Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021122
Javier Montaño-Domínguez, Fernando I. Ramírez-Zavaleta, Eduardo S. Tututi, Everardo Urquiza-Trejo
We present our results on the top quark chromomagnetic dipole moment, which is based on the 5-dimension effective Lagrangian operator that characterizes the chromodipolar vertex functions gtt and ggtt. The chromomagnetic dipole mu_t is derived via quantum fluctuation at the 1-loop level. We evaluate µˆt(s) as a function of the energy scale s=+-E2, for E=[10,1000] GeV. In particular we focus on the conventional high-energy scale E=mZ, analogously as with alphas(mZ2) and sW(mZ2). The spacelike evaluation matches quite well with the experimental central value, while the timelike case deviates from it.
{"title":"The top quark chromomagnetic dipole moment in the SM","authors":"Javier Montaño-Domínguez, Fernando I. Ramírez-Zavaleta, Eduardo S. Tututi, Everardo Urquiza-Trejo","doi":"10.31349/suplrevmexfis.4.021122","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021122","url":null,"abstract":"We present our results on the top quark chromomagnetic dipole moment, which is based on the 5-dimension effective Lagrangian operator that characterizes the chromodipolar vertex functions gtt and ggtt. The chromomagnetic dipole mu_t is derived via quantum fluctuation at the 1-loop level. We evaluate µˆt(s) as a function of the energy scale s=+-E2, for E=[10,1000] GeV. In particular we focus on the conventional high-energy scale E=mZ, analogously as with alphas(mZ2) and sW(mZ2). The spacelike evaluation matches quite well with the experimental central value, while the timelike case deviates from it.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135207812","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021116
Erik Alfredo Zepeda García, A. Ortiz
Over the last years, Machine Learning (ML) methods have been successfully applied to a wealth of problems in high-energy physics. In this work, we discuss the extraction of the average number of Multiparton Interactions (⟨Nmpi⟩) from minimum-bias pp data at LHC energies using a regression based on Boosted Decision Trees (BDT). Using the available ALICE data on transverse momentum spectra as a function of multiplicity, we report that for minimum-bias pp collisions at √s = 7 TeV the average Nmpi is 3.98 ± 1.01, which complements our previous results for pp collisions at √s = 5.02 and 13 TeV. The comparisons indicated a modest center-of-mass energy dependence of ⟨Nmpi⟩. The study is further extended extracting the multiplicity dependence of Nmpi for the three center-of-mass energies. These results are qualitatively consistent with the existing ALICE measurements sensitives to Multiparton Interactions (MPI). Through the ML method applied to pp collisions at √s = 13 TeV, we also show that computing the multiplicity in the forward region the extraction of Nmpi is improved. This result opens the possibility to extract the number of MPI event-by-event, and in this way study the particle production as a function of MPI. Our results provide additional evidence of the presence of MPI in hadronic interactions and can help to the understanding of the heavy-ion-like behaviour observed in pp collisions data.
{"title":"Extraction of multiparton interactions from ALICE pp collisions data using machine learning","authors":"Erik Alfredo Zepeda García, A. Ortiz","doi":"10.31349/suplrevmexfis.4.021116","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021116","url":null,"abstract":"Over the last years, Machine Learning (ML) methods have been successfully applied to a wealth of problems in high-energy physics. In this work, we discuss the extraction of the average number of Multiparton Interactions (⟨Nmpi⟩) from minimum-bias pp data at LHC energies using a regression based on Boosted Decision Trees (BDT). Using the available ALICE data on transverse momentum spectra as a function of multiplicity, we report that for minimum-bias pp collisions at √s = 7 TeV the average Nmpi is 3.98 ± 1.01, which complements our previous results for pp collisions at √s = 5.02 and 13 TeV. The comparisons indicated a modest center-of-mass energy dependence of ⟨Nmpi⟩. The study is further extended extracting the multiplicity dependence of Nmpi for the three center-of-mass energies. These results are qualitatively consistent with the existing ALICE measurements sensitives to Multiparton Interactions (MPI). Through the ML method applied to pp collisions at √s = 13 TeV, we also show that computing the multiplicity in the forward region the extraction of Nmpi is improved. This result opens the possibility to extract the number of MPI event-by-event, and in this way study the particle production as a function of MPI. Our results provide additional evidence of the presence of MPI in hadronic interactions and can help to the understanding of the heavy-ion-like behaviour observed in pp collisions data.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202737","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021105
Juan Marquez
We use the most general four-lepton effective interaction Hamiltonian to investigate the impact of massive Dirac and Majorana neutrinos on the leptonic decays of muons and taus. Our analysis encompasses the specific energy and angular distribution of the resulting charged lepton, accounting for both the initial and final polarizations of the charged leptons. Additionally, we identify the emergence of novel generalized Michel parameters and concentrate on the influence of the heavy neutrino masses, which can make significant contributions in cases where new sterile neutrinos exhibit non-negligible mixing. Our analysis reveals that the most promising scenario occurs in the case of τ decays, featuring one heavy neutrino with a mass approximately ranging from 10^2 to 10^3 MeV. In this setting, the discrepancy between the Dirac and Majorana cases could reach an order of magnitude of 10^−4, which is significant enough to be detected in present and future experiments.
{"title":"Michel parameters for elucidating the neutrinos nature and searching for new physics","authors":"Juan Marquez","doi":"10.31349/suplrevmexfis.4.021105","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021105","url":null,"abstract":"
 
 
 We use the most general four-lepton effective interaction Hamiltonian to investigate the impact of massive Dirac and Majorana neutrinos on the leptonic decays of muons and taus. Our analysis encompasses the specific energy and angular distribution of the resulting charged lepton, accounting for both the initial and final polarizations of the charged leptons. Additionally, we identify the emergence of novel generalized Michel parameters and concentrate on the influence of the heavy neutrino masses, which can make significant contributions in cases where new sterile neutrinos exhibit non-negligible mixing. Our analysis reveals that the most promising scenario occurs in the case of τ decays, featuring one heavy neutrino with a mass approximately ranging from 10^2 to 10^3 MeV. In this setting, the discrepancy between the Dirac and Majorana cases could reach an order of magnitude of 10^−4, which is significant enough to be detected in present and future experiments.
 
 
","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202738","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 estimate the squared speed of sound for the hot and dense QCD states formed in ion collisions at very high energies by exploring the implications of small-bounded and geometry effects in the String Percolation Model. The squared sound velocity shows signals of a local minimum (knee point) below the critical temperature consistent with the softest point in the equation of state and the onset of quark deconfinement that characterizes the quark-gluon plasma phase transition.
{"title":"Speed of sound of a non-equilibrium medium formed at LHC energies","authors":"Jesús Ricardo Alvarado García, Irais Bautista, Arturo Fernández Téllez","doi":"10.31349/suplrevmexfis.4.021112","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021112","url":null,"abstract":"We estimate the squared speed of sound for the hot and dense QCD states formed in ion collisions at very high energies by exploring the implications of small-bounded and geometry effects in the String Percolation Model. The squared sound velocity shows signals of a local minimum (knee point) below the critical temperature consistent with the softest point in the equation of state and the onset of quark deconfinement that characterizes the quark-gluon plasma phase transition.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202739","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021110
Martin Hentschinski
We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering of electrons and proton in the region of low Bjorken x. Using their proposed relation between parton number and entanglement entropy, we determine the latter using both conventional parton distribution functions and parton distribution functions obtained from an unintegrated gluon distribution subject to next-to-leading order Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution as well as from a dipole cross-section, subject to running coupling Balitsky-Kovchegov (rcBK) evolution. We compare our results to hadronic entropy obtained from final state hadron multiplicity.
{"title":"Entangelement entropy in high energy collisions of electrons and protons","authors":"Martin Hentschinski","doi":"10.31349/suplrevmexfis.4.021110","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021110","url":null,"abstract":"We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering of electrons and proton in the region of low Bjorken x. Using their proposed relation between parton number and entanglement entropy, we determine the latter using both conventional parton distribution functions and parton distribution functions obtained from an unintegrated gluon distribution subject to next-to-leading order Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution as well as from a dipole cross-section, subject to running coupling Balitsky-Kovchegov (rcBK) evolution. We compare our results to hadronic entropy obtained from final state hadron multiplicity.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135203061","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021117
Fabiola Fortuna
Standard model-dark matter particles, mediated by spin one fields, are analyzed within the effective field theory framework. We [1, 2] consider dark particles masses from few MeV to 6.4 TeV. We restrict the EFT using bounds from relic density, Z invisible decay width, direct and indirect detection limits and collider constraints. Solutions below mZ are found for two operators. Others, around the electroweak scale or slightly above, are also compatible with all present limits.
{"title":"DM-SM interactions mediated by spin-one particles: EFT study","authors":"Fabiola Fortuna","doi":"10.31349/suplrevmexfis.4.021117","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021117","url":null,"abstract":"Standard model-dark matter particles, mediated by spin one fields, are analyzed within the effective field theory framework. We [1, 2] consider dark particles masses from few MeV to 6.4 TeV. We restrict the EFT using bounds from relic density, Z invisible decay width, direct and indirect detection limits and collider constraints. Solutions below mZ are found for two operators. Others, around the electroweak scale or slightly above, are also compatible with all present limits.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206393","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021111
Fabiola Fortuna
In this work we analyze cLFV processes using a low-energy EFT that induces the effective interaction between two charged leptons of different flavor and two photons. We compute ℓi → ℓjγ, ℓi → ℓjγγ decays and ℓi → ℓj conversion in nuclei. We derived indirect upper limits on the double photon decays, which turned out to be below current experimental bounds. Our prediction for ℓ → τ conversion in nuclei is below the expected sensitivity of the NA64 experiment
{"title":"Study of cLFV with ℓiℓjγγ effective vertex","authors":"Fabiola Fortuna","doi":"10.31349/suplrevmexfis.4.021111","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021111","url":null,"abstract":"In this work we analyze cLFV processes using a low-energy EFT that induces the effective interaction between two charged leptons of different flavor and two photons. We compute ℓi → ℓjγ, ℓi → ℓjγγ decays and ℓi → ℓj conversion in nuclei. We derived indirect upper limits on the double photon decays, which turned out to be below current experimental bounds. Our prediction for ℓ → τ conversion in nuclei is below the expected sensitivity of the NA64 experiment","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206874","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021103
German Fabricio Roberto Sborlini
The calculation of higher-order corrections in Quantum Field Theories is a challenging task. In particular, dealing with multiloop and multileg Feynman amplitudes leads to severe bottlenecks and a very fast scaling of the computational resources required to perform the calculation. With the purpose of overcoming these limitations, we discuss efficient strategies based on the Loop-Tree Duality, its manifestly causal representation and the underlying geometrical interpretation. In concrete, we exploit the geometrical causal selection rules to define a Hamiltonian whose ground-state is directly related to the terms contributing to the causal representation. In this way, the problem can be translated into a minimization one and implemented in a quantum computer to search for a potential speed-up.
{"title":"Geometrical causality: casting Feynman integrals into quantum algorithms","authors":"German Fabricio Roberto Sborlini","doi":"10.31349/suplrevmexfis.4.021103","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021103","url":null,"abstract":"The calculation of higher-order corrections in Quantum Field Theories is a challenging task. In particular, dealing with multiloop and multileg Feynman amplitudes leads to severe bottlenecks and a very fast scaling of the computational resources required to perform the calculation. With the purpose of overcoming these limitations, we discuss efficient strategies based on the Loop-Tree Duality, its manifestly causal representation and the underlying geometrical interpretation. In concrete, we exploit the geometrical causal selection rules to define a Hamiltonian whose ground-state is directly related to the terms contributing to the causal representation. In this way, the problem can be translated into a minimization one and implemented in a quantum computer to search for a potential speed-up.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202740","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021115
Jesús Alejandro Miranda Hernández
We revisit the isospin-breaking and electromagnetic corrections of some hadronic tau decays, which can also be employed to extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus. We extend former analyses by Antonelli et al. working with ChPT with resonances. We find that going beyond the Low approximation, these corrections play an important role between the π− K0 and K− π0 modes. The K− K0 channel is also discussed.
{"title":"Electromagnetic corrections in hadronic tau decays","authors":"Jesús Alejandro Miranda Hernández","doi":"10.31349/suplrevmexfis.4.021115","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021115","url":null,"abstract":"We revisit the isospin-breaking and electromagnetic corrections of some hadronic tau decays, which can also be employed to extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus. We extend former analyses by Antonelli et al. working with ChPT with resonances. We find that going beyond the Low approximation, these corrections play an important role between the π− K0 and K− π0 modes. The K− K0 channel is also discussed.","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202900","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}
Pub Date : 2023-09-18DOI: 10.31349/suplrevmexfis.4.021106
A. Marin
The ALICE experiment is devoted to the study of the quark-gluon plasma (QGP) created in heavy-ion collisions at the CERN LHC. The experimental setup allows for the study of many different observables that contributed to the characterization of the properties of the QGP. The ALICE experiment went through a major upgrade during LS2 to profit from the increased LHC luminosity and to improve the tracking resolution. An additional upgrade is planned for LS3. A new experiment, ALICE 3, was proposed as next major upgrade in LS4. In this contribution, a selection of recent physics results was presented together with a glimpse of the next upgrades during LS3 and LS4, with the main focus on ALICE 3 and its physics program
{"title":"Latest results of the ALICE Collaboration and plans for ALICE 3","authors":"A. Marin","doi":"10.31349/suplrevmexfis.4.021106","DOIUrl":"https://doi.org/10.31349/suplrevmexfis.4.021106","url":null,"abstract":"The ALICE experiment is devoted to the study of the quark-gluon plasma (QGP) created in heavy-ion collisions at the CERN LHC. The experimental setup allows for the study of many different observables that contributed to the characterization of the properties of the QGP. The ALICE experiment went through a major upgrade during LS2 to profit from the increased LHC luminosity and to improve the tracking resolution. An additional upgrade is planned for LS3. A new experiment, ALICE 3, was proposed as next major upgrade in LS4. In this contribution, a selection of recent physics results was presented together with a glimpse of the next upgrades during LS3 and LS4, with the main focus on ALICE 3 and its physics program","PeriodicalId":210091,"journal":{"name":"Suplemento de la Revista Mexicana de Física","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206375","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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