Thu·Mar 11, 2021Thursday·March 11, 2021

1. 01*

   Electroweak phase transition triggered by fermion sector

   Qing-Hong Cao🇨🇳 · Katsuya Hashino🇨🇳 · Xu-Xiang Li🇨🇳 · Zhe Ren🇨🇳 · Jiang-Hao Yu🇨🇳

   To realize first-order electroweak phase transition, it is necessary to generate a barrier in the thermal Higgs potential, which is usually triggered by scalar degree of freedom. We instead investigate phase transition patterns in pure fermion extensions of the standard model, and find that additional fermions with mass hierarchy and mixing could develop such barrier and realize strongly first-order phase transition in such models. In the Higgs potential with polynomial parametrization, the barrier can be generated in the following two patterns: (I) positive quadratic term, negative cubic term and positive quartic term or (II) positive quadratic term, negative quartic term and positive higher dimensional term, such as dimensional 6 operator.

   hep-phJHEP(2022)·11 citations
2. 02*

   Gluon PDF from Quark dressing in the Nucleon and Pion

   Adam Freese🇺🇸 · Ian C. Cloët🇺🇸 · Peter C. Tandy🇺🇸

   Gluon dressing of the light quarks within hadrons is very strong and extremely important in that it dynamically generates most of the observable mass through the breaking of chiral symmetry. The quark and gluon parton densities, $q(x)$ and $g(x)$, are necessarily interrelated since any gluon emission and absorption process, especially dressing of a quark, contributes to $g(x)$ and modifies $q(x)$. Guided by long-established results for the parton-in-parton distributions from a strict 1-loop perturbative analysis of a quark target, we extend the non-perturbative QCD approach based on the Rainbow-Ladder truncation of the Dyson-Schwinger equations to describe the interrelated valence $q_{\mathrm{v}}(x)$ and the dressing-gluon $g(x)$ for a hadron at its intrinsic model scale. We employ the pion description from previous DSE work that accounted for the gluon-in-quark effect and introduce a simple model of the nucleon for exploratory purposes. We find typically \mbox{$⟨x{⟩}_g\sim 0.20$} for both pion and nucleon at the model scale, and the valence quark helicity contributes 52\% of nucleon spin. We deduce both $q_{\mathrm{v}}(x)$ and $g(x)$ from 30 calculated Mellin moments, and after adopting existing data analysis results for $q_{\mathrm{sea}}(x)$, we find that NLO scale evolution produces $g(x)$ in good agreement with existing data analysis results for the pion at 1.3 GeV and the nucleon at 5 GeV${}^2$. At the scale 2 GeV typical of lattice-QCD calculations, we obtain \mbox{$⟨x{⟩}_g^{\mathrm{N}}=0.42$} in good agreement with 0.38 from the average of recent lattice-QCD calculations.

   hep-phhep-latnucl-exnucl-thPLB(2021)·16 citations
3. 03*

   Low-mass inelastic dark matter direct detection via the Migdal effect

   Nicole F. Bell🇦🇺 · James B. Dent🇺🇸 · Bhaskar Dutta🇺🇸 · Sumit Ghosh🇺🇸 · Jason Kumar🇺🇸 · Jayden L. Newstead🇦🇺

   We consider searches for the inelastic scattering of low-mass dark matter at direct detection experiments, using the Migdal effect. We find that there are degeneracies between the dark matter mass and the mass splitting that are difficult to break. Using XENON1T data we set bounds on a previously unexplored region of the inelastic dark matter parameter space. For the case of exothermic scattering, we find that the Migdal effect allows xenon-based detectors to have sensitivity to dark matter with $\mathcal{O}(\mathrm{MeV})$ mass, far beyond what can be obtained with nuclear recoils alone.

   hep-phastro-ph.COPRD(2021)·55 citations
4. 04*

   A multi-component SIMP model with $U(1{)}_X\to Z_2\times Z_3$

   Soo-Min Choi🇩🇪 · Jinsu Kim🇨🇭 · Pyungwon Ko🇰🇷 · Jinmian Li🇨🇳

   Multi-component dark matter scenarios are studied in the model with $U(1{)}_X$ dark gauge symmetry that is broken into its product subgroup $Z_2\times Z_3$ á la Krauss-Wilczek mechanism. In this setup, there exist two types of dark matter fields, $X$ and $Y$, distinguished by different $Z_2\times Z_3$ charges. The real and imaginary parts of the $Z_2$-charged field, $X_R$ and $X_I$, get different masses from the $U(1{)}_X$ symmetry breaking. The field $Y$, which is another dark matter candidate due to the unbroken $Z_3$ symmetry, belongs to the Strongly Interacting Massive Particle (SIMP)-type dark matter. Both $X_I$ and $X_R$ may contribute to $Y$'s $3\to 2$ annihilation processes, opening a new class of SIMP models with a local dark gauge symmetry. Depending on the mass difference between $X_I$ and $X_R$, we have either two-component or three-component dark matter scenarios. In particular two- or three-component SIMP scenarios can be realised not only for small mass difference between $X$ and $Y$, but also for large mass hierarchy between them, which is a new and unique feature of the present model. We consider both theoretical and experimental constraints, and present four case studies of the multi-component dark matter scenarios.

   hep-phastro-ph.COJHEP(2021)·30 citations
5. 05*

   Thermal Relic of Self-Interacting Dark Matter with Retarded Decay of Mediator

   Bin Zhu🇨🇳 · Murat Abdughani🇨🇳

   The existence of a light mediator is beneficial to some phenomena in astroparticle physics, such as the core-cusp problem and diversity problem. It can decouple from Standard Model to avoid direct detection constraints, generally realized by retard decay of the mediator. Their out-of-equilibrium decay process changes the dark matter (DM) freeze-out via temperature discrepancy. This type of hidden sector (HS) typically requires a precision calculation of the freeze-out process considering HS temperature evolution and the thermal average of the cross-section. If the mediator is light sufficiently, we can not ignore the s-wave radiative bound state formation process from the perspective of CMB ionization and Sommerfeld enhancement. We put large mass splitting between DM and mediator, different temperature evolution on the same theoretical footing, discussing the implication for DM relic density in this HS. We study this model and illustrate its property by considering the general Higgs-portal dark matter scenario, which includes all the relevant constraints and signals. It shows that the combination of BBN and CMB constraint favors the not-too-hot HS, $r_{\inf }<10^2$, for the positive cubic interaction of mediator scenario. On the other hand, the negative cubic interaction is ruled out except for our proposed blind spot scenario.

   hep-phastro-ph.HEJHEP(2021)·7 citations
6. 06*

   Semileptonic $B$ decays and $|V_{xb}|$ update

   Giulia Ricciardi🇮🇹

   We review the status of semileptonic $B$ decays and $|V_{xb}|$ determinations.

   hep-phhep-exPoS(2021)·23 citations
7. 07*

   Vector resonance $X_1(2900)$ and its structure

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   The new vector resonance $X_1(2900)$ observed recently by LHCb in the $D^{-}{K}^{+}$ invariant mass distribution in the decay $B^{+}\to D^{+}{D}^{-}{K}^{+}$ is studied to uncover internal structure of this state, and calculate its physical parameters. In the present paper, the resonance $X_1(2900)$ is modeled as an exotic vector state, $J^P=1^{-}$, built of the light diquark $u^{T}C{\gamma }_{5}d$ and heavy antidiquark $\overline{c}{\gamma }_{\mu }{\gamma }_{5}C{\overline{s}}^T$. The mass and current coupling of $X_1(2900)$ are computed using the QCD two-point sum rule approach by taking into account various vacuum condensates up to dimension $10$. The width of the resonance $X_1(2900)$ is saturated by two decay channels $X_1\to D^{-}{K}^{+}$ and $X_1\to {\overline{D}}^0{K}^0$. The strong couplings $g_1$ and $g_2$ corresponding to the vertices $X_1{D}^{-}{K}^{+}$ and $X_1{\overline{D}}^0{K}^0$ are evaluated in the context of the QCD light-cone sum rule method and technical tools of the soft-meson approximation. Results for the mass of the resonance $X_1(2900)$ $m=(2890\pm 122)\mathrm{MeV}$, and for its full width ${\Gamma }_{\mathrm{full}}=(93\pm 13)\mathrm{MeV}$ are smaller than their experimental values reported by the LHCb collaboration. Nevertheless, by taking into account theoretical and experimental errors of investigations, interpretation of the state $X_1(2900)$ as the vector tetraquark does not contradict to the LHCb data. We also point out that analysis of the invariant mass distribution $D^{+}{K}^{+}$ in the same decay $B^{+}\to D^{+}{D}^{-}{K}^{+}$ may reveal doubly charged four-quark structures $[uc][\overline{s}\overline{d}]$.

   hep-phhep-exhep-latNPA(2021)·26 citations
8. 08*

   A local reduction of the Dirac equation applied to the study of quark interactions

   M. De Sanctis🇨🇴

   A general procedure of local reduction for the Dirac equation is introduced to study one- and n-body interacting systems. In the one-body case we show that the reduction allows for an approximate solution of the Dirac equation, correlating the upper and the lower components of the wave function. The two-body case is studied in more detail. We show that the method prevents from introducing spurious, unphysical states. The reduction is also applied to another relativistic equation. Finally, the method is used to construct a specific model in order to study the Charmonium spectrum.

   hep-phActa Phys.Polon.B(2021)·6 citations
9. 09*

   Virtual corrections to $gg\to ZH$ via a transverse momentum expansion

   Lina Alasfar🇩🇪 · Giuseppe Degrassi🇮🇹 · Pier Paolo Giardino🇪🇸 · Ramona Gröber🇮🇹 · Marco Vitti🇮🇹

   We compute the next-to-leading virtual QCD corrections to the partonic cross section of the production of a Higgs boson in association with a $Z$ boson in gluon fusion. The calculation is based on the recently introduced method of evaluating the amplitude via an expansion in terms of a small transverse momentum. We generalize the method to the case of different masses in the final state and of a process not symmetric in the forward-backward direction exchange. Our analytic approach gives a very good approximation (better than percent) of the partonic cross section in the center of mass energy region up to $\sim 750\text{GeV}$, where at the LHC $\sim 98\%$ of the total hadronic cross section is concentrated.

   hep-phJHEP(2021)·35 citations
10. 10*

    The UV sensitivity of the Higgs potential in Gauge-Higgs Unification

    Atsuyuki Yamada🇯🇵

    In this paper, we discuss the UV sensitivity of the Higgs effective potential in a Gauge-Higgs Unification (GHU) model. We consider an $SU(\mathcal{N})$ GHU on ${\mathbf{M}}^4\times S^1$ spacetime with a massless Dirac fermion. In this model, we evaluate the four-Fermi diagrams at the two-loop level and find them to be logarithmically divergent in the dimensional regularization scheme. Moreover, we confirm that their counter terms contribute to the Higgs effective potential at the four-loop level. This result means that the Higgs effective potential in the GHU depends on UV theories as well as in other non-renormalizable theories.

    hep-phPTEP(2021)·3 citations
11. 11*

    Renormalization of the C2HDM with FeynMaster 2

    Duarte Fontes🇵🇹 · Jorge C. Romão🇵🇹

    We present the one-loop electroweak renormalization of the CP-violating 2-Higgs-Doublet Model with softly broken ${\mathbb{Z}}_2$ symmetry (C2HDM). The existence of CP violation in the scalar sector of the model leads to a quite unique process of renormalization, since it requires the introduction of several non-physical parameters. The C2HDM will thus have more independent counterterms than independent renormalized parameters. As a consequence, different combinations of counterterms can be taken as independent for the same set of independent renormalized parameters. We compare the behaviour of selected combinations in specific NLO processes, which are assured to be gauge independent via a simple prescription. FeynMaster 2 is used to derive the Feynman rules, counterterms and one-loop processes in a simultaneously automatic and flexible way. This illustrates its use as an ideal tool to renormalize models such as the C2HDM and investigate them at NLO.

    hep-phJHEP(2021)·28 citations
12. 12*

    Narrow Resonances Revisited -- Simplifying Multidimensional Constraints

    R. Sekhar Chivukula🇺🇸 · Pawin Ittisamai🇹🇭 · James Osborne🇺🇸 · Elizabeth H. Simmons🇺🇸

    As we amass more LHC data, we continue to search for new and improved methods of visualizing search results, in ways that are as model-independent as possible. The simplified limits framework is an approach developed to recast limits on searches for narrow resonances in terms of products of branching ratios (BRs) corresponding to the resonance's production and decay modes. In this work, we extend the simplified limits framework to a multidimensional parameter space of BRs, which can be used to unfold an ambiguity in the simplified parameter $\zeta$ introduced when more than one channel contributes to the production of the resonance. It is also naturally applicable to combining constraints from experimental searches with different observed final states. Constraints can be visualized in a three-dimensional space of branching ratios by employing ternary diagrams, triangle plots which utilize the inherent unitarity of the sum of the resonance's BRs. To demonstrate this new methodology, we recast constraints from recent ATLAS searches in diboson final states for spin-0, 1, and 2 narrow resonances into constraints on the resonance's width-to-mass ratio and display them in the space of relevant branching ratios. We also demonstrate how to generalize the method to cases where more than three branching ratios are relevant by using N-simplex diagrams, and we suggest a broader application of the general method to digital data sets.

    hep-phhep-exPRD(2021)·2 citations
13. 13*

    Searching for Magnetic Monopoles with the Earth's Magnetic Field

    Yang Bai🇺🇸 · Sida Lu🇮🇱 · Nicholas Orlofsky🇨🇦

    Magnetic monopoles have long been predicted in theory and could exist as a stable object in our universe. As they move around in galaxies, magnetic monopoles could be captured by astrophysical objects like stars and planets. Here, we provide a novel method to search for magnetic monopoles by detecting the monopole moment of the Earth's magnetic field. Using over six years of public geomagnetic field data obtained by the Swarm satellites, we apply Gauss's law to measure the total magnetic flux, which is proportional to the total magnetic charge inside the Earth. To account for the secular variation of satellite altitudes, we define an altitude-rescaled magnetic flux to reduce the dominant magnetic dipole contribution. The measured magnetic flux is consistent with the existing magnetic field model that does not contain a monopole moment term. We therefore set an upper limit on the magnetic field strength at Earth's surface from magnetic monopoles to be $|B_{\mathrm{m}}|<0.13$ nT at 95% confidence level, which is less than $2\times 10^{-6}$ of Earth's magnetic field strength. This constrains the abundance of magnetically-charged objects, including magnetic black holes with large magnetic charges.

    hep-phastro-ph.EPPRL(2021)·16 citations
14. 14*

    Quarkyonic Effective Field Theory, Quark-Nucleon Duality and Ghosts

    Dyana C. Duarte🇺🇸 · Saul Hernandez-Ortiz🇺🇸 · Kie Sang Jeong🇺🇸 · Larry D. McLerran🇺🇸

    We present a field theoretical description of quarkyonic matter consisting of quark, nucleon and ghost fields coupling to mesonic degrees of freedom. The ghosts are present to cancel over-counting of nucleon states that are Pauli blocked by the quark Fermi sea. Such a theory becomes an effective field theory of nucleons at low baryon density, and as such will reproduce nucleonic matter phenomenology. This theory can accommodate chiral symmetry restoration and the dynamical generation of a shell of nucleons at the Fermi surface. It is valid for finite temperature and density. In such a theory, quark-nucleon duality is accomplished by inclusion of ghost fields so that the nucleons extra degrees of freedom, that are beyond those of quarks, are compensated by the ghost fields.

    ↳ nucl-thhep-phhep-thPRD(2021)·31 citations
15. 15*

    Apprentice for Event Generator Tuning

    Mohan Krishnamoorthy🇺🇸 · Holger Schulz🇬🇧 · Xiangyang Ju🇺🇸 · Wenjing Wang🇺🇸 · Sven Leyffer🇺🇸 · Zachary Marshall🇺🇸 · Stephen Mrenna🇺🇸 · Juliane Muller🇺🇸 · James B. Kowalkowski🇺🇸

    Apprentice is a tool developed for event generator tuning. It contains a range of conceptual improvements and extensions over the tuning tool Professor. Its core functionality remains the construction of a multivariate analytic surrogate model to computationally expensive Monte-Carlo event generator predictions. The surrogate model is used for numerical optimization in chi-square minimization and likelihood evaluation. Apprentice also introduces algorithms to automate the selection of observable weights to minimize the effect of mis-modeling in the event generators. We illustrate our improvements for the task of MC-generator tuning and limit setting.

    ↳ hep-exhep-phphysics.comp-phEPJ Web Conf.(2021)·35 citations
16. 16*

    BROOD: Bilevel and Robust Optimization and Outlier Detection for Efficient Tuning of High-Energy Physics Event Generators

    Wenjing Wang🇺🇸 · Mohan Krishnamoorthy🇺🇸 · Juliane Muller🇩🇪 · Stephen Mrenna🇺🇸 · Holger Schulz🇬🇧 · Xiangyang Ju🇺🇸 · Sven Leyffer🇺🇸 · Zachary Marshall🇺🇸

    The parameters in Monte Carlo (MC) event generators are tuned on experimental measurements by evaluating the goodness of fit between the data and the MC predictions. The relative importance of each measurement is adjusted manually in an often time-consuming, iterative process to meet different experimental needs. In this work, we introduce several optimization formulations and algorithms with new decision criteria for streamlining and automating this process. These algorithms are designed for two formulations: bilevel optimization and robust optimization. Both formulations are applied to the datasets used in the ATLAS A14 tune and to the dedicated hadronization datasets generated by the sherpa generator, respectively. The corresponding tuned generator parameters are compared using three metrics. We compare the quality of our automatic tunes to the published ATLAS A14 tune. Moreover, we analyze the impact of a pre-processing step that excludes data that cannot be described by the physics models used in the MC event generators.

    ↳ math.NAcs.NAhep-phphysics.comp-phSciPost Phys.Core(2022)·6 citations
17. 17*

    Detectability of "Merger-nova" emission from a long-lived magnetar in short gamma-ray bursts

    Yong Yuan🇨🇳 · Hou-Jun Lü🇨🇳 · Hao-Yu Yuan🇨🇳 · Shuai-Bing Ma🇨🇳 · Wei-Hua Lei🇨🇳 · En-Wei Liang🇨🇳

    One possible progenitor of short gamma-ray bursts (GRBs) is thought to be from a double neutron star (NS) merger, and the remnant of such a merger may be a supramassive NS, which is supported by rigid rotation and through its survival of hundreds of seconds before collapsing into a black hole (BH). If this is the case, an optical/infrared transient (namely merger-nova) is generated from the ejected materials and it is powered by radioactive decay from $r$-process, spin-down energy from a supramassive NS, as well as the magnetic wind from a newborn BH. In this paper, we systematically search for the signature of a supramassive NS central engine by analyzing the X-ray emission of short GRBs with internal plateau observed by {\em Swift}, and we find that five candidates of short GRBs have such feature with redshift measurement. Then, we calculate the possible merger-nova emission from those candidates for given the typical model parameters by considering the above three energy sources, and compare its brightness with the sensitivity of some optical telescopes. We find that the merger-nova emission of GRB 060801 in K-, r-, and U-bands with variations of $M_{\mathrm{ej}}$ ($10^{-4}-10^{-2}{M}_{\odot }$), $\kappa$ ($0.1-10\mathrm{c}{\mathrm{m}}^2{\mathrm{g}}^{-1}$), and $\beta$ ($0.1-0.3$) is very difficult to detect using the Vera C. Rubin, Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), the Zwicky Transient Facility, and the Roman Space Telescope (Roman), except for the case of large ejecta mass $M_{\mathrm{ej}}=10^{-2}{M}_{\odot }$. However, we are very hopeful to detect the merger-nova emission of GRBs 090515, 100625A, and 101219A using more sensitive instruments, such as Vera C. Rubin, Pan-STARRS, and Roman. Moreover, the merger-nova emission of GRB 160821B is bright enough to detect in our calculations, and it is also consistent with current real observations of merger-nova emission.

    ↳ astro-ph.HEhep-phApJ(2021)·17 citations
18. 18*

    Parametric resonance of complex scalar field under spacetime oscillations

    Shreyansh S. Dave🇮🇳 · Sanatan Digal🇮🇳

    In this proceeding, we study time evolution of a complex scalar field, in symmetry broken phase, in presence of oscillating spacetime metric background. We show that spacetime oscillations lead to parametric resonance of the field. This generates excitations in the field for a wide range of frequency of spacetime oscillations which ultimately lead to the formation of topological vortices. The lowest frequency cut-off to induce this phenomena is set by system size due to finite size effects.

    ↳ hep-thastro-ph.HEhep-phnucl-thSpringer Proc.Phys.(2022)·0 citations
19. 19*

    Role of axial U(1) anomaly in chiral susceptibility of QCD at high temperature

    S. Aoki🇯🇵 · Y. Aoki🇯🇵 · H. Fukaya🇯🇵 · S. Hashimoto🇯🇵 · C. Rohrhofer🇯🇵 · K. Suzuki (JLQCD collaboration)🇯🇵

    The chiral susceptibility, or the first derivative of the chiral condensate with respect to the quark mass, is often used as a probe for the QCD phase transition since the chiral condensate is an order parameter of $SU(2{)}_L\times SU(2{)}_R$ symmetry breaking. However, the chiral condensate also breaks the axial $U(1)$ symmetry, which is usually not paid attention to as it is already broken by anomaly and apparently gives little impact on the transition. We investigate the susceptibilities in the scalar and pseudoscalar channels in order to quantify how much the axial $U(1)$ breaking contributes to the chiral phase transition. Employing a chirally symmetric lattice Dirac operator, and its eigenmode decomposition, we separate the axial $U(1)$ breaking effects from others. Our result in two-flavor QCD indicates that both of the connected and disconnected chiral susceptibilities are dominated by the axial $U(1)$ breaking at temperatures $T\gtrsim 190$ MeV after the quadratically divergent constant is subtracted.

    ↳ hep-lathep-phhep-thPTEP(2022)·38 citations
20. 20*

    Axion Isocurvature Collider

    Shiyun Lu🇨🇳

    Cosmological colliders can preserve information from interactions at very high energy scale, and imprint them on cosmological observables. Taking the squeezed limit of cosmological perturbation bispectrum, information of the intermediate particle can be directly extracted from observations such as cosmological microwave background (CMB). Thus cosmological colliders can be powerful and promising tools to test theoretical models. In this paper, we study extremely light axions (including QCD axions and axion-like-particles), and consider them constituting cold dark matter (CDM) at late times. We are interested in inflationary isocurvature modes by such axions, and try to figure out how axion perturbations can behave as isocurvature colliders. We work out an example where the intermediate particle is a boson, and show that, in the squeezed limit, it is possible to provide a clock signal of significant amplitudes, with a characteristic angular dependence. This provides a channel to contribute and analyze clock signals of isocurvature bispectrum, which we may hopefully see in future experiments.

    ↳ hep-thastro-ph.COhep-phJHEP(2022)·50 citations
21. 21*

    Physics performance for Dark Matter searches at $\sqrt{s}=$ 3 TeV at CLIC using mono-photons and polarised beams

    J-J. Blaising🇫🇷 · P. Roloff🇨🇭 · A. Sailer🇨🇭 · U. Schnoor🇨🇭

    The potential for detecting DM at the Compact Linear Collider (CLIC) is investigated at \mbox{$\sqrt{s}=$ 3 TeV}. The sensitivity of the search is estimated by computing the 95\% confidence level upper limit cross section as a function of the dark matter mass. Left-handed (right-handed) polarised \Pem beams increase (decrease) respectively the Standard Model backgrounds and are essential to characterize the WIMPs properties and control the systematic errors. Using right-handed polarised \Pem beams is decreasing significantly the 95\% confidence level cross section. Using the ratio of the energy distributions for left-handed and right-handed polarised \Pem beams, systematic errors cancel out. Computing the 95\% confidence level upper limit cross section using the ratio requires a model assumption to compute the expected number of signal events. Exclusion limits for dark matter are derived using dark matter Simplified Models for two values of the e-e-mediator vertex coupling, a mediator width of 10 GeV and for a fixed value of the mediator-DM-DM coupling. For a mediator mass of 3.5 TeV, the measurement of the differential distribution of the significance as a function of the photon energy for the process \mbox{\Pem \Pep $\to$ X X \PGg} allows the discrimination between different dark matter mediators and the measurement of the WIMP mass to nearly half the centre-of-mass energy. For a \mbox{1 TeV} WIMP, the mass is determined with a 1\% accuracy.

    ↳ hep-exhep-ph19 citations
22. 22*

    Combined Constraints on Majorana Masses from Neutrinoless Double Beta Decay Experiments

    Steven D. Biller🇬🇧

    Combined bounds on the Majorana neutrino mass for light and heavy neutrino exchange mechanisms are derived from current neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) search results for a variety of nuclear matrix element (NME) models. The approach requires self-consistency of a given model to predict NMEs across different isotopes. The derived bounds are notably stronger than those from any single experiment and show less model-to-model variation, highlighting the advantages of using multiple isotopes in such searches. Projections indicate that the combination of near-term experiments should be able to probe well into the inverted mass hierarchy region. A method to visually represent 0{\nu}\b{eta}\b{eta} experimental results is also suggested to more transparently compare across different isotopes and explicitly track model dependencies.

    ↳ hep-exhep-phPRD(2021)·21 citations
23. 23*

    Photo-induced pair production and strong field QED on Gemini

    CH Keitel · A Di Piazza · GG Paulus · T Stoehlker · EL Clark · S Mangles · Z Najmudin · K Krushelnick · J Schreiber · M Borghesi · B Dromey · M Geissler and 3 other authors

    The extreme intensities obtainable with lasers such as Gemini allow non-linear QED phenomena to be investigated according to our calculations. Electron-positron pair production from a pure vacuum target, which has yet to be observed experimentally, is possibly the most iconic process. Beyond pair-production our campaign will allow the experimental investigation of currently unexplored extreme radiation regimes, like the quantum radiation dominated regime (where quantum and self-field effects become important) and non-linear Compton scattering. This is the first experiment in a multi-part campaign proposed by a major international collaboration to investigate non-linear QED. This proposal is for the first experiment in a series of 3 to achieve our most high-profile experimental goal of pair production in vacuum, but each experiment is designed to have its own tangible high-profile outcome.

    ↳ physics.plasm-phhep-exhep-ph17 citations
24. 24*

    Symmetry meets AI

    Gabriela Barenboim🇪🇸 · Johannes Hirn🇪🇸 · Veronica Sanz🇪🇸

    We explore whether Neural Networks (NNs) can {\it discover} the presence of symmetries as they learn to perform a task. For this, we train hundreds of NNs on a {\it decoy task} based on well-controlled Physics templates, where no information on symmetry is provided. We use the output from the last hidden layer of all these NNs, projected to fewer dimensions, as the input for a symmetry classification task, and show that information on symmetry had indeed been identified by the original NN without guidance. As an interdisciplinary application of this procedure, we identify the presence and level of symmetry in artistic paintings from different styles such as those of Picasso, Pollock and Van Gogh.

    ↳ cs.LGcs.CVhep-phSciPost Phys.(2021)·26 citations
25. 25*

    Bekenstein-Hod Universal Bound on Information Emission Rate Is Obeyed by LIGO-Virgo Binary Black Hole Remnants

    Gregorio Carullo🇮🇹 · Danny Laghi🇮🇹 · John Veitch🇬🇧 · Walter Del Pozzo🇮🇹

    Causality and the generalized laws of black hole thermodynamics imply a bound, known as the \textit{Bekenstein--Hod universal bound}, on the information emission rate of a perturbed system. Using a time-domain ringdown analysis, we investigate whether remnant black holes produced by the coalescences observed by Advanced LIGO and Advanced Virgo obey this bound. We find that the bound is verified by the astrophysical black hole population with $94\%$ probability, providing a first confirmation of the Bekenstein--Hod bound from black hole systems.

    ↳ gr-qchep-phPRL(2021)·36 citations
26. 26*

    Quantum sensitivity limits of nuclear magnetic resonance experiments searching for new fundamental physics

    Deniz Aybas🇺🇸 · Hendrik Bekker🇩🇪 · John W. Blanchard🇩🇪 · Dmitry Budker🇩🇪 · Gary P. Centers🇩🇪 · Nataniel L. Figueroa🇩🇪 · Alexander V. Gramolin🇺🇸 · Derek F. Jackson Kimball🇺🇸 · Arne Wickenbrock🇩🇪 · Alexander O. Sushkov🇺🇸

    Nuclear magnetic resonance is a promising experimental approach to search for ultra-light axion-like dark matter. Searches such as the cosmic axion spin-precession experiments (CASPEr) are ultimately limited by quantum-mechanical noise sources, in particular, spin-projection noise. We discuss how such fundamental limits can potentially be reached. We consider a circuit model of a magnetic resonance experiment and quantify three noise sources: spin-projection noise, thermal noise, and amplifier noise. Calculation of the total noise spectrum takes into account the modification of the circuit impedance by the presence of nuclear spins, as well as the circuit back-action on the spin ensemble. Suppression of the circuit back-action is especially important in order for the spin-projection noise limits of searches for axion-like dark matter to reach the quantum chromodynamic axion sensitivity.

    ↳ quant-phcond-mat.otherhep-phphysics.ins-detQuantum Sci.Technol.(2021)·37 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.