Wed·Mar 1, 2023Wednesday·March 1, 2023

1. 01*

   The remarkable role of the vector-like quark doublet in the Cabibbo angle and $W$-mass anomalies

   Benedetta Belfatto🇮🇹 · Sokratis Trifinopoulos🇺🇸

   The combination of precise determinations of $V_{us}$ and $V_{ud}$ hints towards a violation of the CKM first row unitarity at about $3\sigma$ level. Conversely, the recent measurement of the $W$-boson mass by the CDF Collaboration exhibits significant tension with the SM prediction, intensifying the conflict that may arise in models addressing the unitarity violation. We demonstrate that one vector-like $SU(2{)}_L$ doublet with mass of a few TeV mixing with light quarks and the top quark can simultaneously account for the two anomalies, without conflicting with flavour-changing phenomena and electroweak observables. Moreover, another tension in the value of the Cabibbo angle is reported also at $3\sigma$ level, between two determinations of $V_{us}$ obtained from semi-leptonic $K\ell 3$ and leptonic $K\mu 2$ kaon decays. We show that the vector-like doublet can be at the origin of this discrepancy and the substantial positive shift in the $W$-boson mass. This unique feature of the vector-like quark doublet may render it a crucial puzzle piece in new physics scenarios addressing the CKM unitarity problem. The model can be potentially probed in future colliders.

   hep-phPRD(2023)·30 citations
2. 02*

   $1/N_c$ Nambu -- Jona-Lasinio model: Electrically charged and strange pseudoscalars

   A. A. Osipov🇷🇺

   The mass formulas and decay constants of electrically charged and strange pseudoscalar mesons are analyzed within the combined framework of Nambu -- Jona-Lasinio model and the $1/N_c$ expansion up to $\mathcal{O}(1/N_c^2)$. The light quark masses explicitly violating $SU(3{)}_L\times SU(3{)}_R$ chiral symmetry of the strong interactions are taken to be of order $\mathcal{O}(1/N_c)$. The Fock-Schwinger proper-time method and the Volterra series are used to derive the effective action. A set of sum rules is obtained that relates the phenomenological values of the masses of pseudoscalar mesons to the mass ratios of light quarks. It is shown that combining the new sum rules with the experimental data on the decay width $\eta \to 3\pi$ allows to establish limits for the ratios: $0.47<m_u/m_d<0.59$ and $18.60<m_s/m_d<19.66$. A comparison with the results of similar calculations in $1/N_c$ chiral perturbation theory is made.

   hep-phPRD(2023)·10 citations
3. 03*

   Effective Field Theory of Chirally-Enhanced Muon Mass and Dipole Operators

   Radovan Dermisek🇺🇸 · Keith Hermanek🇺🇸 · Navin McGinnis🇨🇦 · Sangsik Yoon🇺🇸

   We study corrections to observables related to the muon in the context of models of new physics which generate mass-enhanced corrections to the muon dipole moments. Working in the Standard Model effective theory, we demonstrate a correlation between the decay of the Higgs boson to muons, and the magnetic and electric dipole moments of the muon generated by the dominant matching corrections. This defines a novel way to classify predictions for a wide variety of models of new physics based on the pattern of deviations of these three observables. In particular, when applied to specific models we find that this correlation has a potential to rule out whole models or set upper bounds on the scale of new physics motivated by the muon anomalous magnetic moment.

   hep-phPRD(2023)·12 citations
4. 04*

   Quantifying the tension between cosmological and terrestrial constraints on neutrino masses

   Stefano Gariazzo🇮🇹 · Olga Mena🇪🇸 · Thomas Schwetz🇩🇪

   The sensitivity of cosmology to the total neutrino mass scale $\Sigma m_{\nu }$ is approaching the minimal values required by oscillation data. We study quantitatively possible tensions between current and forecasted cosmological and terrestrial neutrino mass limits by applying suitable statistical tests such as Bayesian suspiciousness, parameter goodness-of-fit tests, or a parameter difference test. In particular, the tension will depend on whether the normal or the inverted neutrino mass ordering is assumed. We argue, that it makes sense to reject inverted ordering from the cosmology/oscillation comparison only if data are consistent with normal ordering. Our results indicate that, in order to reject inverted ordering with this argument, an accuracy on the sum of neutrino masses $\sigma (m_{\nu })$ of better than 0.02~eV would be required from future cosmological observations.

   hep-phastro-ph.COPhys.Dark Univ.(2023)·31 citations
5. 05*

   Spontaneous Lorentz symmetry breaking effects on GRBs jets arising from neutrino pair annihilation process near a black hole

   Mohsen Khodadi🇮🇷 · Gaetano Lambiase🇮🇹 · Leonardo Mastrototaro🇮🇹

   The study of neutrino pair annihilation into electron-positron pairs ($\nu \bar{\nu }\to e^{-}{e}^{+}$) is astrophysically well-motivated because it is a possible powering mechanism for the gamma-ray bursts (GRBs). In this paper, we estimate the gamma-ray energy deposition rate (EDR) arising from the annihilation of the neutrino pairs in the equatorial plane of a slowly rotating black hole geometry modified by the broken Lorentz symmetry (induced by a background bumblebee vector field). More specifically, owing to the presence of a dimensionless Lorentz symmetry breaking (LSB) parameter $l$ arising from nonminimal coupling between the bumblebee field with nonzero vacuum expectation value and gravity, the metric solution in question differs from the standard slowly rotating Kerr black hole. By idealizing the thin accretion disk temperature profile in the two forms of isothermal and gradient around the bumblebee gravity-based slow rotating black hole, we investigate the influence of spontaneous LSB on the $\nu \bar{\nu }$-annihilation efficiency. For both profiles, we find that positive values of LSB parameter $l>0$ induce an enhancement of the EDR associated with the neutrino-antineutrino annihilation. Therefore, the process of powering the GRBs jets around bumblebee gravity modified slowly rotating geometry is more efficient in comparison with standard metric. Using the observed gamma-ray luminosity associated with different GRBs types (short, long, and ultra-long), we find, through the analysis of the EDR in the parameter space $l-a$ ($a^2\ll 1$), some allowed ranges for the LSB parameter $l$.

   hep-phastro-ph.HEgr-qcEPJC(2023)·36 citations
6. 06*

   Model for the propagation of fermions in a Bose-Einstein condensate

   José F. Nieves🇺🇸 · Sarira Sahu🇲🇽

   We consider the dispersion relations of fermions that propagate in the background of a scalar Bose-Einstein condensate. Some illustrative examples are discussed using simple Yukawa-type coupling models between the fermions and the scalar fields. The dispersion relations are determined explicitly in those cases, to the lowest order. The method also allows to determine the corrections to the dispersion relations due to the interactions with the excitations of the Bose-Einstein condensate. Possible applications of the results to the case of neutrinos are indicated.

   hep-phastro-ph.HEPRD(2023)·4 citations
7. 07*

   Mission Target: Exotic Multiquark Hadrons -- Sharpened Blades

   Wolfgang Lucha🇦🇹

   Motivated by recent experimental progress in establishing the likely existence of (variants of) exotic hadrons, predicted to be formed by the strong interactions, various proposed concepts and ideas are compiled in an attempt to draft a coherent picture of the achievable improvement in the theoretical interpretation of exotic hadrons in terms of the underlying quantum field theory of strong interactions.

   hep-phhep-thnucl-thUniverse(2023)·2 citations
8. 08*

   Open Strange Mesons in (magnetized) nuclear matter

   Ankit Kumar🇮🇳 · Amruta Mishra🇮🇳

   We investigate the mass modifications of open strange mesons (vector $K^{\ast }$ and axial vector $K_1$) in (magnetized) isospin asymmetric nuclear matter using quantum chromodynamics sum rule (QCDSR) approach. The in-medium decay widths of $K^{\ast }$ $\to$ $K\pi$ and $K_1$ $\to$ $K^{\ast }\pi$ are studied from the mass modifications of $K_1$, $K^{\ast }$ and $K$ mesons, using a light quark-antiquark pair creation model, namely the ${}^3{P}_0$ model. The in-medium decay width for $K_1$ $\to$ $K^{\ast }\pi$ is compared with the decay widths calculated using a phenomenological Lagrangian. The effects of magnetic fields are also studied on the mass and the partial decay width of the vector $K^{\ast }$ meson decaying to $K\pi$. Within the QCD sum rule approach, the medium effects on the masses of the open strange mesons are calculated from the light quark condensates and the gluon condensates in the hadronic medium. The quark condensates are calculated from the medium modifications of the scalar fields ($\sigma$, $\zeta$, and $\delta$) in the mean field approximation within a chiral $SU(3)$ model, while the scalar gluon condensate is obtained from the medium modification of a scalar dilaton field ($\chi$), which is introduced within the model to imitate the scale invariance breaking of QCD.

   hep-ph2 citations
9. 09*

   Listening to dark sirens from gravitational waves:\it{Combined effects of fifth force, ultralight particle radiation, and eccentricity}

   Tanmay Kumar Poddar🇮🇳 · Anish Ghoshal🇵🇱 · Gaetano Lambiase🇮🇹

   We derive in detail the orbital period loss of a compact binary system in presence of a fifth force and radiation of ultralight particles for a general eccentric Keplerian orbit. We obtain constraints on fifth force strength $\alpha \lesssim 1.11\times 10^{-3}$ from the orbital period decay of compact binary systems. We derive constraints on the gauge coupling of ultralight scalar $(g_S\lesssim 3.06\times 10^{-20})$ and vector $(g_V\lesssim 2.29\times 10^{-20})$ particles from orbital period loss and the constraints get stronger in presence of a fifth force $(\alpha =0.9)$. In addition, we also obtain constraints on the axion decay constant $(7.94\times 10^{10}\mathrm{GeV}\lesssim {\mathrm{f}}_{\mathrm{a}}\lesssim 3.16\times 10^{17}\mathrm{GeV},\alpha =0.9)$ if the orbital period decays due to the combined effects of axionic fifth force and axion radiation. We also achieve constraints on the strengths of the fifth force $(\alpha \lesssim 0.025)$ and radiation $(\beta \lesssim 10^{-3})$ from GW170817. The constraints on new force parameters depend on the choice of the initial eccentricity which we include in our analysis $({ϵ}_0=10^{-6},0.1)$. We do the model independent estimate of the capture of dark matter mass fraction by a binary system. Lastly, we obtain constraints on fifth force strength due to Brans-Dicke mediated scalar between two compact stars in a binary system $({\omega }_{\mathrm{BD}}>266)$ and from the Nordtvedt effect $({\omega }_{\mathrm{BD}}>75858)$. The bound on Brans-Dicke coupling gets stronger if one includes the effect of eccentricity. Our constraints can be generalized to any alternative theories of gravity and will be within the reach of second and third generation gravitational wave detectors.

   hep-phastro-ph.COgr-qcPhys.Dark Univ.(2024)·14 citations
10. 10*

    Neutrinoless double beta decay in Left-Right symmetric model with double seesaw mechanism

    Sudhanwa Patra🇮🇳 · S. T. Petcov🇮🇹 · Prativa Pritimita🇮🇳 · Purushottam Sahu🇮🇳

    We discuss a left-right (L-R) symmetric model with the double seesaw mechanism at the TeV scale generating Majorana masses for the active left-handed (LH) flavour neutrinos ${\nu }_{\alpha L}$ and the heavy right-handed (RH) neutrinos $N_{\beta R}$, $\alpha ,\beta =e,\mu ,\tau$, which in turn mediate lepton number violating processes, including neutrinoless double beta decay. The Higgs sector is composed of two Higgs doublets $H_L$, $H_R$, and a bi-doublet $\Phi$. The fermion sector has the usual for the L-R symmetric models quarks and leptons, along with three $SU(2)$ singlet fermion $S_{\gamma L}$. The choice of bare Majorana mass term for these sterile fermions induces large Majorana masses for the heavy RH neutrinos leading to two sets of heavy Majorana particles $N_j$ and $S_k$, $j,k=1,2,3$, with masses $m_{N_j}\ll m_{S_k}$. Working with a specific version of the model in which the ${\nu }_{\alpha L}-N_{\beta R}$ and the $N_{\beta R}-S_{\gamma L}$ Dirac mass terms are diagonal, and assuming that $m_{N_j}\sim (1-1000)$ GeV and $\max (m_{S_k})\sim (1-10)$ TeV, $m_{N_j}\ll m_{S_k}$, we study in detail the new ``non-standard'' contributions to the $0\nu \beta \beta$ decay amplitude and half-life arising due to the exchange of virtual $N_j$ and $S_k$. We find that in both cases of NO and IO light neutrino mass spectra, these contributions are strongly enhanced and are dominant at relatively small values of the lightest neutrino mass $m_{1(3)}\sim (10^{-4}-10^{-2})$ eV over the light Majorana neutrino exchange contribution. In large part of the parameter space, the predictions of the model for the $0\nu \beta \beta$ decay generalised effective Majorana mass and half-life are within the sensitivity range of the planned next generation of neutrinoless double beta decay experiments LEGEND-200 (LEGEND-1000), nEXO, KamlAND-Zen-II, CUPID, NEXT-HD.

    hep-phPRD(2023)·19 citations
11. 11*

    Status of the lifetimes of heavy hadrons within the HQE

    Maria Laura Piscopo🇩🇪

    We present the theoretical status of the lifetimes of weakly decaying heavy hadrons containing a bottom or a charm quark, and discuss the current predictions, based on the framework of the Heavy Quark Expansion (HQE), for both mesons and baryons. Potential improvements to reduce the theoretical uncertainties are also highlighted.

    hep-phhep-exPoS(2024)·4 citations
12. 12*

    Search for the singlet vector-like top quark in the $T\to tZ$ channel with $Z\to \nu \bar{\nu }$ at hadron colliders

    Lin Han🇨🇳 · Shiyu Wang🇨🇳 · Liangliang Shang🇨🇳 · Bingfang Yang🇨🇳

    Based on a simplified model including a singlet vector-like top quark $T$ with charge $|Q|=2/3$, we analyze the prospects of observing $T$ via the single $T$ production in the $tZ$ channel with $Z$ decaying to neutrinos at the hadron-hadron colliders. This simplified model only includes two free parameters, the coupling constant $g^{\ast }$ and the $T$ quark mass $m_T$. To investigate the observability of the single $T$ production, we perform a detailed background analysis and detector simulation for the collision energies 14~TeV, 27~TeV, and 100~TeV. We scan the $g^{\ast }-m_T$ parameter space and show the exclusion and discovery capabilities on the $T$ quark with the highest integrated luminosity designed at these colliders. Moreover, the limits from the narrow-width approximation and electroweak precision observables are considered.

    hep-phCPC(2023)·6 citations
13. 13*

    Zero Casimir Force in Axion Electrodynamics and the Search for a New Force

    Yohei Ema🇺🇸 · Masashi Hazumi🇯🇵 · Hideo Iizuka🇯🇵 · Kyohei Mukaida🇯🇵 · Kazunori Nakayama🇯🇵

    We point out that there is a stable configuration of metal plates where the Casimir force is vanishing in axion electrodynamics. We consider a concrete setup involving Weyl semimetals, which hosts an axion-like effect on the electromagnetism, towards the measurement of the axionic effect on the Casimir force. Our setup realizes zero Casimir force between metals and may be useful for the search for new force mediated by light particles at the micrometer scale.

    hep-phcond-mat.mes-hallhep-exquant-phPRD(2023)·12 citations
14. 14*

    Light Shining Through a Thin Wall: Evanescent Hidden Photon Detection

    Asher Berlin🇺🇸 · Roni Harnik🇺🇸 · Ryan Janish🇺🇸

    A kinetically-mixed hidden photon is sourced as an evanescent mode by electromagnetic fields that oscillate at a frequency smaller than the hidden photon mass. These evanescent modes fall off exponentially with distance, but nevertheless yield detectable signals in a photon regeneration experiment if the electromagnetic barrier is made sufficiently thin. We consider such an experiment using superconducting cavities at GHz frequencies, proposing various cavity and mode arrangements that enable unique sensitivity to hidden photon masses ranging from $10^{-5}$ eV to $10^{-1}$ eV.

    hep-phhep-ex2 citations
15. 15*

    DAEMONFLUX: DAta-drivEn MuOn-calibrated atmospheric Neutrino Flux

    Juan Pablo Yañez🇨🇦 · Anatoli Fedynitch🇹🇼

    In this paper, we present a refined calculation of the atmospheric neutrino flux spanning from GeV to PeV energies. Our method, Daemonflux, utilizes data-driven inputs and incorporates adjustable parameters to take their uncertainties into account. By optimizing these parameters using a combination of muon data and constraints from fixed-target experiments, we achieve uncertainties in the calculated neutrino fluxes of less than 10% up to 1 TeV, with neutrino ratios constrained to below 10%. Our model performs particularly well at energies below 100 GeV, where the smallest errors are obtained. We make our model available as a software package that provides access to predictions of fluxes, ratios, and errors, including the covariance matrix obtained from the fit.

    hep-phastro-ph.HEPRD(2023)·58 citations
16. 16*

    $H_0=69.8\pm 1.3$ $\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, ${\Omega }_{m0}=0.288\pm 0.017$, and other constraints from lower-redshift, non-CMB, expansion-rate data

    Shulei Cao🇺🇸 · Bharat Ratra🇺🇸

    We use updated Type Ia Pantheon+ supernova, baryon acoustic oscillation, and Hubble parameter (now also accounting for correlations) data, as well as new reverberation-measured C IV quasar data, and quasar angular size, H II starburst galaxy, reverberation-measured Mg II quasar, and Amati-correlated gamma-ray burst data to constrain cosmological parameters. We show that these data sets result in mutually consistent constraints and jointly use them to constrain cosmological parameters in six different spatially-flat and non-flat cosmological models. Our analysis provides summary model-independent determinations of two key cosmological parameters: the Hubble constant, $H_0=69.8\pm 1.3$ $\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, and the current non-relativistic matter density parameter, ${\Omega }_{m0}=0.288\pm 0.017$. Our summary error bars are 2.4 and 2.3 times those obtained using the flat $\Lambda$CDM model and Planck TT,TE,EE+lowE+lensing cosmic microwave background (CMB) anisotropy data. Our $H_0$ value is very consistent with that from the local expansion rate based on the Tip of the Red Giant Branch data, is 2$\sigma$ lower than that from the local expansion rate based on Type Ia supernova and Cepheid data, and is 2$\sigma$ higher than that in the flat $\Lambda$CDM model based on Planck TT,TE,EE+lowE+lensing CMB data. Our data compilation shows at most mild evidence for non-flat spatial hypersurfaces, but more significant evidence for dark energy dynamics, 2$\sigma$ or larger in the spatially-flat dynamical dark energy models we study.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·77 citations
17. 17*

    Ntuple Wizard: An Application to Access Large-Scale Open Data from LHCb

    Christine A. Aidala🇺🇸 · Christopher Burr🇨🇭 · Marco Cattaneo🇨🇭 · Dillon S. Fitzgerald🇺🇸 · Adam Morris🇨🇭 · Sebastian Neubert🇩🇪 · Donijor Tropmann🇨🇭

    Making the large data sets collected at the Large Hadron Collider (LHC) accessible to the world is a considerable challenge because of both the complexity and the volume of data. This paper presents the Ntuple Wizard, an application that leverages the existing computing infrastructure available to the LHCb collaboration in order to enable third-party users to request specific data. An intuitive web interface allows the discovery of accessible data sets and guides the user through the process of specifying a configuration-based request. The application allows for fine-grained control of the level of access granted to the public.

    ↳ hep-exhep-phComput.Softw.Big Sci.(2023)·6 citations
18. 18*

    Complex Langevin Method on Rotating Matrix Quantum Mechanics at Thermal Equilibrium

    Takehiro Azuma🇯🇵 · Takeshi Morita🇯🇵 · Hiroki Yoshida🇯🇵

    Rotating systems in thermal equilibrium are ubiquitous in our world. In the context of high energy physics, rotations would affect the phase structure of QCD. However, the standard Monte-Carlo methods in rotating systems are problematic because the chemical potentials for the angular momenta (angular velocities) cause sign problems even for bosonic variables. In this article, we demonstrate that the complex Langevin method (CLM) may overcome this issue. We apply the CLM to the Yang-Mills (YM) type one-dimensional matrix model (matrix quantum mechanics) that is a large-$N$ reduction (or dimensional reduction) of the $(D+1)$-dimensional U$(N)$ pure YM theory (bosonic BFSS model). This model shows a large-$N$ phase transition at finite temperature, which is analogous to the confinement/deconfinement transition of the original YM theory, and our CLM predicts that the transition temperature decreases as the angular momentum chemical potential increases. In order to verify our results, we compute several quantities via the minimum sensitivity method and find good quantitative agreements. Hence, the CLM properly works in this rotating system. We also argue that our results are qualitatively consistent with a holography and the recent studies of the imaginary angular velocity in QCD. As a byproduct, we develop an analytic approximation to treat the so-called ``small black hole" phase in the matrix model.

    ↳ hep-thcond-mat.quant-gashep-lathep-phPTEP(2023)·3 citations
19. 19*

    Effects of $N(2080){3/2}^{-}$ and $N(2270)3/2^{-}$ molecules on $K^{\ast }\Sigma$ photoproduction

    Di Ben🇨🇳 · Ai-Chao Wang🇨🇳 · Fei Huang🇨🇳 · Bing-Song Zou🇨🇳

    In the present work, we re-analyze the available data for $\gamma p\to K^{\ast +}{\Sigma }^0$ and $\gamma p\to K^{\ast 0}{\Sigma }^{+}$ by considering the contributions from the $N(2080){3/2}^{-}$ and $N(2270)3/2^{-}$ molecules instead of any nucleon resonances in the $s$ channel, where the $N(2080)3/2^{-}$ was proposed to be a $K^{\ast }\Sigma$ molecule as the strange partner of the $P_c^{+}(4457)$ hadronic molecular state, and the $N(2270)3/2^{-}$ was assumed to be a $K^{\ast }{\Sigma }^{\ast }$ molecule as the strange partner of the ${\bar{D}}^{\ast }{\Sigma }_c^{\ast }$ bound states that are predicated as members in the same heavy-quark spin symmetry multiplet as the $P_c$ states. It turns out that all the available cross-section data can be well reproduced, indicating that the molecular structures of the possible $N(2080){3/2}^{-}$ and $N(2270)3/2^{-}$ states are compatible with the available data for $K^{\ast }\Sigma$ photoproduction reactions. Further analysis shows that for both $\gamma p\to K^{\ast +}{\Sigma }^0$ and $\gamma p\to K^{\ast 0}{\Sigma }^{+}$ reactions, the $N(2080){3/2}^{-}$ exchange provides dominant contributions to the cross-sections in the near-threshold energy region, and significant contributions from the $N(2270)3/2^{-}$ exchange to the cross-sections in the higher energy region are also found. Predictions of the beam asymmetry $\Sigma$, target asymmetry $T$, and recoil baryon asymmetry $P$ are presented and compared with those from our previous work. Measurements of the data on these observables are called on to further constrain the reaction mechanisms of $K^{\ast }\Sigma$ photoproduction reactions and to verify the molecular scenario of the $N(2080){3/2}^{-}$ and $N(2270)3/2^{-}$ states.

    ↳ nucl-thhep-exhep-phPRC(2023)·17 citations
20. 20*

    Spatial Curvature from Super-Hubble Cosmological Fluctuations

    Baptiste Blachier🇧🇪 · Pierre Auclair🇧🇪 · Christophe Ringeval🇧🇪 · Vincent Vennin🇫🇷

    We revisit how super-Hubble cosmological fluctuations induce, at any time in the cosmic history, a non-vanishing spatial curvature of the local background metric. The random nature of these fluctuations promotes the curvature density parameter to a stochastic quantity for which we derive novel non-perturbative expressions for its mean, variance, higher moments and full probability distribution. For scale-invariant Gaussian perturbations, such as those favored by cosmological observations, we find that the most probable value for the curvature density parameter ${\Omega }_{\mathrm{K}}$ today is $-10^{-9}$, that its mean is $+10^{-9}$, both being overwhelmed by a standard deviation of order $10^{-5}$. We then discuss how these numbers would be affected by the presence of large super-Hubble non-Gaussianities, or, if inflation lasted for a very long time. In particular, we find that substantial values of ${\Omega }_{\mathrm{K}}$ are obtained if inflation lasts for more than a billion e-folds.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·11 citations
21. 21*

    Inverse Problems in PDF Determinations

    Alessandro Candido🇮🇹 · Luigi Del Debbio🇬🇧 · Tommaso Giani🇳🇱 · Giacomo Petrillo🇮🇹

    The determination of Parton Distribution Functions from a finite set of data is a typical example of an inverse problem. Inverse problems are notoriously difficult to solve, in particular when a robust determination of the uncertainty in the result is needed. We present a Bayesian framework to deal with this problem and discuss first results from a closure test.

    ↳ hep-lathep-phPoS(2023)·21 citations
22. 22*

    Renormalisation group flows connecting a $4-ϵ$ dimensional Hermitian field theory to a $\mathcal{P}\mathcal{T}$-symmetric theory for a fermion coupled to an axion

    Lewis Croney🇬🇧 · Sarben Sarkar🇬🇧

    The renormalisation group flow of a Hermitian field theory is shown to have trajectories which lead to a non-Hermitian Parity-Time ($\mathcal{P}\mathcal{T}$) symmetric field theory for an axion coupled to a fermion in spacetime dimensions $D=4-ϵ$, where $ϵ>0$. In this renormalisable field theory, the Dirac fermion field has a Yukawa coupling $g$ to a pseudoscalar (axion) field and there is quartic pseudoscalar self-coupling $u$. The robustness of this finding is established by considering flows between $ϵ$ dpependent Wilson-Fisher fixed points and also by working to \emph{three loops} in the Yukawa coupling and to \emph{two loops} in the quartic scalar coupling. The flows in the neighbourhood of the non-trivial fixed points are calculated using perturbative analysis, together with the $ϵ$ expansion. The global flow pattern indicates flows from positive $u$ to negative $u$; there are no flows between real and imaginary $g$. Using summation techniques we demonstrate a possible non-perturbative $\mathcal{P}\mathcal{T}$-symmetric saddle point for $D=3$.

    ↳ hep-thhep-phquant-phPRD(2023)·9 citations
23. 23*

    Loop-level double-copy for massive fermions in the fundamental

    John Joseph M. Carrasco🇺🇸 · Aslan Seifi🇺🇸

    We find that unitarity cuts and the duality between color and kinematics are sufficient constraints to bootstrap $D$-dimensional QCD scattering amplitudes starting from three-particle tree-level. Specifically, we calculate tree level amplitudes through six-points, as well as the four-point one-loop correction for massive fermions in the fundamental representation of the gauge group -- constructing a color-dual representation of the latter for the first time. To do so we clarify a prescription for functional kinematic ansatze involving fermionic matter. The advantages of color-dual calculation, familiar from particles in the adjoint, also apply here: only a small number of basis topologies must be constrained via physical information of the theory, and algebraic relations propagate this to a full solution. As all the QCD amplitudes we construct here are color-dual, they trivially generate $D$-dimensional amplitudes in gravitational theories via double-copy construction.

    ↳ hep-thhep-phJHEP(2023)·8 citations
24. 24*

    Categorical Symmetry of the Standard Model from Gravitational Anomaly

    Pavel Putrov🇮🇹 · Juven Wang🇺🇸

    In the Standard Model, some combination of the baryon $\mathbf{B}$ and lepton $\mathbf{L}$ number symmetry is free of mixed anomalies with strong and electroweak $su(3)\times su(2)\times u(1{)}_{\tilde{Y}}$ gauge forces. However, it can still suffer from a mixed gravitational anomaly, hypothetically pertinent to leptogenesis in the very early universe. This happens when the total "sterile right-handed" neutrino number $n_{{\nu }_R}$ is not equal to the family number $N_f$. Thus the invertible $\mathbf{B}-\mathbf{L}$ symmetry current conservation can be violated quantum mechanically by gravitational backgrounds such as gravitational instantons. In specific, we show that a noninvertible categorical $\mathbf{B}-\mathbf{L}$ generalized symmetry still survives in gravitational backgrounds. In general, we propose a construction of noninvertible symmetry charge operators as topological defects derived from invertible anomalous symmetries that suffer from mixed gravitational anomalies. Examples include the perturbative local and nonperturbative global anomalies classified by $\mathbb{Z}$ and ${\mathbb{Z}}_{16}$ respectively. For this construction, we utilize the anomaly inflow bulk-boundary correspondence, the 4d Pontryagin class and the gravitational Chern-Simons 3-form, the 3d Witten-Reshetikhin-Turaev-type topological quantum field theory corresponding to a 2d rational conformal field theory with an appropriate rational chiral central charge, and the 4d ${\mathbb{Z}}_4^{\mathrm{TF}}$-time-reversal symmetric topological superconductor with 3d boundary topological order.

    ↳ hep-thcond-mat.str-elgr-qchep-phPRD(2024)·68 citations
25. 25*

    What neutron stars tell about the hadron-quark phase transition: a Bayesian study

    János Takátsy🇭🇺 · Péter Kovács🇭🇺 · György Wolf🇭🇺 · Jürgen Schaffner-Bielich🇩🇪

    The existence of quark matter inside the heaviest neutron stars has been the topic of numerous recent studies, many of them suggesting that a phase transition to strongly interacting conformal matter inside neutron stars is feasible. Here we examine this hybrid star scenario using a soft and a stiff hadronic model, a constituent quark model with three quark flavours, and applying a smooth crossover transition between the two. Within a Bayesian framework, we study the effect of up-to-date constraints from neutron star observations on the equation-of-state parameters and various neutron star observables. Our results show that a pure quark core is only possible if the maximum mass of neutron stars is below $\sim 2.35M_{\odot }$. However, we also find, consistently with other studies, that a peak in the speed of sound, exceeding $1/3$, is highly favoured by astrophysical measurements, which might indicate the percolation of hadrons at $\sim 3-4n_0$. Even though our prediction for the phase transition parameters varies depending on the specific astrophysical constraints utilized, the position of the speed of sound peak only changes slightly, while the existence of pure quark matter below $\sim 4n_0$, using our parameterization, is disfavoured. On the other hand, the preferred range for the EoS shows signs of conformality above $\sim 4n_0$. Additionally, we present the difference in the upper bounds of radius estimates using the full probability density data and sharp cut-offs, and stress the necessity of using the former.

    ↳ astro-ph.HEhep-phnucl-thPRD(2023)·63 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.