Thu·Jun 10, 2021Thursday·June 10, 2021

1. 01*

   Gradient expansion technique for inhomogeneous, magnetized quark matter

   Filippo Anzuini🇦🇺 · Andrew Melatos🇦🇺

   A quark-magnetic Ginzburg-Landau (qHGL) gradient expansion of the free energy of two-flavor inhomogeneous quark matter in a magnetic field $H$ is derived analytically. It can be applied away from the Lifshitz point, generalizing standard Ginzburg-Landau techniques. The thermodynamic potential is written as a sum of the thermal contribution, the non-thermal lowest Landau level contribution, and the non-thermal qHGL functional, which handles any arbitrary position-dependent periodic modulation of the chiral condensate as an input. The qHGL approximation has two main practical features: (1) it is fast to compute; (2) it applies to non-plane-wave modulations such as solitons even when the amplitude of the condensate and its gradients are large (unlike standard Ginzburg-Landau techniques). It agrees with the output of numerical techniques based on standard regularization schemes and reduces to known results at zero temperature ($T=0$) in benchmark studies. It is found that the region of the $\mu$-$T$ plane (where $\mu$ is the chemical potential) occupied by the inhomogeneous phase expands, as $H$ increases and $T$ decreases.

   hep-phEPJA(2021)·3 citations
2. 02*

   Light mesons with one dynamical gluon on the light front

   Jiangshan Lan🇨🇳 · Kaiyu Fu🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · james P. Vary🇺🇸

   We obtain the light meson mass spectroscopy from the light-front quantum chromodynamics (QCD) Hamiltonian, determined for their constituent quark-antiquark and quark-antiquark-gluon Fock components, together with a three-dimensional confinement. The eigenvectors of the light-front effective Hamiltonian provide a good quality description of the pion electromagnetic form factor, decay constant, and the valence quark distribution functions following QCD scale evolution. We also show that the pion's gluon densities can be probed through the pion-nucleus induced $J/\psi$ production data. Our pion parton distribution functions provide excellent agreement with $J/\psi$ production data from widely different experimental conditions.

   hep-phnucl-thPLB(2022)·77 citations
3. 03*

   Signatures of primordial black hole dark matter at DUNE and THEIA

   Valentina De Romeri🇪🇸 · Pablo Martínez-Miravé🇪🇸 · Mariam Tórtola🇪🇸

   Primordial black holes (PBHs) are a potential dark matter candidate whose masses can span over many orders of magnitude. If they have masses in the $10^{15}-10^{17}$ g range, they can emit sizeable fluxes of MeV neutrinos through evaporation via Hawking radiation. We explore the possibility of detecting light (non-)rotating PBHs with future neutrino experiments. We focus on two next generation facilities: the Deep Underground Neutrino Experiment (DUNE) and THEIA. We simulate the expected event spectra at both experiments assuming different PBH mass distributions and spins, and we extract the expected 95% C.L. sensitivities to these scenarios. Our analysis shows that future neutrino experiments like DUNE and THEIA will be able to set competitive constraints on PBH dark matter, thus providing complementary probes in a part of the PBH parameter space currently constrained mainly by photon data.

   hep-phastro-ph.COhep-exJCAP(2021)·38 citations
4. 04*

   Bayesian estimation of the specific shear and bulk viscosity of the quark-gluon plasma with additional flow harmonic observables

   J.E. Parkkila🇫🇮 · A. Onnerstad🇫🇮 · D.J. Kim🇫🇮

   The transport properties of the strongly-coupled quark-gluon plasma created in ultra-relativistic heavy-ion collisions are extracted by Bayesian parameter estimate methods with the latest collision beam energy data from LHC. This Bayesian analysis includes sophisticated flow harmonic observables for the first time. We found that the temperature dependence of specific shear viscosity shows weaker than the previous studies. The results prefer a lower value of specific bulk viscosity and a higher switching temperature to reproduce additional observables. However, the improved statistical uncertainties both on the experimental data and hydrodynamic calculations with additional observables do not help to reduce the final credibility ranges much, indicating a need for improving the dynamical collision model before the hydrodynamic takes place. In addition, the sensitivities of experimental observables to the parameters in hydrodynamic model calculations are quantified. It is found that the analysis benefits most from the symmetric cumulants and non-linear flow modes, which mostly reflect non-linear hydrodynamic responses, in constraining the temperature dependence of the specific shear and bulk viscosity in addition to the previously used flow coefficients.

   hep-phPRC(2021)·114 citations
5. 05*

   FlexibleDecay: An automated calculator of scalar decay widths

   Peter Athron🇨🇳 · Adam Büchner🇩🇪 · Dylan Harries🇨🇿 · Wojciech Kotlarski🇩🇪 · Dominik Stöckinger🇩🇪 · Alexander Voigt🇩🇪

   We present FlexibleDecay, a tool to calculate decays of scalars in a broad class of BSM models. The tool aims for high precision particularly in the case of Higgs boson decays. In the case of scalar and pseudoscalar Higgs boson decays the known higher order SM QED, QCD and EW effects are taken into account where possible. The program works in a modified $\overline{\text{MS}}$ scheme that exhibits a decoupling property with respect to heavy BSM physics, with BSM parameters themselves treated in the $\overline{\text{MS}}/\overline{\text{DR}}$-scheme allowing for an easy connection to high scale tests for, e.g., perturbativity and vacuum stability, and the many observable calculations readily available in $\overline{\text{MS}}/\overline{\text{DR}}$ programs. Pure BSM effects are taken into account at the leading order, including all one-loop contributions to loop-induced processes. The program is implemented as an extension to FlexibleSUSY, which determines the mass spectrum for arbitrary BSM models, and does not require any extra configuration from the user. We compare our predictions for Higgs decays in the SM, singlet extended SM, type II THDM, CMSSM and MRSSM, as well as for squark decays in the CMSSM against a selection of publicly available tools. The numerical differences between our and other programs are explained. The release of FlexibleDecay officially deprecates the old effective couplings routines in FlexibleSUSY.

   hep-phhep-exComput.Phys.Commun.(2023)·26 citations
6. 06*

   Dark Matter Effects on Compact Binary Stars

   Ebrahim Hassani🇮🇷 · Reza Pazhouhesh🇺🇸

   As compact binary star systems move inside the halo of the galaxies, they interact with dark matter particles. The interaction between dark matter particles and baryonic matter causes dark matter particles to lose some part of their kinetic energy. Once dark matter particles lose part of their kinetic energy, they are gravitationally bound to stars, and stars start to absorb dark matter particles from the halo. The absorption of dark matter particles inside compact binary systems increases the mass of the binary components, and then the total mass of the binary systems increases as well. According to Kepler's third law, increased mass through this way can affect other physical parameters (e.g., semi-major axes and orbital periods) of these systems too. We estimate the period change of some known compact binary systems due to the accretion of dark matter particles into them. We investigate the effects of different dark matter particle candidates with masses in the range $\simeq 10^{-9}-10^5(GeV.c^{-2})$ and dark matter density as high as the dark matter density near the Galactic central regions. We find that the estimated change of period due to the accretion of dark matter particles into compact binary systems can be as large as the measured values for these systems.

   hep-phastro-ph.CO1 citation
7. 07*

   Lepton flavour violation in rare ${\Lambda }_b$ decays

   Marzia Bordone🇮🇹 · Muslem Rahimi🇩🇪 · K. Keri Vos🇳🇱

   Lepton flavour violation (LFV) naturally occurs in many new physics models, specifically in those explaining the $B$ anomalies. While LFV has already been studied for mesonic decays, it is important to consider also baryonic decays mediated by the same quark transition. In this paper, we study LFV in the baryonic ${\Lambda }_b\to \Lambda {\ell }_1{\ell }_2$ using for the first time a full basis of New Physics operators. We present expected bounds on the branching ratio in a model-independent framework and using two specific new physics models. Finally, we point out the interplay and orthogonality between the baryonic and mesonic LFV searches.

   hep-phEPJC(2021)·16 citations
8. 08*

   Dark matter from a complex scalar singlet: The role of dark CP and other discrete symmetries

   Leonardo Coito🇪🇸 · Carlos Faubel🇪🇸 · Juan Herrero-Garcia🇪🇸 · Arcadi Santamaria🇪🇸

   We study the case of a pseudo-scalar dark matter candidate which emerges from a complex scalar singlet, charged under a global U(1) symmetry, which is broken both explicitly and spontaneously. The pseudo-scalar is naturally stabilized by the presence of a remnant discrete symmetry: dark CP. We study and compare the phenomenology of several simplified models with only one explicit symmetry breaking term. We find that several regions of the parameter space are able to reproduce the observed dark matter abundance while respecting direct detection and invisible Higgs decay limits: in the resonances of the two scalars, featuring the known as forbidden or secluded dark matter, and through non-resonant Higgs-mediated annihilations. In some cases, combining different measurements would allow one to distinguish the breaking pattern of the symmetry. Moreover, this setup admits a light DM candidate at the sub-GeV scale. We also discuss the situation where more than one symmetry breaking term is present. In that case, the dark CP symmetry may be spontaneously broken, thus spoiling the stability of the dark matter candidate. Requiring that this does not happen imposes a constraint on the allowed parameter space. Finally, we consider an effective field theory approach valid in the pseudo-Nambu-Goldstone boson limit and when the U(1) breaking scale is much larger than the electroweak scale.

   hep-phJHEP(2021)·26 citations
9. 09*

   Towards the renormalisation of the Standard Model effective field theory to dimension eight: Bosonic interactions I

   Mikael Chala🇪🇸 · Guilherme Guedes🇪🇸 · Maria Ramos🇪🇸 · Jose Santiago🇪🇸

   We compute the one-loop renormalisation group running of the bosonic Standard Model effective operators to order $v^4/{\Lambda }^4$, with $v\sim 246$ GeV being the electroweak scale and $\Lambda$ the unknown new physics threshold. We concentrate on the effects triggered by pairs of the leading dimension-six interactions, namely those that can arise at tree level in weakly-coupled ultraviolet completions of the Standard Model. We highlight some interesting consequences, including the interplay between positivity bounds and the form of the anomalous dimensions; the non renormalisation of the $S$ and $U$ parameters; or the importance of radiative corrections to the Higgs potential for the electroweak phase transition. As a byproduct of this work, we provide a complete Green basis of operators involving only the Higgs and derivatives at dimension-eight, comprising 13 redundant interactions.

   hep-phSciPost Phys.(2021)·79 citations
10. 10*

    A semi-analytic method to compute Feynman integrals applied to four-loop corrections to the $\overline{\mathrm{MS}}$-pole quark mass relation

    Matteo Fael🇩🇪 · Fabian Lange🇩🇪 · Kay Schönwald🇩🇪 · Matthias Steinhauser🇩🇪

    We describe a method to numerically compute multi-loop integrals, depending on one dimensionless parameter $x$ and the dimension $d$, in the whole kinematic range of $x$. The method is based on differential equations, which, however, do not require any special form, and series expansions around singular and regular points. This method provides results well suited for fast numerical evaluation and sufficiently precise for phenomenological applications. We apply the approach to four-loop on-shell integrals and compute the coefficient function of eight colour structures in the relation between the mass of a heavy quark defined in the $\overline{\mathrm{MS}}$ and the on-shell scheme allowing for a second non-zero quark mass. We also obtain analytic results for these eight coefficient functions in terms of harmonic polylogarithms and iterated integrals. This allows for a validation of the numerical accuracy.

    hep-phJHEP(2021)·53 citations
11. 11*

    Inverse Seesaw, dark matter and the Hubble tension

    Enrique Fernandez-Martinez🇪🇸 · Mathias Pierre🇪🇸 · Emanuelle Pinsard🇫🇷 · Salvador Rosauro-Alcaraz🇪🇸

    We consider the inverse Seesaw scenario for neutrino masses with the approximate Lepton number symmetry broken dynamically by a scalar with Lepton number two. We show that the Majoron associated to the spontaneous symmetry breaking can alleviate the Hubble tension through its contribution to $\Delta N_{\text{eff}}$ and late decays to neutrinos. Among the additional fermionic states required for realizing the inverse Seesaw mechanism, sterile neutrinos at the keV-MeV scale can account for all the dark matter component of the Universe if produced via freeze-in from the decays of heavier degrees of freedom.

    hep-phastro-ph.COhep-thEPJC(2021)·35 citations
12. 12*

    Extracting Bigravity from String Theory

    Dieter Lust🇩🇪 · Chrysoula Markou🇩🇪 · Pouria Mazloumi🇩🇪 · Stephan Stieberger🇩🇪

    The origin of the graviton from string theory is well understood: it corresponds to a massless state in closed string spectra, whose low-energy effective action, as extracted from string scattering amplitudes, is that of Einstein-Hilbert. In this work, we explore the possibility of such a string-theoretic emergence of ghost-free bimetric theory, a recently proposed theory that involves two dynamical metrics, that around particular backgrounds propagates the graviton and a massive spin-2 field, which has been argued to be a viable dark matter candidate. By choosing to identify the latter with a massive spin-2 state of open string spectra, we compute tree-level three-point string scattering amplitudes that describe interactions of the massive spin-2 with itself and with the graviton. With the mass of the external legs depending on the string scale, we discover that extracting the corresponding low-energy effective actions in four spacetime dimensions is a subtle but consistent process and proceed to appropriately compare them with bimetric theory. Our findings consist in establishing that string and bimetric theory provide to lowest order the same set of two-derivative terms describing the interactions of the massive spin-2 with itself and with the graviton, albeit up to numerical coefficient discrepancies, a fact that we analyze and interpret. We conclude with a mention of future investigations.

    ↳ hep-thgr-qchep-phJHEP(2021)·40 citations
13. 13*

    Calculating the Higgs Mass in String Theory

    Steven Abel🇬🇧 · Keith R. Dienes🇺🇸

    In this paper, we establish a fully string-theoretic framework for calculating one-loop Higgs masses directly from first principles in perturbative closed string theories. Our framework makes no assumptions other than worldsheet modular invariance and is therefore applicable to all closed strings, regardless of the specific string construction utilized. This framework can also be employed even when spacetime supersymmetry is broken (and even when this breaking occurs at the Planck scale), and can be utilized for all scalar Higgs fields, regardless of the particular gauge symmetries they break. This therefore includes the Higgs field responsible for electroweak symmetry breaking in the Standard Model. Notably, using our framework, we demonstrate that a gravitational modular anomaly generically relates the Higgs mass to the one-loop cosmological constant, thereby yielding a string-theoretic connection between the two fundamental quantities which are known to suffer from hierarchy problems in the absence of spacetime supersymmetry. We also discuss a number of crucial issues involving the use and interpretation of regulators in UV/IR-mixed theories such as string theory, and the manner in which one can extract an EFT description from such theories. Finally, we analyze the running of the Higgs mass within such an EFT description, and uncover the existence of a "dual IR" region which emerges at high energies as the consequence of an intriguing scale-inversion duality symmetry. We also identify a generic stringy effective potential for the Higgs fields in such theories. Our results can therefore serve as the launching point for a rigorous investigation of gauge hierarchy problems in string theory.

    ↳ hep-thhep-phPRD(2021)·54 citations
14. 14*

    Wigner SU(4) symmetry, clustering, and the spectrum of ${}^{12}$C

    Shihang Shen🇩🇪 · Timo A. Lähde🇩🇪 · Dean Lee🇺🇸 · Ulf-G. Meißner🇩🇪

    We present lattice calculations of the low-lying spectrum of ${}^{12}$C using a simple nucleon-nucleon interaction that is independent of spin and isospin and therefore invariant under Wigner's SU(4) symmetry. We find strong signals for all excited states up to $\sim 15$~MeV above the ground state, and explore the structure of each state using a large variety of $\alpha$ cluster and harmonic oscillator trial states, projected onto given irreducible representations of the cubic group. We are able to verify earlier findings for the $\alpha$ clustering in the Hoyle state and the second $2^{+}$ state of ${}^{12}$C. The success of these calculations to describe the full low-lying energy spectrum using spin-independent interactions suggest that either the spin-orbit interactions are somewhat weak in the ${}^{12}$C system, or the effects of $\alpha$ clustering are diminishing their influence. This is in agreement with previous findings from {\it ab initio} shell model calculations.

    ↳ nucl-thhep-lathep-phnucl-exEPJA(2021)·23 citations
15. 15*

    Proca equation and vector field quantization in rotating system

    Tian Xu🇨🇳 · Yin Jiang🇨🇳

    A strong background field will change the vacuum structure and the proper basis of a system drastically in both classical and quantum mechanics, e.g. the Landau levels in a background magnetic field. The situation is the same for the rotating case. In such a system the usual set of plane-wave states would no longer be suitable as a starting point of perturbation. Alternatively and straightforwardly in a rapidly and globally rotating system, it is better to reformulate the perturbation computation in principle. In this work we will complete the first step for the spin-1 field, which includes solving the Proca equation in present of a background rotation and complete its canonical quantization. It will be shown that because of the symmetry the eigen states are actually the same as the ones of Maxwell equations in cylindrical coordinate. The propagator as well as the near-central approximation will be obtained by considering the vorticity areas are so small in the relativistic QGP.

    ↳ hep-thhep-phnucl-thCPC(2021)·6 citations
16. 16*

    Smooth Bubbling Geometries Without Supersymmetry

    Ibrahima Bah🇺🇸 · Pierre Heidmann🇺🇸

    We construct the first smooth bubbling geometries using the Weyl formalism. The solutions are obtained from Einstein theory coupled to a two-form gauge field in six dimensions with two compact directions. We classify the charged Weyl solutions in this framework. Smooth solutions consist of a chain of Kaluza-Klein bubbles that can be neutral or wrapped by electromagnetic fluxes, and are free of curvature and conical singularities. We discuss how such topological structures are prevented from gravitational collapse without struts. When embedded in type IIB, the class of solutions describes D1-D5-KKm solutions in the non-BPS regime, and the smooth bubbling solutions have the same conserved charges as a static four-dimensional non-extremal Cvetic-Youm black hole.

    ↳ hep-thgr-qchep-phJHEP(2021)·51 citations
17. 17*

    The Multiverse in an Inverted Island

    Kevin Langhoff🇺🇸 · Chitraang Murdia🇺🇸 · Yasunori Nomura🇺🇸

    We study the redundancies in the global spacetime description of the eternally inflating multiverse using the quantum extremal surface prescription. We argue that a sufficiently large spatial region in a bubble universe has an entanglement island surrounding it. Consequently, the semiclassical physics of the multiverse, which is all we need to make cosmological predictions, can be fully described by the fundamental degrees of freedom associated with certain finite spatial regions. The island arises due to mandatory collisions with collapsing bubbles, whose big crunch singularities indicate redundancies of the global spacetime description. The emergence of the island and the resulting reduction of independent degrees of freedom provides a regularization of infinities which caused the cosmological measure problem.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2021)·35 citations
18. 18*

    Three-loop color-kinematics duality: A 24-dimensional solution space induced by new generalized gauge transformations

    Guanda Lin🇨🇳 · Gang Yang🇨🇳 · Siyuan Zhang🇨🇳

    We obtain full-color three-loop three-point form factors of the stress-tensor supermultiplet and also of a length-3 half-BPS operator in N=4 SYM based on the color-kinematics duality and on-shell unitarity. The integrand results are verified by all planar and non-planar unitarity cuts, and they satisfy the minimal power-counting of loop momenta and diagrammatic symmetries. Interestingly, these three-loop solutions, while manifesting all dual Jacobi relations, contain a large number of free parameters; in particular, there are 24 free parameters for the form factor of stress-tensor supermultiplet. Such degrees of freedom are due to a new type of generalized gauge transformation associated with the operator insertion for form factors. We also perform numerical integration and obtain consistent full-color infrared divergences and the known planar remainder. The form factors we obtain can be understood as the N=4 SYM counterparts of three-loop Higgs plus three-gluon amplitudes in QCD and are expected to provide the maximally transcendental parts of the latter.

    ↳ hep-thhep-phPRL(2021)·30 citations
19. 19*

    CaloFlow: Fast and Accurate Generation of Calorimeter Showers with Normalizing Flows

    Claudius Krause🇺🇸 · David Shih🇺🇸

    We introduce CaloFlow, a fast detector simulation framework based on normalizing flows. For the first time, we demonstrate that normalizing flows can reproduce many-channel calorimeter showers with extremely high fidelity, providing a fresh alternative to computationally expensive GEANT4 simulations, as well as other state-of-the-art fast simulation frameworks based on GANs and VAEs. Besides the usual histograms of physical features and images of calorimeter showers, we introduce a new metric for judging the quality of generative modeling: the performance of a classifier trained to differentiate real from generated images. We show that GAN-generated images can be identified by the classifier with nearly 100% accuracy, while images generated from CaloFlow are better able to fool the classifier. More broadly, normalizing flows offer several advantages compared to other state-of-the-art approaches (GANs and VAEs), including: tractable likelihoods; stable and convergent training; and principled model selection. Normalizing flows also provide a bijective mapping between data and the latent space, which could have other applications beyond simulation, for example, to detector unfolding.

    ↳ physics.ins-detcs.LGhep-exhep-ph+1PRD(2023)·182 citations
20. 20*

    Linking the Singularities of Cosmological Correlators

    Daniel Baumann🇳🇱 · Wei-Ming Chen🇳🇱 · Carlos Duaso Pueyo🇳🇱 · Austin Joyce🇳🇱 · Hayden Lee🇺🇸 · Guilherme L. Pimentel🇳🇱

    Much of the structure of cosmological correlators is controlled by their singularities, which in turn are fixed in terms of flat-space scattering amplitudes. An important challenge is to interpolate between the singular limits to determine the full correlators at arbitrary kinematics. This is particularly relevant because the singularities of correlators are not directly observable, but can only be accessed by analytic continuation. In this paper, we study rational correlators, including those of gauge fields, gravitons, and the inflaton, whose only singularities at tree level are poles and whose behavior away from these poles is strongly constrained by unitarity and locality. We describe how unitarity translates into a set of cutting rules that consistent correlators must satisfy, and explain how this can be used to bootstrap correlators given information about their singularities. We also derive recursion relations that allow the iterative construction of more complicated correlators from simpler building blocks. In flat space, all energy singularities are simple poles, so that the combination of unitarity constraints and recursion relations provides an efficient way to bootstrap the full correlators. In many cases, these flat-space correlators can then be transformed into their more complex de Sitter counterparts. As an example of this procedure, we derive the correlator associated to graviton Compton scattering in de Sitter space, though the methods are much more widely applicable.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2022)·167 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.