Pub Date : 2020-12-16DOI: 10.1103/PhysRevD.103.115020
P. Gutierrez, R. Jain, C. Kao
We investigate the prospects of discovering the top quark decay into a charm quark and a Higgs boson ($t to c h^0$) in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study flavor changing neutral Higgs (FCNH) interactions. We perform a parton level analysis as well as Monte Carlo simulations using textsc{Pythia}~8 and textsc{Delphes} to study the flavor changing top quark decay $t to c h^0$, followed by the Higgs decaying into $tau^+ tau^-$, with the other top quark decaying to a bottom quark ($b$) and two light jets ($tto bWto bjj$). To reduce the physics background to the Higgs signal, only the leptonic decays of tau leptons are used, $tau^+tau^- to e^pmmu^mp +slashed{E}_T$, where $slashed{E}_T$ represents the missing transverse energy from the neutrinos. In order to reconstruct the Higgs boson and top quark masses as well as to effectively remove the physics background, the collinear approximation for the highly boosted tau decays is employed. Our analysis suggests that a high energy LHC at $sqrt{s} = 27$ TeV will be able to discover this FCNH signal with an integrated luminosity $mathcal{L} = 3$ ab$^{-1}$ for a branching fraction ${cal B}(t to ch^0) agt 1.4 times 10^{-4}$ that corresponds to a FCNH coupling $|lambda_{tch}| agt 0.023$. This FCNH coupling is significantly below the current ATLAS combined upper limit of $|lambda_{tch}| = 0.064$.
我们研究了在欧洲核子研究中心大型强子对撞机(LHC)上发现顶夸克衰变为粲夸克和希格斯玻色子($t to c h^0$)的前景。采用一般的双希格斯双重态模型来研究变味中性希格斯相互作用。我们使用textsc{Pythia} 8和textsc{Delphes}进行了部子级分析和蒙特卡罗模拟，研究了口味变化的顶夸克衰变$t to c h^0$，随后希格斯衰变为$tau^+ tau^-$，另一个顶夸克衰变为一个底夸克($b$)和两个光射流($tto bWto bjj$)。为了减少希格斯信号的物理背景，只使用了tau轻子的轻子衰变，$tau^+tau^- to e^pmmu^mp +slashed{E}_T$，其中$slashed{E}_T$代表中微子丢失的横向能量。为了重建希格斯玻色子和顶夸克质量，并有效地去除物理背景，采用了高度增强的tau衰变的共线近似。我们的分析表明，$sqrt{s} = 27$ TeV的高能大型强子对撞机将能够发现具有积分光度$mathcal{L} = 3$ ab $^{-1}$的FCNH信号，其分支分数${cal B}(t to ch^0) agt 1.4 times 10^{-4}$对应于FCNH耦合$|lambda_{tch}| agt 0.023$。这种FCNH耦合明显低于当前ATLAS组合上限$|lambda_{tch}| = 0.064$。
{"title":"Flavor changing top decays to charm and a Higgs boson with \u0000ττ\u0000 at the LHC","authors":"P. Gutierrez, R. Jain, C. Kao","doi":"10.1103/PhysRevD.103.115020","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.115020","url":null,"abstract":"We investigate the prospects of discovering the top quark decay into a charm quark and a Higgs boson ($t to c h^0$) in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study flavor changing neutral Higgs (FCNH) interactions. We perform a parton level analysis as well as Monte Carlo simulations using textsc{Pythia}~8 and textsc{Delphes} to study the flavor changing top quark decay $t to c h^0$, followed by the Higgs decaying into $tau^+ tau^-$, with the other top quark decaying to a bottom quark ($b$) and two light jets ($tto bWto bjj$). To reduce the physics background to the Higgs signal, only the leptonic decays of tau leptons are used, $tau^+tau^- to e^pmmu^mp +slashed{E}_T$, where $slashed{E}_T$ represents the missing transverse energy from the neutrinos. In order to reconstruct the Higgs boson and top quark masses as well as to effectively remove the physics background, the collinear approximation for the highly boosted tau decays is employed. Our analysis suggests that a high energy LHC at $sqrt{s} = 27$ TeV will be able to discover this FCNH signal with an integrated luminosity $mathcal{L} = 3$ ab$^{-1}$ for a branching fraction ${cal B}(t to ch^0) agt 1.4 times 10^{-4}$ that corresponds to a FCNH coupling $|lambda_{tch}| agt 0.023$. This FCNH coupling is significantly below the current ATLAS combined upper limit of $|lambda_{tch}| = 0.064$.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87936425","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 : 2020-12-15DOI: 10.1103/PHYSREVD.103.054011
M. Greif, C. Greiner, S. Plätzer, B. Schenke, S. Schlichting
Following an explicit example, we present the chain of steps required for an event-by-event description of hadron production in high energy hadronic and nuclear collisions. We start from incoming nuclei, described in the Color Glass Condensate effective theory, whose collision creates the gluon fields of the glasma. Individual gluons are then sampled from the gluon fields' Husimi (smeared Wigner) distributions, and clustered using a new spacetime based algorithm. Clusters are fed into the Herwig event generator, which performs the hadronization, conserving energy and momentum. We discuss the physical implications of smearing and problems with the quasi particle picture for the studied processes. We compute spectra of charged hadrons and identified particles and their azimuthal momentum anisotropies, and address systematic uncertainties on observables, resulting from the general lack of detailed knowledge of the hadronization mechanism.
{"title":"Hadronization of correlated gluon fields","authors":"M. Greif, C. Greiner, S. Plätzer, B. Schenke, S. Schlichting","doi":"10.1103/PHYSREVD.103.054011","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.054011","url":null,"abstract":"Following an explicit example, we present the chain of steps required for an event-by-event description of hadron production in high energy hadronic and nuclear collisions. We start from incoming nuclei, described in the Color Glass Condensate effective theory, whose collision creates the gluon fields of the glasma. Individual gluons are then sampled from the gluon fields' Husimi (smeared Wigner) distributions, and clustered using a new spacetime based algorithm. Clusters are fed into the Herwig event generator, which performs the hadronization, conserving energy and momentum. We discuss the physical implications of smearing and problems with the quasi particle picture for the studied processes. We compute spectra of charged hadrons and identified particles and their azimuthal momentum anisotropies, and address systematic uncertainties on observables, resulting from the general lack of detailed knowledge of the hadronization mechanism.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"29 Pt 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80362624","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 : 2020-12-15DOI: 10.1103/PHYSREVD.103.014019
M. Broilo, D. A. Fagundes, E. Luna, M. Pel'aez
The LHC has released precise measurements of elastic proton-proton scattering that provide a unique constraint on the asymptotic behavior of the scattering amplitude at high energies. Recent reanalyses of part of these data indicate that the central values of some forward quantities would be different than initially observed. We introduce correlation information between the original and the reanalyzed data sets in a way suitable for a global fitting analysis of all data. The careful treatment of correlated errors leads to much less stringent limits on the $rho$ uncertainty and sets up the stage for describing the forward data using a scattering amplitude dominated by only crossing-even terms. In the light of these correlated data we determine the parameters of the soft Pomeron from the Regge theory. We use Born-level and eikonalized amplitudes. In the Born-level case we estimate the contribution of the double Pomeron exchange, while in the latter case we investigate the role of the eikonalization in both the one- and two-channel models. The role of the proton-Pomeron vertex form and of the nearest $t$-channel singularity in the Pomeron trajectory receive particular attention. We discuss the implications of our results and present predictions for the total cross section and the $rho$ parameter in proton-proton collisions at LHC and cosmic-ray energies.
{"title":"Soft Pomeron in light of the LHC correlated data","authors":"M. Broilo, D. A. Fagundes, E. Luna, M. Pel'aez","doi":"10.1103/PHYSREVD.103.014019","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.014019","url":null,"abstract":"The LHC has released precise measurements of elastic proton-proton scattering that provide a unique constraint on the asymptotic behavior of the scattering amplitude at high energies. Recent reanalyses of part of these data indicate that the central values of some forward quantities would be different than initially observed. We introduce correlation information between the original and the reanalyzed data sets in a way suitable for a global fitting analysis of all data. The careful treatment of correlated errors leads to much less stringent limits on the $rho$ uncertainty and sets up the stage for describing the forward data using a scattering amplitude dominated by only crossing-even terms. In the light of these correlated data we determine the parameters of the soft Pomeron from the Regge theory. We use Born-level and eikonalized amplitudes. In the Born-level case we estimate the contribution of the double Pomeron exchange, while in the latter case we investigate the role of the eikonalization in both the one- and two-channel models. The role of the proton-Pomeron vertex form and of the nearest $t$-channel singularity in the Pomeron trajectory receive particular attention. We discuss the implications of our results and present predictions for the total cross section and the $rho$ parameter in proton-proton collisions at LHC and cosmic-ray energies.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80858313","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 : 2020-12-14DOI: 10.1103/PHYSREVD.103.034030
Phillip Lakaschus, M. Buballa, D. Rischke
We study the phase structure of the two-flavor Nambu--Jona-Lasinio (NJL) model in the chiral limit, extending a previous study of the competition of an inhomogeneous chiral phase and a two-flavor color-superconducting (2SC) phase [1, 2]. There, an analytic expression for the dispersion relations for quasiparticle excitations in the presence of both a particular inhomogeneous chiral condensate, the so-called chiral density wave (CDW), and a homogeneous 2SC condensate was found. In this work we show how to determine the dispersion relations for arbitrary modulations of the chiral condensate in the presence of a homogeneous 2SC condensate, if the dispersion relations in the absence of color superconductivity are known. In our calculations, we employ two different Ans"atze for the inhomogeneous chiral condensate, the CDW as well as the real-kink crystal (RKC). Depending on the value of the diquark coupling we find a region of the phase diagram where the inhomogeneous chiral and the 2SC condensates coexist, confirming results of Refs. [1, 2]. Decreasing the diquark coupling favors the inhomogeneous phase over the coexistence phase. On the other hand, increasing the diquark coupling leads to a larger 2SC phase, while the inhomogeneous chiral and the coexistence phases become smaller. In agreement with previous studies the RKC Ansatz is energetically preferred over the CDW Ansatz. Both Ans"atze lead to a qualitatively similar phase diagram, however the coexistence phase is smaller for the RKC Ansatz.
{"title":"Competition of inhomogeneous chiral phases and two-flavor color superconductivity in the NJL model","authors":"Phillip Lakaschus, M. Buballa, D. Rischke","doi":"10.1103/PHYSREVD.103.034030","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.034030","url":null,"abstract":"We study the phase structure of the two-flavor Nambu--Jona-Lasinio (NJL) model in the chiral limit, extending a previous study of the competition of an inhomogeneous chiral phase and a two-flavor color-superconducting (2SC) phase [1, 2]. There, an analytic expression for the dispersion relations for quasiparticle excitations in the presence of both a particular inhomogeneous chiral condensate, the so-called chiral density wave (CDW), and a homogeneous 2SC condensate was found. In this work we show how to determine the dispersion relations for arbitrary modulations of the chiral condensate in the presence of a homogeneous 2SC condensate, if the dispersion relations in the absence of color superconductivity are known. In our calculations, we employ two different Ans\"atze for the inhomogeneous chiral condensate, the CDW as well as the real-kink crystal (RKC). Depending on the value of the diquark coupling we find a region of the phase diagram where the inhomogeneous chiral and the 2SC condensates coexist, confirming results of Refs. [1, 2]. Decreasing the diquark coupling favors the inhomogeneous phase over the coexistence phase. On the other hand, increasing the diquark coupling leads to a larger 2SC phase, while the inhomogeneous chiral and the coexistence phases become smaller. In agreement with previous studies the RKC Ansatz is energetically preferred over the CDW Ansatz. Both Ans\"atze lead to a qualitatively similar phase diagram, however the coexistence phase is smaller for the RKC Ansatz.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"142 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80611458","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 : 2020-12-14DOI: 10.1103/PHYSREVD.103.L051502
A. Bhattacharya, J. Cudell, Rami Oueslati, A. Vanthieghem
We study the consequences of high-energy collider data on the best fits to total, elastic, and inelastic cross sections for $pp$ and $pbar{p}$ scattering using two very distinct unitarisation schemes: the eikonal and the $U$-matrix. Despite their analytic differences, we find that the two schemes lead to almost identical predictions up to EeV energies, with differences only becoming significant at GUT-scale and higher energies.
{"title":"Proton inelastic cross section at ultrahigh energies","authors":"A. Bhattacharya, J. Cudell, Rami Oueslati, A. Vanthieghem","doi":"10.1103/PHYSREVD.103.L051502","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.L051502","url":null,"abstract":"We study the consequences of high-energy collider data on the best fits to total, elastic, and inelastic cross sections for $pp$ and $pbar{p}$ scattering using two very distinct unitarisation schemes: the eikonal and the $U$-matrix. Despite their analytic differences, we find that the two schemes lead to almost identical predictions up to EeV energies, with differences only becoming significant at GUT-scale and higher energies.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86576431","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 : 2020-12-14DOI: 10.21468/SCIPOSTPHYS.10.4.089
Mathias Backes, A. Butter, T. Plehn, R. Winterhalder
Event generation with neural networks has seen significant progress recently. The big open question is still how such new methods will accelerate LHC simulations to the level required by upcoming LHC runs. We target a known bottleneck of standard simulations and show how their unweighting procedure can be improved by generative networks. This can, potentially, lead to a very significant gain in simulation speed.
{"title":"How to GAN Event Unweighting","authors":"Mathias Backes, A. Butter, T. Plehn, R. Winterhalder","doi":"10.21468/SCIPOSTPHYS.10.4.089","DOIUrl":"https://doi.org/10.21468/SCIPOSTPHYS.10.4.089","url":null,"abstract":"Event generation with neural networks has seen significant progress recently. The big open question is still how such new methods will accelerate LHC simulations to the level required by upcoming LHC runs. We target a known bottleneck of standard simulations and show how their unweighting procedure can be improved by generative networks. This can, potentially, lead to a very significant gain in simulation speed.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83761898","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 : 2020-12-14DOI: 10.1103/PhysRevD.103.094019
P. Copeland, C. Ji, W. Melnitchouk
The self-energies of the full set of flavor SU(3) octet and decuplet baryons are computed within a relativistic chiral effective theory framework. The leading nonanalytic chiral behavior is derived for the octet and decuplet masses, and a finite-range regularization consistent with Lorentz and gauge invariance is applied to account for the finite size of the baryons. Using a four-dimensional dipole form factor, the relative importance of various meson-baryon loop contributions to the self-energies is studied numerically as a function of the dipole range parameter and meson mass, and comparison is made between the relativistic results and earlier approximations within the heavy baryon limit.
{"title":"Octet and decuplet baryon self-energies in relativistic SU(3) chiral effective theory","authors":"P. Copeland, C. Ji, W. Melnitchouk","doi":"10.1103/PhysRevD.103.094019","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.094019","url":null,"abstract":"The self-energies of the full set of flavor SU(3) octet and decuplet baryons are computed within a relativistic chiral effective theory framework. The leading nonanalytic chiral behavior is derived for the octet and decuplet masses, and a finite-range regularization consistent with Lorentz and gauge invariance is applied to account for the finite size of the baryons. Using a four-dimensional dipole form factor, the relative importance of various meson-baryon loop contributions to the self-energies is studied numerically as a function of the dipole range parameter and meson mass, and comparison is made between the relativistic results and earlier approximations within the heavy baryon limit.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88136965","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 : 2020-12-13DOI: 10.1103/PhysRevD.103.114021
S. Nedelko, V. Voronin
An impact of the finite size effects on the vacuum free energy density of full QCD with $N_{rm f}$ massless flavors in the presence of homogeneous (anti-)self-dual Abelian background gluon field is studied. The zero temperature free energy density of the four-dimensional spherical domain is computed as a function of the background field strength $B$ and domain radius $R$. Calculation is performed in the one-loop approximation improved by accounting for mixing of the quark and gluon quasi-zero modes with normal modes, with the use of the $zeta$-function regularization. It is indicated that, under plausible assumption on the character of the mixing, the quantum correction to the free energy density has a minimum as a function of $B$ and $R$. Within the mean field approach to QCD vacuum based on domain wall network representation of the mean field, an existence of the minimum may prevent infinite growth of individual domain, thus protecting the vacuum from the long-range ordering, and, hence, serving as the origin of disorder in the statistical ensemble of domain wall networks, driven by the minimization of the overall free energy of the dominant gauge field configurations.
{"title":"Energy-driven disorder in mean field QCD","authors":"S. Nedelko, V. Voronin","doi":"10.1103/PhysRevD.103.114021","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.114021","url":null,"abstract":"An impact of the finite size effects on the vacuum free energy density of full QCD with $N_{rm f}$ massless flavors in the presence of homogeneous (anti-)self-dual Abelian background gluon field is studied. The zero temperature free energy density of the four-dimensional spherical domain is computed as a function of the background field strength $B$ and domain radius $R$. Calculation is performed in the one-loop approximation improved by accounting for mixing of the quark and gluon quasi-zero modes with normal modes, with the use of the $zeta$-function regularization. It is indicated that, under plausible assumption on the character of the mixing, the quantum correction to the free energy density has a minimum as a function of $B$ and $R$. Within the mean field approach to QCD vacuum based on domain wall network representation of the mean field, an existence of the minimum may prevent infinite growth of individual domain, thus protecting the vacuum from the long-range ordering, and, hence, serving as the origin of disorder in the statistical ensemble of domain wall networks, driven by the minimization of the overall free energy of the dominant gauge field configurations.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86778612","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 : 2020-12-13DOI: 10.1103/PHYSREVD.103.054026
Ahmad Jamali Hafshejani, A. Mirjalili
We propose a mass-dependent MOM scheme to renormalize UV divergence of unpolarized PDFs at one-loop order. This approach which is based on a once subtracted dispersion relation does not need any regulator. The overall counterterms are obtained from the imaginary part of large transverse momentum region in loop integrals. The mass-dependent characteristic of the scheme yields to mass-dependent splitting functions for the DGLAP evolution equations. While the flavor number is fixed at any renormalization scale, the decoupling theorem is automatically imposed by the mass-dependent splitting functions. The required symmetries are also automatically respected by our prescription.
{"title":"Mass corrections to the DGLAP equations","authors":"Ahmad Jamali Hafshejani, A. Mirjalili","doi":"10.1103/PHYSREVD.103.054026","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.054026","url":null,"abstract":"We propose a mass-dependent MOM scheme to renormalize UV divergence of unpolarized PDFs at one-loop order. This approach which is based on a once subtracted dispersion relation does not need any regulator. The overall counterterms are obtained from the imaginary part of large transverse momentum region in loop integrals. The mass-dependent characteristic of the scheme yields to mass-dependent splitting functions for the DGLAP evolution equations. While the flavor number is fixed at any renormalization scale, the decoupling theorem is automatically imposed by the mass-dependent splitting functions. The required symmetries are also automatically respected by our prescription.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"341 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76911779","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 : 2020-12-11DOI: 10.1103/PHYSREVD.103.035026
Shinsuke Kawai, N. Okada, S. Okada
A scalar field having the Coleman-Weinberg type effective potential arises in various contexts of particle physics and serves as a useful framework for discussing cosmic inflation. According to recent studies based on the Markov chain Monte Carlo analysis, the coefficients of such an effective potential are severely constrained by the cosmological data. We investigate the impact of this observation on the physics beyond the Standard Model, focusing on an inflationary model based on the $U(1)_X$-extended Standard Model as a well-motivated example. We examine the parameter region that is not excluded by the Large Hadron Collider (LHC) Run-2 at 139 fb${}^{-1}$ integrated luminosity, and show that the model parameters can be further constrained by the High-Luminosity LHC experiments in the near future. We also comment on the possible reheating mechanism and the dark matter candidates of this scenario.
{"title":"Low-energy implications of cosmological data in \u0000U(1)X\u0000 Higgs inflation","authors":"Shinsuke Kawai, N. Okada, S. Okada","doi":"10.1103/PHYSREVD.103.035026","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.035026","url":null,"abstract":"A scalar field having the Coleman-Weinberg type effective potential arises in various contexts of particle physics and serves as a useful framework for discussing cosmic inflation. According to recent studies based on the Markov chain Monte Carlo analysis, the coefficients of such an effective potential are severely constrained by the cosmological data. We investigate the impact of this observation on the physics beyond the Standard Model, focusing on an inflationary model based on the $U(1)_X$-extended Standard Model as a well-motivated example. We examine the parameter region that is not excluded by the Large Hadron Collider (LHC) Run-2 at 139 fb${}^{-1}$ integrated luminosity, and show that the model parameters can be further constrained by the High-Luminosity LHC experiments in the near future. We also comment on the possible reheating mechanism and the dark matter candidates of this scenario.","PeriodicalId":8457,"journal":{"name":"arXiv: High Energy Physics - Phenomenology","volume":"167 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77514898","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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