Tue·Dec 12, 2023Tuesday·December 12, 2023

1. 01*

   A Constituent Model of Light Hybrid Meson Decays

   C. Farina🇺🇸 · E.S. Swanson🇺🇸

   A model of light hybrid mesons and their strong decays is developed. The model employs a gluonic quasiparticle to describe low energy gluodynamics and uses the QCD Hamiltonian in Coulomb gauge to guide the construction of states and decay amplitudes. We compute the partial widths of the twelve low lying isovector and vector hybrids. Implications of these results on hybrid searches are also made, with the chief conclusions being that direct observation of the vector states will be difficult, that a hybrid $\pi (1800)$ has distinctive decay characteristics, a narrow $\eta (1900)$ hybrid should exist, an ${\eta }_1(1750)$ should be sought, and that the exotic nature of $J^{PC}=2^{-+}$ hybrid mesons should be discernible with sufficient data. We argue that the isovector ${\pi }_2$ hybrid has been discovered, giving a total of four possible hybrid mesons, ${\pi }_1(1600)$, ${\eta }_1(1855)$, $\pi (1800)$, and ${\pi }_2(2360)$, which appear to be filling out the lowlying hybrid supermultiplet in the expected fashion.

   hep-phPRD(2024)·10 citations
2. 02*

   Production of the $X(4014)$ as the spin-2 partner of $X(3872)$ in $e^{+}{e}^{-}$ collisions

   Pan-Pan Shi🇨🇳 · Vadim Baru🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Alexey Nefediev🇸🇮

   In 2021, the Belle collaboration reported the first observation of a new structure in the $\psi (2S)\gamma$ final state produced in the two-photon fusion process. In the hadronic molecule picture, this new structure can be associated with the shallow isoscalar $D^{\ast }{\bar{D}}^{\ast }$ bound state and as such is an excellent candidate for the spin-2 partner of the $X(3872)$ with the quantum numbers $J^{PC}=2^{++}$ conventionally named $X_2$. In this work we evaluate the electronic width of this new state and argue that its nature is sensitive to its total width, the experimental measurement currently available being unable to distinguish between different options. Our estimates demonstrate that the planned Super $\tau$-Charm Facility offers a promising opportunity to search for and study this new state in the invariant mass distributions for the final states $J/\psi \gamma$ and $\psi (2S)\gamma$.

   hep-phhep-exnucl-thChin.Phys.Lett.(2024)·14 citations
3. 03*

   Energy and system size dependence of strongly intensive fluctuation measures in heavy-ion collisions at FAIR energies

   Bushra Ali🇮🇳 · Shakeel Ahmad🇮🇳 · A. Ahmad🇮🇳

   Event-by-event fluctuations of multiplicity and transverse momentum of charged hadrons produced in heavy-ion collisions at FAIR energies, 10A, 20A, 30A and 40A GeV are studied in the framework of relativistic transport model, URQMD. Dependence of two families of strongly intensive measures of multiplicity($N$) and transverse momentum($p_{\mathrm{T}}$) fluctuations, $\Delta [p_{\mathrm{T}},N]$ and $\Sigma [p_{\mathrm{T}},N]$, on collision centrality, centrality bin-widths and pseudorapidity windows are examined. Attempts are also made to study $NN$, $N$$p_{\mathrm{T}}$ and $p_{\mathrm{T}}$$p_{\mathrm{T}}$ fluctuations using two window analysis method. The findings suggest that the measure, $\Delta [p_{\mathrm{T}},N]$ be dealt with proper selection of centrality intervals. This measure also exhibits a strong dependence on the widths of $\eta$ windows. The variable $\Sigma [p_{\mathrm{T}},N]$, however, is observed to be insensitive to the centrality bin-widths and shows a variation of $<5\%$ with the widths of $\eta$ windows. The analysis of data after event mixing gives $\Delta [p_{\mathrm{T}},N]$ and $\Sigma [p_{\mathrm{T}},N]$ values as $\sim 1$ irrespective of the widths of $\eta$ windows and collision centrality, as predicted by model of independent particle emission, IPM. The study of joint fluctuations of the two quantities on two $\eta$ windows separated in $\eta$ space, reveals that $\Sigma [N_{\mathrm{F}},N_{\mathrm{B}}]$ values are $\sim 1$ irrespective of the position of $\eta$ windows whereas, the values of $\Sigma [N_{\mathrm{F}},p_{{\mathrm{T}}_{\mathrm{B}}}]$ and $\Sigma [p_{{\mathrm{T}}_{\mathrm{F}}},p_{{\mathrm{T}}_{\mathrm{B}}}]$ firstly increase with ${\eta }_{sep}$ and later acquire saturations. The observed trend of centrality dependence of $\Sigma [N_{\mathrm{F}},N_{\mathrm{B}}],\Sigma [N_{\mathrm{F}},p_{{\mathrm{T}}_{\mathrm{B}}}]$ and $\Sigma [p_{{\mathrm{T}}_{\mathrm{F}}},p_{{\mathrm{T}}_{\mathrm{B}}}]$ agrees fairly well with those observed in MC simulated studies carried out for AA collisions at LHC energies in the framework model of string fusion.

   hep-phnucl-thJ.Phys.G(2024)·1 citation
4. 04*

   Rare K decays off and on the lattice

   Stefan Schacht🇬🇧 · Amarjit Soni🇺🇸

   The importance of rare $K$ decays especially in the context of a kaon unitarity triangle (KUT) is emphasized. The decay $K_L\to {\pi }^0\nu \bar{\nu }$ is theoretically very clean but experimentally extremely challenging. The Standard Model prediction $\mathcal{B}\sim 3\times 10^{-11}$ is still about two orders of magnitude away from the current experimental upper bound. One way to continue to make progress towards the construction of a KUT is by improving the accuracy in the calculation of ${\epsilon }^{\prime }$. Another way which is the primary focus here is via studies of $K^0\to {\pi }^0{\mu }^{+}{\mu }^{-}$. LHCb, J-PARC, the proposed HIKE project, phenomenology, and in fact precision studies on the lattice can all play a very important role in this context.

   hep-phhep-latPoS(2024)·2 citations
5. 05*

   Factorization and resummation at next-to-leading-power

   Leonardo Vernazza🇮🇹

   We discuss recent progress concerning the resummation of large logarithms at next-to-leading power (NLP) in scattering processes such as Drell-Yan and deep inelastic scattering near threshold, and thrust in the two-jet limit. We start by reviewing the approach based on soft-collinear effective field theory and show that the standard factorization into short distance coefficients, collinear and soft functions at NLP leads in general to the appearance of endpoint divergences, which prevent the naive application of resummation techniques based on the renormalization group. Taking thrust as a case study, we then show that these singularities are indeed an artifact of the effective theory, and discuss how they can be removed to recover a finite factorization theorem and achieve resummation at NLP, at LL accuracy. Last, we discuss recent work concerning the calculation of all collinear and soft functions necessary to reproduce Drell-Yan near threshold up to NNLO in perturbation theory. This calculation provides useful data to extend resummation at NLP beyond LL accuracy.

   hep-phPoS(2024)·3 citations
6. 06*

   A simple model for the charm structure function of nuclei

   G.R.Boroun🇮🇷

   In this paper, we have investigated the importance of quark charm in nuclear structure functions in the color dipole model at small $x$. The charm structure function per nucleon $F_2^{cA}/A$ for light and heavy nuclei in a wide range of transverse separations $\mathrm{r}$ with renormalization and factorization scales are considered. Bounds on the ratio $F_2^{cA}/A{F}_2^A$ for nuclei are well described with respect to the electron-ion future colliders kinematic range, i.e, EIC and EIcC colliders.

   hep-phPLB(2024)·5 citations
7. 07*

   Contributions of the subprocess $K_0^{\ast }(1430)\to K{\eta }^{\prime }$ in the charmless three-body $B$ meson decays

   Ai-Jun Ma🇨🇳 · Wen-Fei Wang🇨🇳

   We study the contributions for $K{\eta }^{\prime }$ pair originating from the scalar intermediate state $K_0^{\ast }(1430)$ in the three-body decays $B\to K{\eta }^{\prime }h$ ($h=\pi ,K$) within the perturbative QCD approach. The contribution of $K_0^{\ast }(1430)\to K{\eta }^{\prime }$ is described by the Flatt$\acute{\mathrm{e}}$ formula with coupled channels $K\pi$, $K\eta$ and $K{\eta }^{\prime }$. The strong coupling constants $g_{K_0^{\ast }K{\eta }^{(\prime )}}$ are extracted from $g_{K_0^{\ast }K\pi }$ within flavor SU$(3)$ symmetry. In spite of the strong depression by phase space near the threshold of $K{\eta }^{\prime }$, the $CP$ averaged branching fractions for the $B\to K_0^{\ast }(1430)h\to K{\eta }^{\prime }h$ decays are predicted to be on the order of $10^{-8}$ to $10^{-5}$, which are non-negligible for the corresponding three-body $B$ decays. Since the K$\eta$ system is almost decoupled from the even-spin strange mesons under flavor SU$(3)$ symmetry, those quasi-two-body $B$ decays with subprocess $K_0^{\ast }(1430)\to K\eta$ shall have quite small branching ratios and are not taken into account in this work. We also estimate that the branching fraction for $K_0^{\ast }(1430)\to K{\eta }^{\prime }$ is about one fifth of that for $K_0^{\ast }(1430)\to K\pi$. The predictions for the relevant decays are expected to be tested by the LHCb and Belle-II experiments in the future.

   hep-phPRD(2024)·1 citation
8. 08*

   Entanglement Entropy Distributions of a Muon Decay

   Shanmuka Shivashankara🇺🇸 · Patti Rizzo🇺🇸 · Nicole Cafe🇺🇸

   Divergences that occur in density matrices of decay and scattering processes are shown to be regularized by tracing and unitarity or the optical theorem. These divergences are regularized by the lifetime of the decaying particle or the total scattering cross section. Also, this regularization is shown to give the expected helicities of final particles. The density matrix is derived for the weak decay of a polarized muon at rest, ${\mu }^{-}\to {\nu }_{\mu }(e^{-}{\bar{\nu }}_e)$, with Lorentz invariant density matrix entries and unitarity upheld at tree level. The electron's von Neumann entanglement entropy distributions are calculated with respect to both the electron's emission angle and energy. The angular entropy distribution favors an electron emitted backwards with respect to the muon's polarization given a minimum volume regularization. The kinematic entropy distribution is maximal at half the muon's rest mass energy. These results are similar to the electron's angular and kinematic decay rate distributions. Both the density matrix and entanglement entropy can be cast either in terms of ratios of areas or volumes.

   hep-phhep-thquant-phLHEP(2024)·4 citations
9. 09*

   A complex singlet extension of the Standard Model with a singlet fermion dark matter

   Gi-Chol Cho🇯🇵 · Chikako Idegawa🇯🇵 · Rie Inumiya🇯🇵

   We examine a complex singlet scalar extension of the Standard Model (CxSM) with an extra singlet fermion. Both the singlet scalar and fermion are dark matter (DM) candidates. It is known that although the scalar potential in the CxSM can realize strong first-order electroweak phase transition, the scalar DM included in the model gives only a tiny amount of the relic density compared to the observed one. Therefore, a fermion DM is introduced to compensate for the lack of relic density. We find that the scattering of the fermion DM and nucleons is sufficiently suppressed when the masses of scalar mediators are degenerate, as well as in the case of the scalar DM. We show the range of a combination of the mass and the Yukawa coupling of the fermion DM, which satisfies both the observed relic density and conditions of strong first-order electroweak phase transition.

   hep-phNPB(2024)·8 citations
10. 10*

    Predicting Quadrupole deformation via anisotropic flow and transverse momentum spectra in isotopic $\text{prescript}128-13554\mathrm{Xe}$ collisions at LHC

    Saraswati Pandey🇮🇳 · B. K. Singh🇮🇳

    In the hydrodynamical description of heavy-ion collisions, the elliptic flow ${\mathrm{v}}_2$ and triangular flow ${\mathrm{v}}_3$ are sensitive to the quadrupole deformation ${\beta }_2$ of the colliding nuclei. We produce ${\mathrm{v}}_2$ and ${\mathrm{v}}_3$ ratios qualitatively and quantitatively in most-central Xe-Xe collisions at 5.44 TeV. By employing HYDJET++ model, we study the sensitivity of anisotropic flow coefficients and mean transverse momentum to the quadrupole deformation and system-size in isotopic Xe-Xe collisions. Flow observables strongly depend on the strength of nucleon-nucleon scattering occuring in even-A and odd-A nuclei. Flow for odd-A nuclei is suppressed in comparison to flow in even-A collisions. There exists a linear inter-dependence between ${\mathrm{p}}_{\mathrm{T}}$ integrated anisotropic flow and nuclear deformation. Mean transverse momentum signifies the fireball temperature in body-body and tip-tip collisions. There exists a negative linear correlation of $⟨{\mathrm{p}}_{\mathrm{T}}⟩$ with collision system-size and a positive correlation with nuclear deformation. Flow measurements in high-energy, heavy-ion collisions using isotopic collision systems, offer a new precision tool to study nuclear structure physics. Observation of nuclear structure properties like nuclear deformation in a heavy-ion collision such as this would be very interesting.

    hep-phnucl-thEPJC(2024)·0 citations
11. 11*

    Critical dynamics within the real-time fRG approach

    Yong-rui Chen🇨🇳 · Yang-yang Tan🇨🇳 · Wei-jie Fu🇨🇳

    The Schwinger-Keldysh functional renormalization group (fRG) developed in [1] is employed to investigate critical dynamics related to a second-order phase transition. The effective action of model A is expanded to the order of $O({\partial }^2)$ in the derivative expansion for the $O(N)$ symmetry. By solving the fixed-point equations of effective potential and wave function, we obtain static and dynamic critical exponents for different values of the spatial dimension $d$ and the field component number $N$. It is found that one has $z\ge 2$ in the whole range of $2\le d\le 4$ for the case of $N=1$, while in the case of $N=4$ the dynamic critical exponent turns to $z<2$ when the dimension approach towards $d=2$.

    hep-phnucl-thPRD(2024)·9 citations
12. 12*

    An atomic probe of dark matter differential interactions with elementary particles

    Yossi Rosenzweig (1)🇮🇱 · Yevgeny Kats (1)🇮🇱 · Menachem Givon (1)🇮🇱 · Yonathan Japha (1)🇮🇱 · Ron Folman (1) ((1) Department of Physics, Ben-Gurion University of the Negev, Israel)🇮🇱

    Searching for physics beyond the Standard Model is one of the main tasks of experimental physics. Candidates for dark matter include axion-like ultralight bosonic particles. Comagnetometers form ultra-high sensitivity probes for such particles and any exotic field that interacts with the spin of an atom. Here, we propose a multi-atom-species probe that enables not only to discover such fields and measure their spectrum but also to determine the ratios of their coupling strengths to sub-atomic elementary particles, electrons, neutrons and protons. We further show that the multi-faceted capabilities of this probe may be demonstrated with synthetic exotic fields generated by a combination of regular magnetic fields and light-induced fictitious magnetic fields in alkali atoms. These synthetic fields also enable the accurate calibration of any magnetometer or comagnetometer probe for exotic physics.

    hep-phquant-phPRD(2024)·7 citations
13. 13*

    An Effective Field Theory study of medium heavy quark evolution

    Miguel Ángel Escobedo🇪🇸

    The evolution of hard probes in a medium is a complex multiscale problem that significantly benefits from the use of Effective Field Theories (EFTs). Within the EFT framework, we aim to define a series of EFTs in a way that addresses each energy scale individually in separate steps. However, studying hard probes in a medium presents challenges. This is because an EFT is typically constructed by formulating the most general Lagrangian compatible with the problem's symmetries. Nevertheless, medium effects may not always be encoded adequately in an effective action. In this paper, we construct an EFT that is valid for studying the evolution of a heavy quark in a QCD plasma containing few other heavy quarks, where degrees of freedom with an energy of the order of the temperature scale are integrated out. Through this example, we explicitly demonstrate how to handle the doubling of degrees that arise in non-equilibrium field theory. As a result, we derive a Fokker-Planck equation using only symmetry and power counting arguments. The methods introduced in this paper will pave the way for future developments in the study of quarkonium suppression.

    hep-phnucl-thUniverse(2024)·0 citations
14. 14*

    Polarization dynamics from moment equations

    Nora Weickgenannt🇫🇷 · Jean-Paul Blaizot🇫🇷

    We derive an expression for the local transverse polarization of a boost-invariant expanding system of massive particles, which involves a set of dynamical spin moments. Starting from spin kinetic theory, we obtain a closed set of equations of motion for these spin moments. These equations are valid during the full evolution of the system, from free streaming to local equilibrium, and can be used to study polarization phenomena in relativistic heavy-ion collisions.

    hep-phPRD(2024)·13 citations
15. 15*

    Revisiting the time-ordering issue of TMD soft factors: causality, coordinate space analyticity and new equalities

    Yizhuang Liu🇵🇱

    We show that as a result of causality-constrained coordinate space analyticity, the Drell-Yan-shape transverse-momentum dependent soft factor in the exponential regulator allows Euclidean-type parametric representations without cuts, to all orders in perturbation theory. Moreover, it is identical to another soft factor defined with a single time-ordering that has a natural interpretation as a space-like form factor. Furthermore, this relation continues to hold for a larger class of TMD soft factors that interpolate between three different rapidity regulators: the off-light-cone regulator, the finite light-front length regulator, and the exponential regulator.

    hep-phhep-thJHEP(2024)·2 citations
16. 16*

    Probing the Interactions of Axion-Like Particles with Electroweak Bosons and the Higgs Boson in the High Energy Regime at LHC

    Tisa Biswas🇮🇳

    We study the interactions of Axion-Like Particles (ALPs) with the Standard Model particles, aiming to probe their phenomenology via non-resonant searches at the LHC. These interactions are mediated by higher dimensional effective operators within two possible frameworks of linearly and non-linearly realised electroweak symmetry breaking. We consider the ALPs to be light enough to be produced on-shell and exploit their derivative couplings with the SM Higgs boson and the gauge bosons. We will use the high momentum transfer processes, namely $hZ,Z\gamma ,WW$ and $WW\gamma$ production from $pp$ collisions. We derive upper limits on the gauge-invariant interactions of ALPs with the electroweak bosons and/or Higgs boson that contribute to these processes, from the re-interpretation of the latest Run 2 available LHC data. The constraints we obtain are strong for ALP masses below 100 GeV. These allowed effective interactions in the ALP parameter space yield better significance at HL-LHC and thus, offer promising avenues for subsequent studies. Furthermore, we augment our cut-based analysis with gradient-boosted decision trees, which improve the statistical significance distinctly across these interaction channels. We briefly compare the results with the complementary probe of these couplings via direct production of ALPs in association with the Higgs boson or a vector boson.

    hep-phJHEP(2024)·19 citations
17. 17*

    Extending Global Fits of 4D Composite Higgs Models with Partially Composite Leptons

    Ethan Carragher🇬🇧 · Kenn Shern Goh🇦🇺 · Wei Su🇨🇳 · Martin White🇦🇺 · Anthony G. Williams🇦🇺

    We perform the first convergent Bayesian global fits of 4D Composite Higgs Models with partially-composite third generation quarks and leptons based on the minimal $SO(5)\to SO(4)$ symmetry breaking pattern. We consider two models with the $\tau$ lepton and its associated neutrino in different representations of $SO(5)$. Fitting each model with a wide array of experimental constraints allows us to analyse the Bayesian evidence and currently-observed fine-tuning of each model by calculating the Kullback-Leibler divergence between their respective priors and posteriors. Notably both models are found to be capable of satisfying all constraints simultaneously at the $3\sigma$ level at scales of $<5$ TeV. From a Bayesian viewpoint of naturalness the model with leptons in the $14$ and $10$ representations is preferred over those in the $5$ representation due to its lower fine-tuning. Finally, we consider the experimental signatures for the preferred parameters in these models, including lepton partner decay signatures and gluon-fusion produced Higgs signal strengths, and discuss their potential phenomenology at future high-luminosity LHC runs.

    hep-phJHEP(2024)·3 citations
18. 18*

    Sensitivity floor for primordial black holes with neutrino searches

    Qishan Liu🇨🇳 · Kenny C. Y. Ng🇨🇳

    Primordial black holes~(PBHs) formed in the early Universe are well-motivated dark matter~(DM) candidates over a wide range of masses. These PBHs could emit detectable signals in the form of photons, electrons, and neutrinos through Hawking radiation. We consider the null observations of astrophysical ${\bar{\nu }}_e$ flux from several neutrino detectors and set new constraints on the PBHs as the dominant DM component to be above $6.4\times 10^{15}\mathrm{g}$. We also estimate the expected constraints with JUNO for the prospects in the near future. Lastly, we note that the diffuse supernova neutrino background~(DSNB) is an unavoidable isotropic background. We thus estimate the sensitivity floor for PBH parameter space due to the DSNB and show that it is challenging for neutrino detectors to identify PBHs as they constitute 100\% of the DM above a mass of 9$\times 10^{15}$g.

    hep-phastro-ph.COastro-ph.HEPRD(2024)·10 citations
19. 19*

    Purely leptonic decays of heavy-flavored charged mesons

    Kalpalata Dash🇮🇳 · P. C. Dash🇮🇳 · R. N. Panda🇮🇳 · Susmita Kar🇮🇳 · N. Barik🇮🇳

    We study the purely leptonic decays of heavy-flavored charged pseudoscalar (P) and vector (V) mesons ($D_{(s)}^{(\ast )+}$, $B_{(c)}^{(\ast )+}$) in the relativistic independent quark (RIQ) model based on an average flavor-independent confining potential in equally mixed scalar-vector harmonic form. We first compute the mass spectra of the ground-state-mesons and fix the model parameters necessary for the present analysis. Using the meson wave functions derivable in the RIQ model, and model parameters so fixed from hadron spectroscopy, we predict the decay constants: $f_{P(V)}$, ratios of decay constants: $f_V/f_P$, $f_{P_1}/f_{P_2}$, $f_{V_1}/f_{V_2}$, and the branching fractions (BFs): $\mathcal{B}(P(V)\to l^{+}{\nu }_l)$, $l=e,\mu ,\tau$, which agree with the available experimental data and other Standard Model (SM) predictions. For the unmeasured decay constants especially in the purely leptonic decays of the charged vector mesons, our predictions could be tested in the upcoming Belle-II, SCTF, CEPC, FCC-ee and LHCb experiments in near future.

    hep-phPRD(2024)·8 citations
20. 20*

    Improving the performance of weak supervision searches using transfer and meta-learning

    Hugues Beauchesne🇹🇼 · Zong-En Chen🇹🇼 · Cheng-Wei Chiang🇹🇼

    Weak supervision searches have in principle the advantages of both being able to train on experimental data and being able to learn distinctive signal properties. However, the practical applicability of such searches is limited by the fact that successfully training a neural network via weak supervision can require a large amount of signal. In this work, we seek to create neural networks that can learn from less experimental signal by using transfer and meta-learning. The general idea is to first train a neural network on simulations, thereby learning concepts that can be reused or becoming a more efficient learner. The neural network would then be trained on experimental data and should require less signal because of its previous training. We find that transfer and meta-learning can substantially improve the performance of weak supervision searches.

    hep-phcs.LGhep-exJHEP(2024)·19 citations
21. 21*

    Shower formation constraints on cubic Lorentz Invariance Violation parameters in quantum electrodynamics

    Petr Satunin🇷🇺 · Andrey Sharofeev🇷🇺

    We present shower formation constraints on the Lorentz Invariance Violation (LIV) energy scale for photons with cubic dispersion relation from recent gamma ray observations in $100$ TeV -- PeV energy range by LHAASO observatory. We assume Myers-Pospelov effective field theory framework, and calculate the suppression for the Bethe-Heitler process which is mainly responsible for the formation of photon-initiated atmosphere showers. Comparing the high-energy photon events with the suppressed flux predictions we obtain $95\%$ CL constraints on the LIV energy scale. The obtained shower constraint $E_{\mathrm{LIV}}\gtrsim \mathcal{O}\left(10^{20}\text{mbox}GeV\right)$ is significantly weaker than existing birefringence constraints but is independent.

    hep-phastro-ph.HEEPJC(2024)·6 citations
22. 22*

    The future muon collider for the research of the anomalous neutral quartic $Z\gamma \gamma \gamma$, $ZZ\gamma \gamma$, and $ZZZ\gamma$ couplings

    A. Gutiérrez-Rodríguez🇲🇽 · V. Cetinkaya🇹🇷 · M. Köksal🇹🇷 · E. Gurkanli🇹🇷 · V. Ari🇹🇷 · M. A. Hernández-Ruíz🇲🇽

    In the post-LHC era, the muon collider represents a frontier project capable of providing high-energy and high-luminosity leptonic collisions among future lepton-lepton particle accelerators. In addition, it provides significantly cleaner final states than those produced in hadron collisions. With this expectation in mind, in this article, we research the sensitivity of the anomalous neutral gauge boson couplings $Z\gamma \gamma \gamma$, $ZZ\gamma \gamma$, and $ZZZ\gamma$ defined by dimension-8 operators, through the ${\mu }^{+}{\mu }^{-}\to {\mu }^{+}{\mu }^{-}Z\gamma$ signal, with the $Z$-boson decaying to a neutrino pair. The projections at the future muon collider with a center-of-mass energy of $\sqrt{s}=10$ TeV, integrated luminosity of $\mathcal{L}=10$ $\mathrm{a}{\mathrm{b}}^{-1}$, and systematic uncertainties of ${\delta }_{sys}=0\%,3\%,5\%$, give an expected sensitivity on the anomalous $f_{T,j}/{\Lambda }^4$ couplings at $95\%$ confidence level of the order of $\mathcal{O}(10^{-3}-10^{-1})$ $\mathrm{Te}{\mathrm{V}}^{-4}$. Compared with the research of the ATLAS and CMS Collaborations on the anomalous quartic gauge couplings, we find that the high-luminosity future muon collider could have better sensitivity.

    hep-phEur.Phys.J.Plus(2025)·6 citations
23. 23*

    Leptogenesis with dynamical couplings

    Peisi Huang🇺🇸 · Tao Xu🇺🇸

    We propose a novel leptogenesis mechanism with a temperature-dependent coupling between the right-handed neutrino and Standard Model particles. This coupling experiences suppression at high temperatures and becomes sizable when the lepton asymmetry washout processes are Boltzmann-suppressed. Such a feature ensures that the washout rates remain consistently below the Hubble expansion rate, preserving all lepton asymmetry generated in the decay of right-handed neutrinos. We illustrate the feasibility of this mechanism with two example models and show that the observed baryon asymmetry of the Universe can be successfully obtained for right-handed neutrino masses larger than $10^9\mathrm{GeV}$ as well as for smaller violation of charge-parity symmetry.

    hep-phPRD(2024)·3 citations
24. 24*

    On the dependence of the Landau gauge ghost-gluon-vertex on the number of flavors

    Fabian Zierler🇬🇧 · Reinhard Alkofer🇦🇹

    The gauge-boson, ghost and fermion propagators as well as the gauge-boson--ghost vertex function are studied for SU(N), Sp(2N) and SO(N) gauge groups. We solve a set of coupled Dyson-Schwinger equations in Landau gauge for a variable, fractional number $N_f$ of massless fermions in the fundamental representation. For large $N_f$ we find a phase transition from a chirally broken into a chirally symmetric phase that is consistent with the behavior expected inside the conformal window. Even in the presence of fermions the gauge-boson--ghost-vertex dressing remains small. In the conformal window this vertex shows the expected power law behavior. It does not assume its tree-level value in the far infrared, but the respective dressing function is a constant greater than one.

    hep-phhep-lathep-thPRD(2024)·5 citations
25. 25*

    The Anatomy of $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ Distributions

    Martin Gorbahn🇬🇧 · Ulserik Moldanazarova🇬🇧 · Kai Henryk Sieja🇩🇪 · Emmanuel Stamou🇩🇪 · Mustafa Tabet🇩🇪

    The excellent experimental prospects to measure the invisible mass spectrum of the $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ decay opens a new path to test generalised quark--neutrino interactions with flavour changing $s\to d$ transitions and as such to novel probes of Physics beyond the Standard Model. Such signals can be a consequence of new lepton-number violating or lepton-number conserving interactions, with their interpretations depending on the Majorana versus Dirac nature of the neutrinos. Furthermore, the possible existence of new massive sterile neutrinos can be tested via their distinctive imprints in the invariant mass spectrum. Within the model-independent framework of the weak effective theory at dimension-six, we study the New Physics effects of Majorana and Dirac neutrinos on the differential distribution of $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ allowing for lepton-number violating interactions and potential new sterile neutrinos. We determine the current and expected future sensitivity on the corresponding $\Delta S=1$ neutral-current Wilson coefficients using the distribution measured by the NA62 collaboration and accounting for expected improvements based on the HIKE experiment. We present single-operator fits and also determine correlations among different type of operators. Even though we focus on $s\to d\nu \nu$ transitions, the operator bases for Majorana and Dirac and the classification of lepton-number-violating/conserving interactions is applicable also for the study of $b\to s/d\nu \nu$ and $c\to u\nu \nu$ transitions relevant in current phenomenology.

    hep-phEPJC(2024)·21 citations
26. 26*

    N${}^3$LL resummation of one-jettiness for $Z$-boson plus jet production at hadron colliders

    Simone Alioli🇮🇹 · Guido Bell🇩🇪 · Georgios Billis🇮🇹 · Alessandro Broggio🇦🇹 · Bahman Dehnadi🇩🇪 · Matthew A. Lim🇬🇧 · Giulia Marinelli🇮🇹 · Riccardo Nagar🇮🇹 · Davide Napoletano🇮🇹 · Rudi Rahn🇬🇧

    We present the resummation of one-jettiness for the colour-singlet plus jet production process $pp\to ({\gamma }^{\ast }/Z\to {\ell }^{+}{\ell }^{-})+\text{jet}$ at hadron colliders up to the fourth logarithmic order (N${}^3$LL). This is the first resummation at this order for processes involving three coloured partons at the Born level. We match our resummation formula to the corresponding fixed-order predictions, extending the validity of our results to regions of the phase space where further hard emissions are present. This result paves the way for the construction of next-to-next-to-leading order simulations for colour-singlet plus jet production matched to parton showers in the GENEVA framework.

    hep-phhep-exPRD(2024)·18 citations
27. 27*

    Exploring hidden sectors with two-particle angular correlations at future $e^{+}{e}^{-}$ colliders

    E. Musumeci (1)🇪🇸 · A. Irles (1)🇪🇸 · R. Perez-Ramos (2,3)🇫🇷 · I. Corredoira (4)🇪🇸 · E. Sarkisyan-Grinbaum (5,6)🇨🇭 · V. A. Mitsou (1,7)🇪🇸 · M. A. Sanchis-Lozano (1) ((1) Instituto de Física Corpuscular, CSIC - University of Valencia, Paterna (Valencia), Spain, (2) DRII-IPSA, Ivry-sur-Seine, France, (3) Laboratoire de Physique Th éorique et Hautes Energies (LPTHE), Sorbonne Université et CNRS, Paris Cedex, France, (4) Instituto Galego de Física de Altas Enerxìas (IGFAE, USC), Spain, (5) Experimental Physics Department, CERN, Geneva, Switzerland, (6) Department of Physics, The University of Texas at Arlington, Arlington, TX, USA, (7) Physics Division, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Athens, Greece)🇪🇸

    Future $e^{+}{e}^{-}$ colliders are expected to play a fundamental role in measuring Standard Model (SM) parameters with unprecedented precision and in probing physics beyond the SM (BSM). This study investigates two-particle angular correlation distributions involving final-state SM charged hadrons. Unexpected correlation structures in these distributions is considered to be a hint for new physics perturbing the QCD partonic cascade and thereby modifying azimuthal and (pseudo)rapidity correlations. Using Pythia8 Monte Carlo generator and fast simulation, including selection cuts and detector effects, we study potential structures in the two-particle angular correlation function. We adopt the QCD-like Hidden Valley (HV) scenario as implemented in Pythia8 generator, with relatively light HV $v$-quarks (below about 100 GeV), to illustrate the potential of this method.

    hep-phhep-exMDPI Physics(2025)·7 citations
28. 28*

    The simplicial substructure of jets

    Tejes Gaertner🇬🇧 · Jared Reiten🇺🇸

    In this work, we construct a new data type for hadronic jets in which the traditional point-cloud representation is transformed into a simplicial complex consisting of vertices, or 0-simplexes. An angular resolution scale, $r$, is then drawn about each vertex, forming balls about hadrons. As $r$ grows, the overlap of balls form 2- and 3-point connections, thereby appending 1- and 2-simplexes to the complex. We thus associate a jet with an angular-resolution-dependent characterization of its substructure -- we dub this data type the simplicial substructure complex $K_{\mathrm{sub}}(r)$. This data type gives rise to two interesting representations. First, the subset of 0-and 1-simplexes lends itself naturally to a graph representation of a given jet's substructure and we provide examples of valuable graph-theoretic calculations such a representation affords. Second, the subset of 1- and 2-simplexes gives rise to what is known as a Face-Counting-Vector, in topological combinatorics parlance. We explore information-theoretic aspects of the components of this vector, various metric properties which follow, as well as how this vector can be used to define new jet-shape observables. The utility of these representations is demonstrated in the context of the discrimination of jets initiated by light quarks and gluons from those initiated by tops.

    hep-ph2 citations
29. 29*

    Constraints on photon mass and dark photon from the Jovian magnetic field

    Shi Yan🇺🇸 · Lingfeng Li🇺🇸 · JiJi Fan🇺🇸

    The Jovian magnetic field, being the strongest and largest planetary one in the solar system, could offer us new insights into possible microscopic scale new physics, such as a non-zero mass of the Standard Model (SM) photon or a light dark photon kinetically mixing with the SM photon. We employ the immense data set from the latest Juno mission, which provides us unprecedented information about the magnetic field of the gas giant, together with a more rigorous statistical approach compared to the literature, to set strong constraints on the dark photon mass and kinetic mixing parameter, as well as the SM photon mass. The constraint on the dark photon parameters is independent of whether dark photon is (part of) dark matter or not, and serves as the most stringent one in a certain regime of the parameter space.

    hep-phastro-ph.EPphysics.space-phJHEP(2024)·19 citations
30. 30*

    Electroweak Phase Transition with a Double Well Done Doubly Well

    Prateek Agrawal🇬🇧 · Simone Blasi🇩🇪 · Alberto Mariotti🇧🇪 · Michael Nee🇬🇧

    We revisit the electroweak phase transition in the scalar singlet extension of the standard model with a ${\mathbb{Z}}_2$ symmetry. In significant parts of the parameter space the phase transition occurs in two steps - including canonical benchmarks used in experimental projections for gravitational waves. Domain walls produced in the first step of the transition seed the final step to the electroweak vacuum, an effect which is typically neglected but leads to an exponentially enhanced tunnelling rate. We improve previous results obtained for the seeded transition, which made use of the thin-wall or high temperature approximations, by using the mountain pass algorithm that was recently proposed as a useful tool for seeded processes. We then determine the predictions of the seeded transition for the latent heat, bubble size and characteristic time scale of the transition. Differences compared to homogeneous transitions are most pronounced when there are relatively few domain walls per hubble patch, potentially leading to an enhanced gravitational wave signal. We also provide a derivation of the percolation criteria for a generic seeded transition, which applies to the domain wall seeds we consider as well as to strings and monopoles.

    hep-phastro-ph.COJHEP(2024)·35 citations
31. 31*

    Search for Dark Matter Ionization on the Night Side of Jupiter with Cassini

    Carlos Blanco🇺🇸 · Rebecca K. Leane🇺🇸

    We present a new search for dark matter using planetary atmospheres. We point out that annihilating dark matter in planets can produce ionizing radiation, which can lead to excess production of ionospheric $H_3^{+}$. We apply this search strategy to the night side of Jupiter near the equator. The night side has zero solar irradiation, and low latitudes are sufficiently far from ionizing auroras, leading to an effectively background-free search. We use Cassini data on ionospheric $H_3^{+}$ emission collected 3 hours either side of Jovian midnight, during its flyby in 2000, and set novel constraints on the dark matter-nucleon scattering cross section down to about $10^{-38}$ cm${}^2$. We also highlight that dark matter atmospheric ionization may be detected in Jovian exoplanets using future high-precision measurements of planetary spectra.

    hep-phastro-ph.EPastro-ph.HEPRL(2024)·23 citations
32. 32*

    Superradiant Leptogenesis

    Anish Ghoshal🇵🇱 · Yuber F. Perez-Gonzalez🇬🇧 · Jessica Turner🇬🇧

    We investigate how superradiance affects the generation of baryon asymmetry in a universe with rotating primordial black holes, considering a scenario where a scalar boson is coupled to the heavy right-handed neutrinos. We identify the regions of the parameter space where the scalar production is enhanced due to superradiance. This enhancement, coupled with the subsequent decay of the scalar into right handed neutrinos, results in the non-thermal creation of lepton asymmetry. We show that successful leptogenesis is achieved for masses of primordial black holes in the range of order $O(0.1\mathrm{g})-O(10\mathrm{g})$ and the lightest of the heavy neutrino masses, $M_N\sim O(10^{12})\mathrm{GeV}$. Consequently, regions of the parameter space, which in the case of Schwarzchild PBHs were incompatible with viable leptogenesis, can produce the observed matter-antimatter asymmetry.

    hep-phastro-ph.COJHEP(2024)·22 citations
33. 33*

    Box integrals with fermion bubbles for low-energy measurements of the weak mixing angle

    Nico Böttcher🇩🇪 · Niklas Schwanemann🇩🇪 · Stefan Weinzierl🇩🇪

    The Moller experiment and the P2 experiment aim at measuring the weak mixing angle at low scales. The Moller experiment uses $e^{-}{e}^{-}\to e^{-}{e}^{-}$-scattering, the P2 experiment uses $e^{-}N\to e^{-}N$-scattering. In both cases, two-loop electroweak corrections have to be taken into account, and here in particular diagrams which give rise to large logarithms. In this paper we compute a set of two-loop electroweak Feynman integrals for point-like particles, which are obtained from a box integral by the insertion of a light fermion loop. By rationalising all occurring square roots we show that these Feynman integrals can be expressed in terms of multiple polylogarithms. We present the results in a form, which makes the large logarithms manifest. We provide highly efficient numerical evaluation routines for these integrals.

    hep-phEPJC(2024)·3 citations
34. 34*

    Light Dirac neutrino portal dark matter with gauged $U(1{)}_{B-L}$ symmetry

    Nayan Das🇮🇳 · Debasish Borah🇮🇳

    We propose a gauged $U(1{)}_{B-L}$ version of the light Dirac neutrino portal dark matter. The $U(1{)}_{B-L}$ symmetry provides a UV completion by naturally accommodating three right handed neutrinos from anomaly cancellation requirements which, in combination with the left handed neutrinos, form the sub-eV Dirac neutrinos after electroweak symmetry breaking. The particle content and the gauge charges are chosen in such a way that light neutrinos remain purely Dirac and dark matter, a gauge singlet Dirac fermion, remain stable. We consider both thermal and non-thermal production possibilities of dark matter and correlate the corresponding parameter space with the one within reach of future cosmic microwave background (CMB) experiments sensitive to enhanced relativistic degrees of freedom $\Delta N_{\mathrm{eff}}$. The interplay of dark matter, CMB, structure formation and other terrestrial constraints keep the scenario very predictive leading the $U(1{)}_{B-L}$ parameter space into tight corners.

    hep-phastro-ph.COPRD(2024)·8 citations
35. 35*

    Collisions and collective flavor conversion: Integrating out the fast dynamics

    Damiano F. G. Fiorillo🇩🇰 · Ian Padilla-Gay🇺🇸 · Georg G. Raffelt🇩🇪

    In dense astrophysical environments, notably core-collapse supernovae and neutron star mergers, neutrino-neutrino forward scattering can spawn flavor conversion on very short scales. Scattering with the background medium can impact collective flavor conversion in various ways, either damping oscillations or possibly setting off novel collisional flavor instabilities (CFIs). A key feature in this process is the slowness of collisions compared to the much faster dynamics of neutrino-neutrino refraction. Assuming spatial homogeneity, we leverage this hierarchy of scales to simplify the description accounting only for the slow dynamics driven by collisions. We illustrate our new approach both in the case of CFIs and in the case of fast instabilities damped by collisions. In both cases, our strategy provides new equations, the slow-dynamics equations, that simplify the description of flavor conversion and allow us to qualitatively understand the final state of the system after the instability, either collisional or fast, has saturated.

    hep-phastro-ph.COastro-ph.HEPRD(2024)·32 citations
36. 36*

    Quantum Algorithms for Simulating Nuclear Effective Field Theories

    James D. Watson🇺🇸 · Jacob Bringewatt🇺🇸 · Alexander F. Shaw🇺🇸 · Andrew M. Childs🇺🇸 · Alexey V. Gorshkov🇺🇸 · Zohreh Davoudi🇺🇸

    Quantum computers offer the potential to simulate nuclear processes that are classically intractable. With the goal of understanding the necessary quantum resources to realize this potential, we employ state-of-the-art Hamiltonian-simulation methods, and conduct a thorough algorithmic analysis, to estimate the qubit and gate costs to simulate low-energy effective field theories (EFTs) of nuclear physics. Within the framework of nuclear lattice EFT, we obtain simulation costs for the leading-order pionless and pionful EFTs. For the latter, we consider both static pions represented by a one-pion-exchange potential between the nucleons, and dynamical pions represented by relativistic bosonic fields coupled to non-relativistic nucleons. Within these models, we examine the resource costs for the tasks of time evolution and energy estimation for physically relevant scales. We account for model errors associated with truncating either long-range interactions in the one-pion-exchange EFT or the pionic Hilbert space in the dynamical-pion EFT, and for algorithmic errors associated with product-formula approximations and quantum phase estimation. We find that the pionless EFT is the least costly to simulate, followed by the one-pion-exchange theory, then the dynamical-pion theory. We demonstrate how symmetries of the low-energy nuclear Hamiltonians can be utilized to obtain tighter error bounds. By retaining the locality of nucleonic interactions when mapped to qubits, we achieve reduced circuit depth and substantial parallelization. In the process, we develop new methods to bound the algorithmic error for classes of fermionic number-preserving Hamiltonians, and obtain tighter Trotter error bounds by explicitly computing nested commutators of Hamiltonian terms. Compared to previous estimates for the pionless EFT, our results represent an improvement by several orders of magnitude.

    ↳ quant-phhep-lathep-phnucl-th40 citations
37. 37*

    Axion limits from the 10-year gamma-ray emission 1ES 1215+303

    Hai-Jun Li🇨🇳 · Wei Chao🇨🇳 · Yu-Feng Zhou🇨🇳

    We present the limits on photon to axionlike particle (ALP) coupling from the 10-year period observations of the TeV BL Lacertae blazar 1ES 1215+303 (with redshift $z=0.130$). The contemporaneous gamma-ray spectra are measured by the collaborations Fermi-LAT and VERITAS with five flux phases from 2008 to 2017, including four low states and one flare. Using these flux phases, we show the spectral energy distributions (SEDs) under the null/ALP hypotheses and set the combined limit on ALP. The 95% $C.L.$ combined limit set by 1ES 1215+303 with the 10-year gamma-ray data is roughly at the photon-ALP coupling constant $g_{a\gamma }\gtrsim 1.5\times 10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ for the ALP mass $5.0\times 10^{-10}\mathrm{eV}\lesssim m_a\lesssim 1.0\times 10^{-7}\mathrm{eV}$.

    ↳ astro-ph.HEhep-phPLB(2024)·6 citations
38. 38*

    Numerical 1-loop correction from a potential yielding ultra-slow-roll dynamics

    Matthew W. Davies🇬🇧 · Laura Iacconi🇬🇧 · David J. Mulryne🇬🇧

    Single-field models of inflation might lead to amplified scalar fluctuations on small scales due, for example, to a transient ultra-slow-roll phase. It was argued by Kristiano $\&$ Yokoyama in arXiv:2211.03395 that the enhanced amplitude of the scalar power spectrum on small scales has the potential to induce a sizeable 1-loop correction to the spectrum at large scales. In this work, we repeat the calculation for the 1-loop correction presented in arXiv:2211.03395. We closely follow their assumptions but evaluate the loop numerically. This allows us to consider both instantaneous and smooth transitions between the slow-roll and ultra-slow-roll phases. In particular, we generate models featuring realistic, smooth evolution from an analytic inflationary potential. We find that, upon fixing the amplitude of the peak in the power spectrum at short scales, the resulting 1-loop correction is not significantly reduced by considering a smooth evolution. In particular, for a power spectrum with a tree-level peak amplitude potentially relevant for small-scale phenomenology, e.g. primordial black hole production, the 1-loop correction on large scales is a few percent of the tree-level power spectrum.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2024)·53 citations
39. 39*

    Anomalous dimensions of twist-two operators in extended N=2 and N=4 super Yang-Mills theories

    B.A. Kniehl🇩🇪 · V.N. Velizhanin🇩🇪

    We perform direct diagrammatic calculations of the anomalous dimensions of twist-two operators in extended N=2 and N=4 super Yang-Mills theories (SYM). In the case of N=4 SYM, we compute the four-loop anomalous dimension of the twist-two operator for several fixed values of Lorentz spin. This is the first direct diagrammatic calculation of this kind, and we confirm results previously obtained by means of integrability. For N=2 SYM, we obtain the general result for the anomalous dimension at third order of perturbation theory and find the three-loop Cusp anomalous dimension.

    ↳ hep-thhep-phNPB(2024)·7 citations
40. 40*

    Black Hole Perturbation Theory Meets CFT${}_2$: Kerr Compton Amplitudes from Nekrasov-Shatashvili Functions

    Yilber Fabian Bautista🇫🇷 · Giulio Bonelli🇮🇹 · Cristoforo Iossa🇨🇭 · Alessandro Tanzini🇮🇹 · Zihan Zhou🇺🇸

    We present a novel study of Kerr Compton amplitudes in a partial wave basis in terms of the Nekrasov-Shatashvili (NS) function of the confluent Heun equation (CHE). Remarkably, NS-functions enjoy analytic properties and symmetries that are naturally inherited by the Compton amplitudes. Based on this, we characterize the analytic dependence of the Compton phase-shift in the Kerr spin parameter and provide a direct comparison to the standard post-Minkowskian (PM) perturbative approach within General Relativity (GR). We also analyze the universal large frequency behavior of the relevant characteristic exponent of the CHE -- also known as the renormalized angular momentum -- and find agreement with numerical computations. Moreover, we discuss the analytic continuation in the harmonics quantum number $\ell$ of the partial wave, and show that the limit to the physical integer values commutes with the PM expansion of the observables. Finally, we obtain the contributions to the tree level, point-particle, gravitational Compton amplitude in a covariant basis through $O(a_{\text{BH}}^8)$, without the need to take the super-extremal limit for Kerr spin.

    ↳ hep-thgr-qchep-phPRD(2024)·108 citations
41. 41*

    Rotating gluon system and confinement

    Yin Jiang🇨🇳

    In this work the non-abelian gauge theory is reformulated in a local inertial frame with the presence of a background rotation. With this new formalism the influence of the background rotation on the color deconfinement transition for a SU(2) pure gluon system. The KvBLL caloron, which is a color neutral and asymptotically nontrivial solution of Yang-Mills equation at finite temperature, is adopted to confine the color charges. With new solutions of the caloron's constituent particles, i.e. dyons, the semi-classical potential, which confines color charges, and the perturbative potential, induced by the Gaussian fluctuation, have been obtained for this system under rotation. By solving the critical temperature of confinement-deconfinement phase transition in different computation schemes, it is found that neither the rotational semi-classical potential nor Gaussian fluctuations can confine color charges more tightly when the rotation becomes faster. While only a stronger coupling constant is able to make the critical temperature increasing with angular velocity, as that indicated in lattice simulations. And it is also found with some particular sets of parameters, a non-monotonic dependence of the critical temperature will be obtained in the most physically realistic case, in which all the three factors are taken into account.

    ↳ hep-thhep-phnucl-thPLB(2024)·23 citations
42. 42*

    Expansion of hypergeometric functions in terms of polylogarithms with nontrivial variable change

    M.A. Bezuglov🇷🇺 · A.I. Onishchenko🇷🇺

    Hypergeometric functions of one and many variables play an important role in various branches of modern physics and mathematics. Often we have hypergeometric functions with indices linear dependent on a small parameter with respect to which one needs to perform Laurent expansions. Moreover such expansions are desirable to be expressed in terms of well known functions which can be evaluated with arbitrary precision. To solve this problem we use the differential equation method and the reduction of corresponding differential systems to canonical basis. Specifically we will be interested in the generalized hypergeometric functions of one variable together with Appell and Lauricella functions and their expansions in terms of Goncharov polylogarithms. Particular attention will be given to the case of rational indices of considered hypergeometric functions when the reduction to canonical basis involves nontrivial variable change. The article comes with a Mathematica package Diogenes, which provides algorithmic implementation of the required steps.

    ↳ hep-thhep-phmath-phmath.MPTheor.Math.Phys.(2024)·9 citations
43. 43*

    Effect of hadronic interaction on the flow of $K^{\ast 0}$

    Tribhuban Parida🇮🇳 · Sandeep Chatterjee🇮🇳 · Md. Nasim🇮🇳

    We explore the implications of the late stage hadronic rescattering phase on the flow of $K^{\ast 0}$. The model calculations are done using a (3+1)-dimensional hybrid framework, incorporating both hydrodynamic evolution and hadronic transport that is calibrated to agree with bulk observables including the elusive rapidity differential $v_1$ of light-flavor hadrons. We find that the late stage hadronic rescattering phase causes significant qualitative modification of the $K^{\ast 0}$ $v_1$ resulting in $\frac{d{v}_1}{dy}(K^{\ast 0})-\frac{d{v}_1}{dy}(K^{+})$ and $\frac{d{v}_1}{dy}(\varphi )-\frac{d{v}_1}{dy}(K^{+})$ to have opposite signs with the effect being more pronounced in central collisions as compared to peripheral ones due to the larger multiplicity as well as longer duration of the hadronic phase. Further, this effect is enhanced in low-energy collisions owing to a stronger breaking of boost invariance. On the contrary, the influence of the hadronic phase on the $K^{\ast 0}$ elliptic flow $v_2$ is found to be less significant and quantitative.

    ↳ nucl-thhep-phnucl-exPRC(2024)·7 citations
44. 44*

    Constraints on initial baryon stopping and equation of state from directed flow

    Lipei Du🇨🇦 · Chun Shen🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    Our investigation focuses on the rapidity-dependent directed flow, $v_1(y)$, of identified hadrons in Au+Au collisions across a broad range of $\sqrt{s_{\mathrm{NN}}}$ from 7.7 to 200 GeV. Employing a (3+1)-dimensional hybrid framework, our study successfully reproduces the characteristic features of the measured $v_1(y)$ for both mesons and baryons across the considered beam energies. Notably, our analysis reveals the constraining power of baryonic $v_1(y)$ on the initial baryon stopping mechanism. Together with mesonic $v_1(y)$, the directed flow serves as a crucial tool for probing the equation of state governing dense nuclear matter at finite chemical potentials.

    ↳ nucl-thhep-exhep-phnucl-exEPJ Web Conf.(2024)·2 citations
45. 45*

    Energy Dependence of Flavor Instabilities Stemming from Crossings in the Neutrino Flavor Lepton Number Angular Distribution

    Pedro Dedin Neto🇧🇷 · Irene Tamborra🇩🇰 · Shashank Shalgar🇩🇰

    In core-collapse supernovae and neutron star mergers, the neutrino density is so large that neutrino-neutrino refraction can lead to flavor conversion, if a zero-crossing is present in the neutrino flavor lepton number (FLN) angular distribution and the neutrino self-interaction strength $\mu =\sqrt{2}{G}_F{n}_{\nu }$ represents the characteristic timescale of the system. It has been empirically realized that the vacuum frequency $\omega =\Delta m^2/2E$ affects the development of flavor conversion in the presence of zero-crossing even if $\omega \ll \mu$. Focusing on a homogeneous and axially symmetric neutrino gas, we explore the role of $\omega$ in the onset of flavor instabilities. We find that a non-zero vacuum frequency can be responsible for inducing flavor instabilities even when the neutrino self-interaction strength is much larger than the vacuum frequency. Moreover, mapping a neutrino ensemble with $\omega \ne 0$ into an effective system with $\omega =0$, we find that a system with no FLN zero-crossing can effectively develop one for $\omega \ne 0$ becoming unstable.

    ↳ astro-ph.HEhep-ph12 citations
46. 46*

    On Amplitudes and Field Redefinitions

    Timothy Cohen🇨🇭 · Xiaochuan Lu🇺🇸 · Dave Sutherland🇬🇧

    We derive an off-shell recursion relation for correlators that holds at all loop orders. This allows us to prove how generalized amplitudes transform under generic field redefinitions, starting from an assumed behavior of the one-particle-irreducible effective action. The form of the recursion relation resembles the operation of raising the rank of a tensor by acting with a covariant derivative. This inspires a geometric interpretation, whose features and flaws we investigate.

    ↳ hep-thhep-phJHEP(2024)·31 citations
47. 47*

    Astronomical Image Blurring from Transversely Correlated Quantum Gravity Fluctuations

    Vincent S. H. Lee🇺🇸 · Kathryn M. Zurek🇺🇸 · Yanbei Chen🇺🇸

    Quantum fluctuations in spacetime can, in some cases, lead to distortion in astronomical images of faraway objects. In particular, a stochastic model of quantum gravity predicts an accumulated fluctuation in the path length $\Delta L$ with variance $⟨\Delta L^2⟩\sim l_{p}L$ over a distance $L$, similar to a random walk, and assuming no spatial correlation above length $l_p$; it has been argued that such an effect is ruled out by observation of sharp images from distant stars. However, in other theories, such as the pixellon (modeled on the Verlinde-Zurek (VZ) effect), quantum fluctuations can still accumulate as in the random walk model while simultaneously having large distance correlations in the fluctuations. Using renormalization by analytic continuation, we derive the correlation transverse to the light propagation, and show that image distortion effects in the pixellon model are strongly suppressed in comparison to the random walk model, thus evading all existing and future constraints. We also find that the diffraction of light rays does not lead to qualitative changes in the blurring effect.

    ↳ gr-qcastro-ph.HEhep-phPRD(2024)·14 citations
48. 48*

    Cosmological Correlators in massless ${\varphi }^4$-theory and the Method of Regions

    Martin Beneke🇩🇪 · Patrick Hager🇩🇪 · Andrea F. Sanfilippo🇩🇪

    The calculation of loop corrections to the correlation functions of quantum fields during inflation or in the de~Sitter background presents greater challenges than in flat space due to the more complicated form of the mode functions. While in flat space highly sophisticated approaches to Feynman integrals exist, similar tools still remain to be developed for cosmological correlators. However, usually only their late-time limit is of interest. We introduce the method-of-region expansion for cosmological correlators as a tool to extract the late-time limit, and illustrate it with several examples for the interacting, massless, minimally coupled scalar field in de~Sitter space. In particular, we consider the in-in correlator $⟨{\varphi }^2(\eta ,q)\varphi (\eta ,k_1)\varphi (\eta ,k_2)⟩$, whose region structure is relevant to anomalous dimensions and matching coefficients in Soft de Sitter effective theory.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2024)·40 citations
49. 49*

    Mach's principle and dark matter

    Joao Magueijo🇬🇧

    In this paper we entertain a Machian setting where local physics is non-locally affected by the whole Universe, taking the liberty to identify the local (``Newton's bucket'') with our visible Universe, and the whole Universe (Mach's ``fixed stars'') with the global Universe beyond our horizon. Crucially, we allow for the two to have different properties, so that we are beyond the traditional FRW setting. For definiteness we focus on theories where non-locality arises from evolution in the laws of physics in terms of spatially global time variables dual to the constants of Nature. Since non-local theories are foliation-dependent, the {\it local} (but not the global) Hamiltonian constraint is lost. This is true not only while non-locality is taking place, but also after it ceases: the local Hamiltonian constraint is only recovered up to a constant in time, keeping a memory of the integrated past non-locality. We show that this integration constant is equivalent to preserving the local Hamiltonian constraint and adding an extra fluid with the same cosmological properties as conventional pressureless dark matter. The equivalence breaks down in terms of clustering properties, with the new component attracting other matter, but not budging from its location. This is the ultimate ``painted-on'' dark matter, attracting but not being attracted, and nailing down a preferred frame.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2024)·7 citations
50. 50*

    Dynamically massive linear covariant gauges: setup and first results

    Giorgio Comitini🇮🇹 · Tim De Meerleer🇧🇪 · David Dudal🇧🇪 · Silvio Paolo Sorella🇧🇷

    We discuss the possibility to obtain a massive Landau gauge, based on the local composite operator (LCO) effective action framework combined with the Zimmerman reduction of couplings prescription. As a way to deal with the gauge ambiguity, we check that the ghost propagator remains positive, a necessary condition for gluon field configurations beyond the Gribov region to be negligible. We pay attention to the BRST invariance of the construction, allowing for a future generalization to a class of massive linear covariant gauges. As a litmus test, we compare our predictions to the lattice data for the two-point functions in Landau gauge introducing the "Dynamically Infrared-Safe" renormalization scheme, including the renormalization group optimization of both the gap equation and the two-point functions. We also discuss the relation to and differences with the Curci-Ferrari model, the usefulness of which in providing an effective perturbative description of non-perturbative Yang-Mills theories became clear during recent years.

    ↳ hep-thhep-phPRD(2024)·7 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.