Physical Review D最新文献

{"title":"Investigation of Λc→(Λ,n)ℓ+νℓ decays in the standard model and beyond","authors":"Zhi-Hua Zhang, Ying Li","doi":"10.1103/physrevd.111.053008","DOIUrl":"https://doi.org/10.1103/physrevd.111.053008","url":null,"abstract":"In this work, we study the decays Λ</a:mi>c</a:mi></a:msub>→</a:mo>(</a:mo>Λ</a:mi>,</a:mo>n</a:mi>)</a:mo>ℓ</a:mo>+</a:mo></a:msup>ν</a:mi>ℓ</a:mo></a:msub></a:math> (<h:math xmlns:h=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><h:mo>ℓ</h:mo><h:mo>=</h:mo><h:mi>μ</h:mi></h:math>, <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:mrow><j:mi>e</j:mi></j:mrow></j:math>) within a model-independent framework. We calculate the helicity amplitudes for all possible four-fermion operators, including the interactions between different new physics (NP) operators. The form factors for the <l:math xmlns:l=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><l:msub><l:mi mathvariant=\"normal\">Λ</l:mi><l:mi>c</l:mi></l:msub><l:mo stretchy=\"false\">→</l:mo><l:mo stretchy=\"false\">(</l:mo><l:mi mathvariant=\"normal\">Λ</l:mi><l:mo>,</l:mo><l:mi>n</l:mi><l:mo stretchy=\"false\">)</l:mo></l:math> transitions are taken from lattice QCD calculations. We present detailed results for the branching fractions and other key observables. Although our results are generally consistent with previous studies, we find that the predicted central values for the branching fractions are approximately 10% larger than the experimental measurements. Additionally, we explore the potential impacts of NP, focusing particularly on the scenario in which NP particles couple exclusively to the muon. Using Wilson coefficients fitted from <s:math xmlns:s=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><s:mi>D</s:mi></s:math> and <u:math xmlns:u=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><u:msub><u:mi>D</u:mi><u:mi>s</u:mi></u:msub></u:math> meson decays, we examine NP effects in the <w:math xmlns:w=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><w:msub><w:mi mathvariant=\"normal\">Λ</w:mi><w:mi>c</w:mi></w:msub><w:mo stretchy=\"false\">→</w:mo><w:mo stretchy=\"false\">(</w:mo><w:mi mathvariant=\"normal\">Λ</w:mi><w:mo>,</w:mo><w:mi>n</w:mi><w:mo stretchy=\"false\">)</w:mo><w:msup><w:mi>μ</w:mi><w:mo>+</w:mo></w:msup><w:msub><w:mi>ν</w:mi><w:mi>μ</w:mi></w:msub></w:math> decay channels. It is found that although most potential contributions of NP are obscured by the uncertainties inherent in both theory and experiment, the right-handed scalar operator could suppress the branching fraction of <db:math xmlns:db=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><db:mrow><db:msub><db:mrow><db:mi mathvariant=\"normal\">Λ</db:mi></db:mrow><db:mrow><db:mi>c</db:mi></db:mrow></db:msub><db:mo stretchy=\"false\">→</db:mo><db:mo stretchy=\"false\">(</db:mo><db:mi mathvariant=\"normal\">Λ</db:mi><db:mo>,</db:mo><db:mi>n</db:mi><db:mo stretchy=\"false\">)</db:mo><db:msup><db:mrow><db:mi>μ</db:mi></db:mrow><db:mrow><db:mo>+</db:mo></db:mrow></db:msup><db:msub><db:mrow><db:mi>ν</db:mi></db:mrow><db:mrow><db:mi>μ</db:mi></db:mrow></db:msub></db:mrow></db:math> by up to 10%. We also highlight that the ratio of the forward-backward asymmetry in the <kb:math xmlns:kb=\"http://ww","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"12 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of metastable standard model particles from long-lived particle decays in the MeV primordial plasma","authors":"Kensuke Akita, Gideon Baur, Maksym Ovchynnikov, Thomas Schwetz, Vsevolod Syvolap","doi":"10.1103/physrevd.111.063542","DOIUrl":"https://doi.org/10.1103/physrevd.111.063542","url":null,"abstract":"We investigate the cosmological impact of hypothetical unstable new physics particles that decay in the MeV-scale plasma of the early Universe. Focusing on scenarios where the decays produce metastable species such as muons, pions, and kaons, we systematically analyze the dynamics of these particles using coupled Boltzmann equations governing their abundances. Our results demonstrate that the metastable species can efficiently annihilate or interact with nucleons, often leading to their disappearance before decay. The suppression of decay significantly alters the properties of cosmic neutrinos, impacting cosmological observables like big bang nucleosynthesis and the cosmic microwave background. To support further studies, we provide two public codes: the code that traces the evolution of these metastable particles, as well as the ython-based unintegrated neutrino Boltzmann solver that uses this evolution as an input and may be applied to a broad range of scenarios. We then utilize them for studying a few particular new physics models. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"35 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quasi-two-body B→P(K+K−,π+π−) decays with f0(980) resonance","authors":"Ya-Xin Wang, Jun-Peng Wang, Ying Li, Zhi-Tian Zou","doi":"10.1103/physrevd.111.053009","DOIUrl":"https://doi.org/10.1103/physrevd.111.053009","url":null,"abstract":"In this study, we investigate the C&lt;/a:mi&gt;P&lt;/a:mi&gt;&lt;/a:math&gt;-averaged branching fractions and direct &lt;c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;c:mi&gt;C&lt;/c:mi&gt;&lt;c:mi&gt;P&lt;/c:mi&gt;&lt;/c:math&gt; asymmetries in the quasi-two-body decays &lt;e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;e:mi&gt;B&lt;/e:mi&gt;&lt;e:mo stretchy=\"false\"&gt;→&lt;/e:mo&gt;&lt;e:mi&gt;P&lt;/e:mi&gt;&lt;e:mo stretchy=\"false\"&gt;(&lt;/e:mo&gt;&lt;e:msub&gt;&lt;e:mi&gt;f&lt;/e:mi&gt;&lt;e:mn&gt;0&lt;/e:mn&gt;&lt;/e:msub&gt;&lt;e:mo stretchy=\"false\"&gt;(&lt;/e:mo&gt;&lt;e:mn&gt;980&lt;/e:mn&gt;&lt;e:mo stretchy=\"false\"&gt;)&lt;/e:mo&gt;&lt;e:mo stretchy=\"false\"&gt;→&lt;/e:mo&gt;&lt;e:mo stretchy=\"false\"&gt;)&lt;/e:mo&gt;&lt;e:mo stretchy=\"false\"&gt;(&lt;/e:mo&gt;&lt;e:msup&gt;&lt;e:mi&gt;K&lt;/e:mi&gt;&lt;e:mo&gt;+&lt;/e:mo&gt;&lt;/e:msup&gt;&lt;e:msup&gt;&lt;e:mi&gt;K&lt;/e:mi&gt;&lt;e:mo&gt;−&lt;/e:mo&gt;&lt;/e:msup&gt;&lt;e:mo&gt;,&lt;/e:mo&gt;&lt;e:msup&gt;&lt;e:mi&gt;π&lt;/e:mi&gt;&lt;e:mo&gt;+&lt;/e:mo&gt;&lt;/e:msup&gt;&lt;e:msup&gt;&lt;e:mi&gt;π&lt;/e:mi&gt;&lt;e:mo&gt;−&lt;/e:mo&gt;&lt;/e:msup&gt;&lt;e:mo stretchy=\"false\"&gt;)&lt;/e:mo&gt;&lt;/e:math&gt; within the framework of the perturbative QCD approach, where &lt;o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;o:mi&gt;P&lt;/o:mi&gt;&lt;/o:math&gt; denotes light pseudoscalar mesons (&lt;q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;q:mi&gt;π&lt;/q:mi&gt;&lt;/q:math&gt;,&lt;s:math xmlns:s=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;s:mi&gt;K&lt;/s:mi&gt;&lt;/s:math&gt;). The timelike form factor &lt;u:math xmlns:u=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;u:msub&gt;&lt;u:mi&gt;F&lt;/u:mi&gt;&lt;u:mi&gt;S&lt;/u:mi&gt;&lt;/u:msub&gt;&lt;u:mo stretchy=\"false\"&gt;(&lt;/u:mo&gt;&lt;u:mi&gt;ω&lt;/u:mi&gt;&lt;u:mo stretchy=\"false\"&gt;)&lt;/u:mo&gt;&lt;/u:math&gt;, characterizing final-state interactions between collinear particles in the resonant region, is modeled through the revised relativistic Breit-Wigner formalism for the &lt;y:math xmlns:y=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;y:mi&gt;S&lt;/y:mi&gt;&lt;/y:math&gt;-wave f&lt;/ab:mi&gt;0&lt;/ab:mn&gt;&lt;/ab:msub&gt;(&lt;/ab:mo&gt;980&lt;/ab:mn&gt;)&lt;/ab:mo&gt;&lt;/ab:math&gt; resonance. Within the Gegenbauer moments of the &lt;eb:math xmlns:eb=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;eb:mi&gt;S&lt;/eb:mi&gt;&lt;/eb:math&gt;-wave two-meson distribution amplitudes constrained by current data, we predict the branching fractions of &lt;gb:math xmlns:gb=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;gb:mi&gt;B&lt;/gb:mi&gt;&lt;gb:mo stretchy=\"false\"&gt;→&lt;/gb:mo&gt;&lt;gb:mi&gt;P&lt;/gb:mi&gt;&lt;gb:mo stretchy=\"false\"&gt;(&lt;/gb:mo&gt;&lt;gb:msub&gt;&lt;gb:mi&gt;f&lt;/gb:mi&gt;&lt;gb:mn&gt;0&lt;/gb:mn&gt;&lt;/gb:msub&gt;&lt;gb:mo stretchy=\"false\"&gt;(&lt;/gb:mo&gt;&lt;gb:mn&gt;980&lt;/gb:mn&gt;&lt;gb:mo stretchy=\"false\"&gt;)&lt;/gb:mo&gt;&lt;gb:mo stretchy=\"false\"&gt;→&lt;/gb:mo&gt;&lt;gb:mo stretchy=\"false\"&gt;)&lt;/gb:mo&gt;&lt;gb:mo stretchy=\"false\"&gt;(&lt;/gb:mo&gt;&lt;gb:msup&gt;&lt;gb:mi&gt;K&lt;/gb:mi&gt;&lt;gb:mo&gt;+&lt;/gb:mo&gt;&lt;/gb:msup&gt;&lt;gb:msup&gt;&lt;gb:mi&gt;K&lt;/gb:mi&gt;&lt;gb:mo&gt;−&lt;/gb:mo&gt;&lt;/gb:msup&gt;&lt;gb:mo&gt;,&lt;/gb:mo&gt;&lt;gb:msup&gt;&lt;gb:mi&gt;π&lt;/gb:mi&gt;&lt;gb:mo&gt;+&lt;/gb:mo&gt;&lt;/gb:msup&gt;&lt;gb:msup&gt;&lt;gb:mi&gt;π&lt;/gb:mi&gt;&lt;gb:mo&gt;−&lt;/gb:mo&gt;&lt;/gb:msup&gt;&lt;gb:mo stretchy=\"false\"&gt;)&lt;/gb:mo&gt;&lt;/gb:math&gt; to lie in the range of &lt;qb:math xmlns:qb=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;qb:msup&gt;&lt;qb:mn&gt;10&lt;/qb:mn&gt;&lt;qb:mrow&gt;&lt;qb:mo&gt;−&lt;/qb:mo&gt;&lt;qb:mn&gt;8&lt;/qb:mn&gt;&lt;/qb:mrow&gt;&lt;/qb:msup&gt;&lt;/qb:math&gt; to &lt;sb:math xmlns:sb=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;sb:msup&gt;&lt;","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"23 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collective dynamics in heavy and light-ion collisions. II. Determining the origin of collective behavior in high-energy collisions","authors":"Victor E. Ambruş, S. Schlichting, C. Werthmann","doi":"10.1103/physrevd.111.054025","DOIUrl":"https://doi.org/10.1103/physrevd.111.054025","url":null,"abstract":"Exploiting the first measurements of the same ion species in OO collisions at the Relativistic Heavy Ion Collider (RHIC) and LHC, we propose an observable to distinguish whether collective behavior builds up through a hydrodynamic expansion of a strongly interacting quark-gluon plasma or few final state rescatterings. Our procedure allows one to disentangle the effects of the initial state geometry and the dynamical response mechanism on anisotropic flow. We validate its ability to discriminate between systems with different interaction rates using results from event-by-event simulations in kinetic theory. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"183 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining fermionic condensates","authors":"Gergely Endrődi, Tamás G. Kovács, Gergely Markó, Laurin Pannullo","doi":"10.1103/physrevd.111.054512","DOIUrl":"https://doi.org/10.1103/physrevd.111.054512","url":null,"abstract":"We study spontaneous symmetry breaking in quantum field theories with fermionic order parameters and construct, for the first time in the literature, the constraint effective potential for it. The Grassmann-valued constraint we encounter is handled using its large-volume expansion, corresponding to a saddle-point approximation. We test the method in the chiral Gross-Neveu model and demonstrate its consistency with the standard approach. The machinery we developed opens up a new avenue to investigate the spontaneous symmetry breaking and restoration in field theories, in particular for the chiral symmetry breaking in the strong interactions. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"18 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Minimal dark matter in SU(5) grand unification","authors":"Takashi Toma","doi":"10.1103/physrevd.111.l051701","DOIUrl":"https://doi.org/10.1103/physrevd.111.l051701","url":null,"abstract":"Minimal dark matter is an attractive candidate for dark matter because it is stabilized without the need to impose additional symmetries. It is known that the S</a:mi>U</a:mi>(</a:mo>2</a:mn>)</a:mo>L</a:mi></a:msub></a:math> quintuplet fermion can serve as a minimal dark matter candidate, with its mass predicted to be around 14 TeV, based on the thermal production mechanism. In this work, we embed the quintuplet dark matter within nonsupersymmetric <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mi>S</e:mi><e:mi>U</e:mi><e:mo stretchy=\"false\">(</e:mo><e:mn>5</e:mn><e:mo stretchy=\"false\">)</e:mo></e:math> grand unified theories. We find that two pairs of colored sextet fermions are required at the <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mrow><i:mi mathvariant=\"script\">O</i:mi><i:mo stretchy=\"false\">(</i:mo><i:mn>1</i:mn><i:mi>–</i:mi><i:mn>10</i:mn><i:mo stretchy=\"false\">)</i:mo><i:mtext> </i:mtext><i:mtext> </i:mtext><i:mi>TeV</i:mi></i:mrow></i:math> scale to achieve gauge coupling unification, with the unification scale near the reduced Planck scale. These colored sextet fermions become metastable because their interactions are suppressed by the unification scale. Our model can be tested through comprehensive searches for colored sextet fermions in collider experiments, as well as through indirect and direct detection methods for minimal dark matter. Once the minimal dark matter scenario has been experimentally confirmed, it will have implications for modifying string theories. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"21 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Attenuation of boosted dark matter in two component dark matter scenario","authors":"Nilanjana Kumar, Gaadha Lekshmi","doi":"10.1103/physrevd.111.055022","DOIUrl":"https://doi.org/10.1103/physrevd.111.055022","url":null,"abstract":"Boosted dark matter constitutes a small fraction of the total dark matter in the Universe, with mass ranging from eV to MeV and often exhibiting (semi)relativistic velocity. Hence the likelihood of detecting boosted dark matter in Earth-based direct detection experiments is relatively high. There is more than one explanation for the origin of the boosted dark matter including the two-component dark matter models where the heavier dark matter species(dominant) annihilates to nearly monoenergetic light dark matter particles (subdominant) in the galactic halo. If the dominant dark matter species is heavier (MeV-GeV), the subdominant light dark matter achieves (semi)relativistic velocity or . These boosted dark matter particles suffer from scattering with electrons and nuclei while crossing the atmosphere and the Earth’s crust before reaching underground experiments and hence the kinetic energy of the dark matter is attenuated. In the two-component dark matter framework, we examine how the boost of the dark matter influences the attenuation of kinetic energy across a broad spectrum of dark matter masses. We perform a detailed study at various DM-electron and DM-nucleus cross sections including the effect of nuclear form factor and elastic and inelastic scattering (for large kinetic energy). For a 10 MeV boosted dark matter with boost ∼</a:mo>10</a:mn>−</a:mo>100</a:mn></a:mrow></a:math>, the effect of DM-electron scattering is found to be severe than the DM-nucleus scattering (with form factor) if DM-nucleon scattering cross section is <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:msup><c:mn>10</c:mn><c:mrow><c:mo>−</c:mo><c:mn>29</c:mn></c:mrow></c:msup><c:mtext> </c:mtext><c:mtext> </c:mtext><c:msup><c:mrow><c:mi>cm</c:mi></c:mrow><c:mrow><c:mn>2</c:mn></c:mrow></c:msup></c:math>. We also show how the peak position of the boosted dark matter flux shifts due to the attenuation of its kinetic energy. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"96 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collective dynamics in heavy and light-ion collisions. I. Kinetic theory vs hydrodynamics","authors":"Victor E. Ambruş, S. Schlichting, C. Werthmann","doi":"10.1103/physrevd.111.054024","DOIUrl":"https://doi.org/10.1103/physrevd.111.054024","url":null,"abstract":"High-energy nuclear collisions exhibit collective flow, which emerges as a dynamical response of the quark-gluon plasma (QGP) to the initial state geometry of the collision. Collective flow in heavy-ion collisions is usually described within multistage evolution models, which employ a viscous relativistic hydrodynamic description of the space-time evolution of the QGP. By comparing event-by-event simulations in kinetic theory and viscous hydrodynamics in OO, AuAu and PbPb collisions at energies of the Relativistic Heavy Ion Collider (RHIC) and of LHC, we quantify to what extent a macroscopic hydrodynamic description can accurately describe the development of collective flow and to what extent collective flow in small systems, such as OO, is sensitive to the nonequilibrium evolution of the QGP beyond hydrodynamics. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"20 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One-loop off-shell quark-gluon vertex in arbitrary gauge and dimensions: A streamlined approach through the second-order formalism of QCD","authors":"Victor Miguel Banda Guzmán, A. Bashir","doi":"10.1103/physrevd.111.056025","DOIUrl":"https://doi.org/10.1103/physrevd.111.056025","url":null,"abstract":"The standard Feynman rules used for perturbative calculations in quantum chromodynamics (QCD) are derived from a Lagrangian that is first-order in derivatives. It includes a three-point quark-gluon vertex which obscures the precise disentangled manner in which spin and momentum are interchanged during these interactions. An unambiguous understanding of this interchange is insightful for efficiently extracting physically relevant information from various Green’s functions. To separate the scalar and spin degrees of freedom and gain physical insight from the outset, we examine the quark-gluon vertex using the less commonly employed second-order formalism of QCD. We compute this off-shell vertex in arbitrary space-time dimensions and covariant gauges by using scalar integrals with shifted dimensions, which include higher powers of the propagators, within a combined first- and second-order formalism. This approach naturally identifies the transverse components of the quark-gluon vertex, even before evaluating the tensor Feynman integrals. Our results are in complete agreement with those obtained from the first-order formalism. We also compute the on-shell version of this vertex using exclusively the second-order formalism, facilitating a precise identification of spin and momentum interchange. Through analyzing the Pauli form factor at k</a:mi>2</a:mn></a:msup>=</a:mo>0</a:mn></a:math> (where <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mi>k</c:mi></c:math> represents the momentum of the external gluon), we find that only a specific set of second-order Feynman diagrams are relevant for calculating the electromagnetic and chromomagnetic dipole moments. These diagrams represent quantum processes in which the spin of the incoming quark changes only once due to interactions with the virtual gluons that form the quark-gluon vertex. All other interactions involve only momentum interchange (scalar interactions). Furthermore, we confirm existing results in the literature, which suggest that defining the chromomagnetic dipole moment in the limit <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:msup><e:mi>k</e:mi><e:mn>2</e:mn></e:msup><e:mo stretchy=\"false\">→</e:mo><e:mn>0</e:mn></e:math> leads to infrared divergences. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"71 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smeared end-of-the-world branes","authors":"William Harvey, Kristan Jensen, Takahiro Uzu","doi":"10.1103/physrevd.111.066017","DOIUrl":"https://doi.org/10.1103/physrevd.111.066017","url":null,"abstract":"We uncover new nonsupersymmetric boundary conditions in 10- and 11-dimensional supergravity whereby spacetime ends on a smeared distribution of D- and M-branes, respectively. For example, we find a solution of type IIB supergravity where the AdS</a:mi></a:mrow>5</a:mn></a:mrow></a:msub>×</a:mo>S</a:mi>5</a:mn></a:msup></a:mrow></a:math> vacuum ends on an <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><d:mi>S</d:mi><d:mi>O</d:mi><d:mo stretchy=\"false\">(</d:mo><d:mn>6</d:mn><d:mo stretchy=\"false\">)</d:mo></d:math>-invariant distribution of D3-branes. These distributions give a stringy completion of simple models of tensionful end-of-the-world branes considered previously in the literature. However, we find that our solutions are all unstable to the fragmentation of the end-of-the-world brane into its constituents. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"28 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}