermion. I will discuss the phenomenology of both scenarios, studying the parameter space which allows to reproduce the observed dark matter abundance. I will also comment on the expected signals in direct detection experiments, via indirect detection probes and at colliders.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78487286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The hypertriton is a bound state of a proton, a neutron and a Λ baryon. Studying its internal structure is crucial to investigate the hyperon–nucleon strong interaction and offers insights into the inner core of neutron stars, where Λ production is favoured. One powerful way to investigate the hypertriton’s internal structure is to measure precisely its lifetime. The hypertriton is an extremely loosely bound object with a lambda separation energy EΛ of only 130 keV. Therefore the hypertriton lifetime is expected to be close to the one of the free Λ. Thanks to the very large set of Pb–Pb collision data collected during LHC Run 2, the ALICE collaboration has performed systematic studies on the hypertriton lifetime. The hypertriton 2-body mesonic decay channel has been studied with the help of machine learning techniques for the signal extraction. The precision of the new ALICE results on the hypertriton lifetime is comparable with the current world average and the measured lifetime value confirms the weakly-bound nature of the hypertriton.
超子是质子、中子和Λ重子的束缚态。研究其内部结构对于研究超子-核子强相互作用至关重要，并提供了对中子星内核的见解，其中Λ的产生是有利的。研究超海旋子内部结构的一个有效方法是精确测量它的寿命。超旋子是一种束缚极其松散的物体，其分离能EΛ仅为130 keV。因此，超氚寿命预计将接近于自由的Λ。得益于LHC Run 2期间收集的大量Pb-Pb碰撞数据，ALICE合作项目对超重子寿命进行了系统的研究。利用机器学习技术研究了超子二体中介子衰变通道的信号提取。新的ALICE结果的精度与目前的世界平均水平相当，测量的寿命值证实了超海旋子的弱束缚性质。
{"title":"Investigating the hyperon-nucleon strong interaction with a precision measurement of the hypertriton lifetime in ALICE","authors":"F. Mazzaschi","doi":"10.22323/1.390.0486","DOIUrl":"https://doi.org/10.22323/1.390.0486","url":null,"abstract":"The hypertriton is a bound state of a proton, a neutron and a Λ baryon. Studying its internal structure is crucial to investigate the hyperon–nucleon strong interaction and offers insights into the inner core of neutron stars, where Λ production is favoured. One powerful way to investigate the hypertriton’s internal structure is to measure precisely its lifetime. The hypertriton is an extremely loosely bound object with a lambda separation energy EΛ of only 130 keV. Therefore the hypertriton lifetime is expected to be close to the one of the free Λ. Thanks to the very large set of Pb–Pb collision data collected during LHC Run 2, the ALICE collaboration has performed systematic studies on the hypertriton lifetime. The hypertriton 2-body mesonic decay channel has been studied with the help of machine learning techniques for the signal extraction. The precision of the new ALICE results on the hypertriton lifetime is comparable with the current world average and the measured lifetime value confirms the weakly-bound nature of the hypertriton.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80611650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New observation of Charmonium decays at BESIII","authors":"Weimin Song","doi":"10.22323/1.390.0503","DOIUrl":"https://doi.org/10.22323/1.390.0503","url":null,"abstract":"","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89285613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Drell-Yan Measurements with the CMS experiment","authors":"I. Gorbunov","doi":"10.22323/1.390.0461","DOIUrl":"https://doi.org/10.22323/1.390.0461","url":null,"abstract":"","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82701202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prativa Pritimita, Chayan Majumdar, Sudhanwa Patra, S. Senapati, U. Yajnik
We consider a gauged U(1)Lμ−Lτ extension of the left-right symmetric theory in order to simultaneously explain neutrino mass, mixing and muon anomalous magnetic moment. We get sizeable contribution from the interaction of the new light gauge boson Zμτ of U(1)Lμ−Lτ symmetry with muons which can individually satisfy the current bounds on muon (g − 2) anomaly . The other positive contributions to ∆aμ come from the interactions of neutral CP-even scalars with muons and that of singly charged gauge boson WL with heavy neutrinos which is facilitated by inverse seesaw mechanism that explains neutrino mass in our model. The results show that the model gives a small but non-negligible contribution to ∆aμ thereby eliminating the entire deviation in theoretical prediction and experimental result of muon (g − 2) anomaly.
{"title":"Muon (g-2) anomaly in extended left-right symmetric model","authors":"Prativa Pritimita, Chayan Majumdar, Sudhanwa Patra, S. Senapati, U. Yajnik","doi":"10.22323/1.390.0308","DOIUrl":"https://doi.org/10.22323/1.390.0308","url":null,"abstract":"We consider a gauged U(1)Lμ−Lτ extension of the left-right symmetric theory in order to simultaneously explain neutrino mass, mixing and muon anomalous magnetic moment. We get sizeable contribution from the interaction of the new light gauge boson Zμτ of U(1)Lμ−Lτ symmetry with muons which can individually satisfy the current bounds on muon (g − 2) anomaly . The other positive contributions to ∆aμ come from the interactions of neutral CP-even scalars with muons and that of singly charged gauge boson WL with heavy neutrinos which is facilitated by inverse seesaw mechanism that explains neutrino mass in our model. The results show that the model gives a small but non-negligible contribution to ∆aμ thereby eliminating the entire deviation in theoretical prediction and experimental result of muon (g − 2) anomaly.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82337318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Zdráhal,a,∗ Karol Kampf, Marc Knecht and Jiří Novotný Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, CZ-180 00 Prague 8, Czech Republic Centre de Physique Théorique, CNRS/Aix-Marseille Univ./Univ. du Sud Toulon-Var (UMR 7332) CNRS-Luminy Case 907, 13288 Marseille Cedex 9, France E-mail: zdrahal@ipnp.mff.cuni.cz, kampf@ipnp.mff.cuni.cz,
{"title":"On dispersive representation of kaon and eta decays to 3 pions","authors":"M. Zdráhal, K. Kampf, M. Knecht, J. Novotný","doi":"10.22323/1.390.0523","DOIUrl":"https://doi.org/10.22323/1.390.0523","url":null,"abstract":"Martin Zdráhal,a,∗ Karol Kampf, Marc Knecht and Jiří Novotný Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, CZ-180 00 Prague 8, Czech Republic Centre de Physique Théorique, CNRS/Aix-Marseille Univ./Univ. du Sud Toulon-Var (UMR 7332) CNRS-Luminy Case 907, 13288 Marseille Cedex 9, France E-mail: zdrahal@ipnp.mff.cuni.cz, kampf@ipnp.mff.cuni.cz,","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"605 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77613662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the effect of CP violation in the Higgs sector of the U(1)′-extended MSSM. We are particularly interested in the mass and decay dependence of the second lightest neutral Higgs boson, in the presence of CP violating phases for μe f f . The masses of the neutral Higgs bosons are calculated at the one-loop level by taking into account the contributions from top and bottom (s)quark sectors. We study the production and decay channels of the second lightest neutral Higgs boson for a set of benchmark points consistent with the current experimental constraints. We then implement the model into standard packages and perform a detailed and systematic analysis of production and decay modes at the HE-LHC with 27 TeV.
{"title":"The Next Higgs Bosons in $E_{6}$ Inspired Supersymmetric Models with CP Violation","authors":"L. Selbuz","doi":"10.22323/1.390.0309","DOIUrl":"https://doi.org/10.22323/1.390.0309","url":null,"abstract":"We investigate the effect of CP violation in the Higgs sector of the U(1)′-extended MSSM. We are particularly interested in the mass and decay dependence of the second lightest neutral Higgs boson, in the presence of CP violating phases for μe f f . The masses of the neutral Higgs bosons are calculated at the one-loop level by taking into account the contributions from top and bottom (s)quark sectors. We study the production and decay channels of the second lightest neutral Higgs boson for a set of benchmark points consistent with the current experimental constraints. We then implement the model into standard packages and perform a detailed and systematic analysis of production and decay modes at the HE-LHC with 27 TeV.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75964952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Studies of the production of heavy-flavour baryons are of prominent importance to investigate hadronization mechanisms at the LHC, in particular through the study of the evolution of the baryon-over-meson production ratio. Measurements performed in pp and p--Pb collisions at the LHC have revealed unexpected features, qualitatively similar to what was observed in heavy-ion collisions and, in the charm sector, not in line with the expectations based on previous measurements from $rm e^+e^-$ colliders and in ep collisions. These results suggest that charmed baryon formation might not be universal and that the baryon-over-meson ratio depends on the collision system or multiplicity. A review of ALICE measurements of charmed baryons, including $rm Lambda_c^+/D^0$ as a function of charged-particle multiplicity in pp, p--Pb and Pb--Pb collisions, $rm Sigma_c^{0, +, ++}/D^0$ and $rm Xi_c^{0, +}/D^0$ as a function of $p_{rm T}$ in pp collisions and $rm Gamma(Xi_c^0rightarrowXi^-e^+nu_e)/Gamma(Xi_c^0rightarrowXi^-pi^+)$, will be presented. Comparison to phenomenological models will be also discussed. Emphasis will be given to the discussion of the impact of these studies on the understanding of hadronization processes.
{"title":"Hadronization studies at the LHC with ALICE","authors":"Jianhui Zhu","doi":"10.22323/1.390.0524","DOIUrl":"https://doi.org/10.22323/1.390.0524","url":null,"abstract":"Studies of the production of heavy-flavour baryons are of prominent importance to investigate hadronization mechanisms at the LHC, in particular through the study of the evolution of the baryon-over-meson production ratio. Measurements performed in pp and p--Pb collisions at the LHC have revealed unexpected features, qualitatively similar to what was observed in heavy-ion collisions and, in the charm sector, not in line with the expectations based on previous measurements from $rm e^+e^-$ colliders and in ep collisions. These results suggest that charmed baryon formation might not be universal and that the baryon-over-meson ratio depends on the collision system or multiplicity. A review of ALICE measurements of charmed baryons, including $rm Lambda_c^+/D^0$ as a function of charged-particle multiplicity in pp, p--Pb and Pb--Pb collisions, $rm Sigma_c^{0, +, ++}/D^0$ and $rm Xi_c^{0, +}/D^0$ as a function of $p_{rm T}$ in pp collisions and $rm Gamma(Xi_c^0rightarrowXi^-e^+nu_e)/Gamma(Xi_c^0rightarrowXi^-pi^+)$, will be presented. Comparison to phenomenological models will be also discussed. Emphasis will be given to the discussion of the impact of these studies on the understanding of hadronization processes.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80589479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Parkhomenko, A. Dobrynina, I. Karabanov, L. Vassilevskaya
The non-diagonal correlator of vector and tensor fermionic currents is considered as the concrete example of the two-point one-loop amplitudesmodified by a constant homogeneousmagnetic field. The crossed-field limit of this correlator is found. The tensor current is a fermionic part of the Pauli Lagrangian relevant for the electromagnetic interaction of fermions through the anomalous magnetic moment. Under assumption that this interaction enters the effective QED Lagrangian, the contribution to the photon polarization operator linear in AMM is calculated.
{"title":"Loop Amplitudes Induced by Tensor Fermionic Current in Constant Homogeneous Electromagnetic Fields","authors":"A. Parkhomenko, A. Dobrynina, I. Karabanov, L. Vassilevskaya","doi":"10.22323/1.390.0307","DOIUrl":"https://doi.org/10.22323/1.390.0307","url":null,"abstract":"The non-diagonal correlator of vector and tensor fermionic currents is considered as the concrete example of the two-point one-loop amplitudesmodified by a constant homogeneousmagnetic field. The crossed-field limit of this correlator is found. The tensor current is a fermionic part of the Pauli Lagrangian relevant for the electromagnetic interaction of fermions through the anomalous magnetic moment. Under assumption that this interaction enters the effective QED Lagrangian, the contribution to the photon polarization operator linear in AMM is calculated.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84214021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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