Mon·Sep 13, 2021Monday·September 13, 2021

1. 01*

   The momentum broadening of energetic partons in an anisotropic plasma

   Sigtryggur Hauksson🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   The quark-gluon plasma produced in heavy-ion collisions is anisotropic throughout its evolution. This anisotropy changes the physics of jet-medium interaction, making it dependent on the momentum direction of the jet. In this paper we analyze transverse momentum broadening of a jet parton interacting with soft gluons in an anisotropic plasma. Our analysis equally applies to momentum broadening of quasiparticles in kinetic theory. We subtract contribution from instability modes in the deep infrared and discuss how our calculation should be complemented in that regime. The resulting anisotropic collision kernel for momentum broadening is qualitatively different from the equilibrium collision kernel and from the isotropic ansatz used in effective kinetic theory. Because of increased medium screening, there is substantially less transverse broadening at low and intermediate momenta.

   hep-phnucl-thPRC(2022)·50 citations
2. 02*

   Electrically charged supermassive twin stars

   V. P. Goncalves🇧🇷 · J. C. Jimenez🇧🇷 · L. Lazzari🇧🇷

   By assuming that ultra dense hybrid neutron stars are endowed with a distribution of electric charge, we study the corresponding twin star solutions and their properties resulting from a sharp first order transition from confined hadronic to a deconfined quark phase. Two distinct quark matter equations of state with increasing stiffness are considered and the values for the maximum gravitational masses of the hadronic and hybrid twin configurations are obtained for different values of the total electric charge. Interestingly, our calculations indicate that sharp transitions make charged twin hybrid stars more massive than their neutral counterparts, and that the {$\text{SI}2M_{\odot }$ constraint from PSR J0740+6620} is surpassed for standard values of electric charge and can be considered stable only satisfying $\partial M/\partial {ϵ}_0>0$. In particular, our charged stellar models reach masses even higher than the unknown compact object measured in the GW190814 event.

   hep-phastro-ph.HEEPJC(2022)·11 citations
3. 03*

   Inflation and dark matter after spontaneous Planck scale generation by hidden chiral symmetry breaking

   Mayumi Aoki🇯🇵 · Jisuke Kubo🇩🇪 · Jinbo Yang🇯🇵

   Dynamical chiral symmetry breaking in a QCD-like hidden sector is used to generate the Planck mass and the electroweak scale including the heavy right-handed neutrino mass. A real scalar field transmits the energy scale of the hidden sector to the visible sectors, playing besides a role of inflaton in the early Universe while realizing a Higgs-inflation-like model. Our dark matter candidates are hidden pions that raise due to dynamical chiral symmetry breaking. They are produced from the decay of inflaton. Unfortunately, it will be impossible to directly detect them, because they are super heavy ($10^{9\sim 12}$ GeV), and moreover the interaction with the visible sector is extremely suppressed.

   hep-phJCAP(2022)·16 citations
4. 04*

   Dark Photon bounds in the dark EFT

   Daniele Barducci🇮🇹 · Enrico Bertuzzo🇧🇷 · Giovanni Grilli di Cortona🇮🇹 · Gabriel M. Salla🇧🇷

   Dark photons are massive abelian gauge bosons that interact with ordinary photons via a kinetic mixing with the hypercharge field strength tensor. This theory is probed by a variety of different experiments and limits are set on a combination of the dark photon mass and kinetic mixing parameter. These limits can however be strongly modified by the presence of additional heavy degrees of freedom. Using the framework of dark effective field theory, we study how robust are the current experimental bounds when these new states are present. We focus in particular on the possible existence of a dark dipole interaction between the Standard Model leptons and the dark photon. We show that, under certain assumptions, the presence of a dark dipole modifies existing supernovæ bounds for cut-off scales up to $\mathcal{O}(10-100\text{TeV})$. On the other hand, terrestrial experiments, such as LSND and E137, can probe cut-off scales up to $\mathcal{O}(3\text{TeV})$. For the latter experiment we highlight that the bound may extend down to vanishing kinetic mixing.

   hep-phJHEP(2021)·28 citations
5. 05*

   Charge asymmetry in electron/positron energy loss in nuclear Bremsstrahlung

   Roman N. Lee🇷🇺 · Andrey F. Pikelner🇷🇺

   We calculate the leading Coulomb correction to the energy loss in the electron-nucleus Bremsstrahlung for arbitrary energy of the incoming particle. This correction determines the charge asymmetry, i.e., the difference of electron and positron energy loss. The result is presented in terms of the classical polylogarithms ${\mathrm{Li}}_2$ and ${\mathrm{Li}}_3$. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. We provide both the threshold and the high-energy asymptotics of the found asymmetry and compare them with the available results.

   hep-phJHEP(2021)·1 citation
6. 06*

   Using $B_s^0\to D_s^{\mp }{K}^{\pm }$ Decays as a Portal to New Physics

   Robert Fleischer🇳🇱 · Eleftheria Malami🇳🇱

   The system of $B_s^0\to D_s^{\mp }{K}^{\pm }$ decays offers a theoretically clean determination of the angle $\gamma$ of the Unitarity Triangle. A corresponding LHCb analysis resulted in a surprisingly large result, which is in tension with other determinations and global analyses of the Unitarity Triangle. Paying special attention to discrete ambiguities, we confirm this picture and resolve a final ambiguity. Moreover, we extract the branching ratios of the underlying ${\bar{B}}_s^0\to D_s^{+}{K}^{-}$ and ${\bar{B}}_s^0\to D_s^{-}{K}^{+}$ modes. Combining them with information from semileptonic $B_{(s)}$ decays, we arrive at another puzzling situation, which we obtain also for other decays with similar dynamics. These patterns could be footprints of New Physics in the $b\to c\bar{u}s$ and $b\to u\bar{c}s$ processes which govern the dynamics of the ${\bar{B}}_s^0\to D_s^{\mp }{K}^{\pm }$ channels. Employing a model-independent parametrisation, we present a strategy to reveal such effects. Applying it to the present data, we obtain strongly correlated New-Physics contributions with potentially large CP-violating phases. We find that new contributions sizeably smaller than the Standard Model amplitudes could actually accommodate the current data. This strategy offers an exciting probe for new sources of CP violation at the future high-precision frontier of $B$ physics.

   hep-phhep-exPRD(2022)·41 citations
7. 07*

   Toy models for hierarchy studies

   Clara Álvarez-Luna🇪🇸 · José A. R. Cembranos🇪🇸 · Juan José Sanz-Cillero🇪🇸

   We provide a simple computation in order to estimate the probability of a given hierarchy between two scales. In particular, we work in a model provided with a gauge symmetry, with two scalar doublets. We start from a scale-invariant classical Lagrangian, but by taking into account the Coleman-Weinberg mechanism, we obtain masses for the gauge bosons and the scalars. This approach typically provides a light (L) and a heavy (H) sector related to the two different vacuum expectation values of the two scalars. We compute the size of the hyper-volume of the parameter space of the model associated with an interval of mass ratios between these two sectors. We define the probability as proportional to this size and conclude that probabilities of very large hierarchies are not negligible in the type of models studied in this letter.

   hep-phEPJC(2022)·2 citations
8. 08*

   Dispersive analysis of glueball masses

   Hsiang-nan Li🇹🇼

   We develop an inverse matrix method to solve for resonance masses from a dispersion relation obeyed by a correlation function. Given the operator product expansion (OPE) of a correlation function in the deep Euclidean region, we obtain the nonperturbative spectral density, which exhibits resonance structures naturally. The value of the gluon condensate in the OPE is fixed by producing the $\rho$ meson mass in the formalism, and then input into the dispersion relations for the scalar, pseudoscalar and tensor glueballs. It is shown that the low-energy limit of the correlation function for the scalar glueball, derived from the spectral density, discriminates the lattice estimate for the triple-gluon condensate from the single-instanton estimate. The spectral densities for the scalar and pseudoscalar glueballs reveal a double-peak structure: the peak located at lower mass implies that the $f_0(500)$ and $f_0(980)$ ($\eta$ ad ${\eta }^{\prime }$) mesons contain small amount of gluonium components, and should be included into scalar (pseudoscalar) mixing frameworks. Another peak determines the scalar (pseudoscalar) glueball mass around 1.50 (1.75) GeV with a broad width about 200 MeV, suggesting that the $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ ($\eta (1760)$) mesons are the glue-rich states. We also predict the topological susceptability ${\chi }_t^{1/4}=75$-78 MeV, deduced from the correlation function for the pseudoscalar glueball at zero momentum. Our analysis gives no resonance solution for the tensor glueball, which may be attributed to the insufficient nonperturbative condensate information in the currently available OPE.

   hep-phPRD(2021)·28 citations
9. 09*

   Publishing statistical models: Getting the most out of particle physics experiments

   Kyle Cranmer🇺🇸 · Sabine Kraml🇫🇷 · Harrison B. Prosper (editors)🇺🇸 · Philip Bechtle🇩🇪 · Florian U. Bernlochner🇩🇪 · Itay M. Bloch🇮🇱 · Enzo Canonero🇮🇹 · Marcin Chrzaszcz🇵🇱 · Andrea Coccaro🇮🇹 · Jan Conrad🇸🇪 · Glen Cowan🇬🇧 · Matthew Feickert🇺🇸 and 21 other authors

   The statistical models used to derive the results of experimental analyses are of incredible scientific value and are essential information for analysis preservation and reuse. In this paper, we make the scientific case for systematically publishing the full statistical models and discuss the technical developments that make this practical. By means of a variety of physics cases -- including parton distribution functions, Higgs boson measurements, effective field theory interpretations, direct searches for new physics, heavy flavor physics, direct dark matter detection, world averages, and beyond the Standard Model global fits -- we illustrate how detailed information on the statistical modelling can enhance the short- and long-term impact of experimental results.

   hep-phhep-exSciPost Phys.(2022)·56 citations
10. 10*

    Space-time structure of 3+1D color fields in high energy nuclear collisions

    Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Soeren Schlichting🇩🇪 · Pragya Singh🇩🇪

    We perform an analytic calculation of the color fields in heavy-ion collisions by considering the collision of longitudinally extended nuclei in the dilute limit of the Color Glass Condensate effective field theory of high-energy QCD. Based on general analytic expressions for the color fields in the future light cone, we evaluate the rapidity profile of the transverse pressure within a simple specific model of the nuclear collision geometry and compare our results to 3+1D classical Yang-Mills simulations.

    hep-phnucl-thPRD(2021)·32 citations
11. 11*

    Scotogenic neutrino masses with gauged matter parity and gauge coupling unification

    A. E. Cárcamo Hernández🇨🇱 · Chandan Hati🇩🇪 · Sergey Kovalenko🇨🇱 · José W. F. Valle🇪🇸 · Carlos A. Vaquera-Araujo🇲🇽

    Building up on previous work we propose a Dark Matter (DM) model with gauged matter parity and dynamical gauge coupling unification, driven by the same physics responsible for scotogenic neutrino mass generation. Our construction is based on the extended gauge group \3311, whose spontaneous breaking leaves a residual conserved matter parity, $M_P$, stabilizing the DM particle candidates of the model. A key role is played by the Majorana $\mathrm{SU}(3{)}_{\mathrm{L}}$-octet leptons, in allowing successful gauge coupling unification and one-loop scotogenic neutrino mass generation. Theoretical consistency allows for a \emph{plethora} of new particles at the $\text{lsim}\mathcal{O}$(10) TeV scale, hence accessible to future collider and low-energy experiments.

    hep-phJHEP(2022)·14 citations
12. 12*

    Neutrino Up-scattering via the Dipole Portal at Forward LHC Detectors

    Ahmed Ismail🇺🇸 · Sudip Jana🇩🇪 · Roshan Mammen Abraham🇺🇸

    The significant neutrino flux at high rapidity at the LHC motivates dedicated forward detectors to study the properties of neutrinos at TeV energies. We investigate magnetic dipole interactions between the active neutrinos and new sterile states at emulsion and liquid argon experiments that could be located in a future Forward Physics Facility (FPF) downstream of the ATLAS interaction point. The up-scattering of neutrinos off electrons produces an electron recoil signature that can probe new regions of parameter space at the High Luminosity LHC (HL-LHC), particularly for liquid argon detectors due to low momentum thresholds. We also consider the decay of the sterile neutrino through the dipole operator, which leads to a photon that could be displaced from the production vertex. FPF detectors can test sterile neutrino states as heavy as 1 GeV produced through the dipole portal, highlighting the use of high energy LHC neutrinos as probes of new physics.

    hep-phastro-ph.HEhep-exPRD(2022)·57 citations
13. 13*

    Bubble Clustering in Cosmological First Order Phase Transitions

    Dalila Pirvu🇨🇦 · Jonathan Braden🇨🇦 · Matthew C. Johnson🇨🇦

    False vacuum decay in quantum mechanical first order phase transitions is a phenomenon with wide implications in cosmology, and presents interesting theoretical challenges. In the standard approach, it is assumed that false vacuum decay proceeds through the formation of bubbles that nucleate at random positions in spacetime and subsequently expand. In this paper we investigate the presence of correlations between bubble nucleation sites using a recently proposed semi-classical stochastic description of vacuum decay. This procedure samples vacuum fluctuations, which are then evolved using classical lattice simulations. We compute the two-point function for bubble nucleation sites from an ensemble of simulations, demonstrating that nucleation sites cluster in a way that is qualitatively similar to peaks in random Gaussian fields. We qualitatively assess the phenomenological implications of bubble clustering in early Universe phase transitions, which include features in the power spectrum of stochastic gravitational waves and an enhancement or suppression of the probability of observing bubble collisions in the eternal inflation scenario.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2022)·26 citations
14. 14*

    The hadronic contribution to the running of the electromagnetic coupling and electroweak mixing angle

    Teseo San José🇩🇪 · Marco Cè🇨🇭 · Antoine Gérardin🇫🇷 · Georg von Hippel🇩🇪 · Harvey B. Meyer🇩🇪 · Kohtaroh Miura🇩🇪 · Konstantin Ottnad🇩🇪 · Andreas Risch🇩🇪 · Jonas Wilhelm🇩🇪 · Hartmut Wittig🇩🇪

    As present and future experiments, on both the energy and precision frontiers, look to identify new physics beyond the Standard Model, we require more precise determinations of fundamental quantities, like the QED and electroweak couplings at various momenta. These can be obtained either entirely from experimental measurements, or from one such measurement at a particular virtuality combined with the couplings' virtuality dependence computed within the SM. Thus, a precise, entirely theoretical determination of the running couplings is highly desirable, even more since the preliminary results of the E989 experiment in Fermilab were published. We give results for the hadronic contribution to the QED running coupling $\alpha (Q^2)$ and weak mixing angle ${\sin }^2{\theta }_W(Q^2)$ in the space-like energy region $(0,7]{\text{GeV}}^2$ with a total relative uncertainty of $2\%$ at energies $Q^2\ll 1{\text{GeV}}^2$, and $1\%$ at $Q^2>1{\text{GeV}}^2$.

    ↳ hep-lathep-phPoS(2022)·2 citations
15. 15*

    Charm (and bottom) baryons and charmonium excitations from the lattice

    M. Padmanath🇩🇪

    This report discusses some recent investigations of the heavy hadron spectra using lattice QCD. The first half addresses multiple precision determinations of the masses of charm (and bottom) baryons. Recent lattice results in the tetraquark and the dibaryon sectors are also presented. The second half focuses on new exploratory studies of the excited charmonium spectra in the vector and scalar channels. Along the way, lattice results are compared with the experimental results, wherever they are available.

    ↳ hep-lathep-exhep-phPoS(2021)·3 citations
16. 16*

    Large $N$ external-field quantum electrodynamics

    Felix Karbstein🇩🇪

    We advocate the study of external-field quantum electrodynamics with $N$ charged particle flavors. Our main focus is on the Heisenberg-Euler effective action for this theory in the large $N$ limit which receives contributions from all loop orders. The contributions beyond one loop stem from one-particle reducible diagrams. We show that specifically in constant electromagnetic fields the latter are generated by the one-loop Heisenberg-Euler effective Lagrangian. Hence, in this case the large $N$ Heisenberg-Euler effective action can be determined explicitly at any desired loop order. We demonstrate that further analytical insights are possible for electric-and magnetic-like field configurations characterized by the vanishing of one of the secular invariants of the electromagnetic field and work out the all-orders strong field limit of the theory.

    ↳ hep-thhep-phJHEP(2022)·12 citations
17. 17*

    More on the Weak Gravity Conjecture via Convexity of Charged Operators

    Oleg Antipin🇭🇷 · Jahmall Bersini🇭🇷 · Francesco Sannino🇩🇰 · Zhi-Wei Wang🇩🇰 · Chen Zhang🇮🇹

    The Weak Gravity Conjecture has recently been re-formulated in terms of a particle with non-negative self-binding energy. Because of the dual conformal field theory (CFT) formulation in the anti-de Sitter space the conformal dimension $\Delta (Q)$ of the lowest-dimension operator with charge Q under some global U(1) symmetry must be a convex function of Q. This property has been conjectured to hold for any (unitary) conformal field theory and generalized to larger global symmetry groups. Here we refine and further test the convex charge conjecture via semiclassical computations for fixed charge sectors of different theories in different dimensions. We analyze the convexity properties of the leading and next-to-leading order terms stemming from the semiclassical computation, de facto, extending previous tests beyond the leading perturbative contributions and to arbitrary charges. In particular, the leading contribution is sufficient to test convexity in the semiclassical computations. We also consider intriguing cases in which the models feature a transition from real to complex conformal dimensions either as a function of the charge or number of matter fields. As a relevant example of the first kind, we investigate the $O(N)$ model in $4+ϵ$ dimensions. As an example of the second type we consider the $U(N)\times U(M)$ model in $4-ϵ$ dimensions. Both models display a rich dynamics where, by changing the number of matter fields and/or charge, one can achieve dramatically different physical regimes. We discover that whenever a complex conformal dimension appears, the real part satisfies the convexity property.

    ↳ hep-thgr-qchep-lathep-phJHEP(2021)·27 citations
18. 18*

    Relativistic, model-independent determination of electromagnetic finite-size effects beyond the point-like approximation

    M. Di Carlo🇬🇧 · M. T. Hansen🇬🇧 · N. Hermansson-Truedsson🇨🇭 · A. Portelli🇬🇧

    We present a relativistic and model-independent method to derive structure-dependent electromagnetic finite-size effects. This is a systematic procedure, particularly well-suited for automatization, which works at arbitrarily high orders in the large-volume expansion. Structure-dependent coefficients appear as zero-momentum derivatives of physical form factors which can be obtained through experimental measurements or auxiliary lattice calculations. As an application we derive the electromagnetic finite-size effects on the pseudoscalar meson mass and leptonic decay amplitude, through orders $\mathcal{O}(1/L^3)$ and $\mathcal{O}(1/L^2)$, respectively. The structure dependence appears at this order through the meson charge radius and the real radiative leptonic amplitude, which are known experimentally.

    ↳ hep-lathep-phhep-thPRD(2022)·29 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.