Wed·May 12, 2021Wednesday·May 12, 2021

1. 01*

   NASDUCK: New Constraints on Axion-like Dark Matter from Floquet Quantum Detector

   Itay M. Bloch🇮🇱 · Gil Ronen🇮🇱 · Roy Shaham🇮🇱 · Ori Katz🇮🇱 · Tomer Volansky🇮🇱 · Or Katz (for the NASDUCK Collaboration)

   We report on the first results of the Noble and Alkali Spin Detectors for Ultralight Coherent darK matter (NASDUCK) collaboration. We search for the interactions of Axion-Like Particles (ALPs) with atomic spins using an earth-based precision quantum detector as it traverses through the galactic dark matter halo. The detector is composed of spin-polarized xenon gas which can coherently interact with a background ALP dark matter field and an in-situ rubidium Floquet optical-magnetometer. Conducting a five months-long search, we derive new constraints on ALP-proton and ALP-neutron interactions in the $4\times 10^{-15}-4\times 10^{-12}eV/{\mathrm{c}}^2$ mass range. Our limits on the ALP-proton (ALP-neutron) couplings improve upon previous terrestrial bounds by up to 3 orders of magnitude for masses above $4\times 10^{-14}eV/{\mathrm{c}}^2$ ($4\times 10^{-13}eV/{\mathrm{c}}^2$). Moreover, barring the uncertain supernova constraints, the ALP-proton bound improves on all existing terrestrial and astrophysical limits, partially closing the unexplored region for couplings in the range $10^{-6}\mathrm{Ge}{\mathrm{V}}^{-1}$ to $2\times 10^{-5}\mathrm{Ge}{\mathrm{V}}^{-1}$. Finally, we also cast bounds on pseudo-scalar dark matter models in which dark matter is quadratically-coupled to the nucleons.

   hep-phhep-exphysics.atom-phquant-phSci.Adv.(2022)·89 citations
2. 02*

   European Spallation Source: a future for Coherent Neutrino Nucleus Scattering

   Ivan Esteban🇺🇸

   The European Spallation Source (ESS), currently finishing its construction, will soon provide the most intense neutron beams for multi-disciplinary science. At the same time, it will also produce a high-intensity neutrino flux with an energy suitable for precision measurements of Coherent Elastic Neutrino-Nucleus Scattering. We describe some physics prospects, within and beyond the Standard Model, of employing innovative detector technologies to take the most out of this large flux. We show that, compared to current measurements, the ESS will provide a much more precise understanding of neutrino and nuclear properties.

   hep-phhep-exnucl-exnucl-th3 citations
3. 03*

   A gauged non-universal $U(1{)}_X$ model to study muon $g-2$ and $B$ meson anomalies

   J. S. Alvarado🇫🇷 · S. F. Mantilla🇩🇪 · R. Martinez🇨🇴 · F. Ochoa🇨🇴 · Cristian Sierra🇨🇳

   We study a non-universal $U(1{)}_X$ extension of the Standard Model with an extended scalar sector of two doublets and one singlet plus three additional exotic quarks and two exotic charged leptons on the fermionic sector. In order to obtain the observed fermion mass hierarchy, an additional ${\mathbb{Z}}_2$ discrete symmetry is imposed, where the heaviest fermions acquire their masses from three different scales determined by two Higgs doublets and one singlet, whereas the lightest fermions obtain their masses from effective operators up to dimension seven. From chiral anomalies cancellation, the model also includes heavy right-handed neutrinos which get massive via an inverse see-saw mechanism, reproducing the observed mass differences for the active neutrinos. We analyze phenomenological consequences of the model in view of the so-called flavour anomalies, namely the latest measurement made by Fermilab of the anomalous magnetic moment of the muon $g-2$, and additionally, the fit to semi-leptonic $B$ meson decays made by different flavour groups, dominated mainly by the LHCb 2020 data. We obtain that the model can explain the former at the $1\sigma$ level by means of contributions coming from charged $W^{+}$ bosons interacting with exotic Majorana neutrinos at one-loop level, with the $Z^{\prime }$ boson contribution itself coming from the $U(1{)}_X$ symmetry being negligible. However, we find that the model is able to accommodate the $b\to s{\ell }^{+}{\ell }^{-}$ transitions associated to the $B$ meson anomalies only at the $2\sigma$ level via tree-level $Z^{\prime }$ boson exchange, while simultaneously respecting various constraints from the recent $R_{K^{(\ast )}}$ measurements made by the LHCb, neutrino trident production and $B-\bar{B}$ oscillations.

   hep-phPRD(2023)·18 citations
4. 04*

   Quantum Simulations of the Non-Unitary Time Evolution and Applications to Neutral-Kaon Oscillations

   Ying Chen🇨🇳 · Yunheng Ma🇨🇳 · Shun Zhou🇨🇳

   In light of recent exciting progress in building up quantum computing facilities based on both optical and cold-atom techniques, the algorithms for quantum simulations of particle-physics systems are in rapid progress. In this paper, we propose an efficient algorithm for simulating the non-unitary time evolution of neutral-kaon oscillations $K^0\leftrightarrow {\overline{K}}^0$, with or without CP conservation, on the quantum computers provided by the IBM company. The essential strategy is to realize the time-evolution operator with basic quantum gates and an extra qubit corresponding to some external environment. The final results are well consistent with theoretical expectations, and the algorithm can also be applied to open systems beyond elementary particles.

   hep-phhep-exquant-ph4 citations
5. 05*

   Conformal mappings in perturbative QCD

   Irinel Caprini🇷🇴

   We discuss the method of conformal mappings applied to perturbative QCD. The approach is based on the Borel-Laplace integral regulated with the principal value prescription and the expansion of the Borel transform in powers of the variable which performs the conformal mapping of the cut Borel plane onto the unit disk. We write down the expression of the conformal mapping for the most general location of the singularities of the Borel transform and review the properties of the corresponding expansions of the correlators. Unlike the standard perturbative expansions, which are divergent, the modified expansions have a tamed behaviour at large orders and may even converge under some conditions. On the other hand, the expansion functions exhibit nonperturbative features similar to those of the expanded function. Using these properties, it was suggested recently that the expansions based on the conformal mapping of the Borel plane may provide an alternative to the standard OPE. We briefly review the arguments in favour of this conjecture and discuss the application of the method to the Adler function for massless quarks and the static quark self-energy calculated in lattice QCD.

   hep-phEur.Phys.J.ST(2021)·6 citations
6. 06*

   Disentangling the hard gluon Bremsstrahlung effects from the relative transverse activity classifier in pp collisions

   Gyula Bencedi🇲🇽 · Antonio Ortiz🇲🇽 · Antonio Paz🇲🇽

   Recently, the so-called relative transverse activity classifier, $R_{\mathrm{T}}$, has been proposed as a tool to disentangle the particle production originated from the soft and hard QCD processes in proton-proton (pp) collisions. $R_{\mathrm{T}}$ is a useful quantity to study particle production in events with exceptionally large or small activity in the transverse region with respect to the event-averaged mean. Contrary to the expectations, the preliminary results of the ALICE Collaboration indicate that, e.g., the proton-to-pion ratio does not exhibit the characteristic enhancement at intermediate $p_{\mathrm{T}}$ in events with large $R_{\mathrm{T}}$ with respect to minimum-bias pp collisions. In this work, we investigate the origin of this effect using the PYTHIA 8 and HERWIG 7 Monte Carlo event generators. The effect is a consequence of a selection bias attributed to wide-angle gluon emissions which creates jets that populate the transverse region. Therefore, we propose a modified version of $R_{\mathrm{T}}$ in order to suppress its sensitivity to hard gluon Bremsstrahlung, and enhance the sensitivity to soft Multiparton Interactions (MPI). This approach could be useful in order to study the particle production in the jet-like region as a function of MPI. The implementation of these ideas in data will provide more insight into the production mechanisms of hadrons in high-multiplicity pp collisions, and its connection with heavy-ion phenomena.

   hep-phPRD(2021)·24 citations
7. 07*

   Complete Lagrangian and Set of Feynman Rules for Scalar Leptoquarks

   Andreas Crivellin🇨🇭 · Luc Schnell🇫🇷

   Leptoquarks (LQs) have attracted increasing attention within recent years, mainly since they can explain the flavor anomalies found in $R(D^{(\ast )})$, $b\to s{\ell }^{+}{\ell }^{-}$ transitions and the anomalous magnetic moment of the muon. In this article, we lay the groundwork for further automated analyses by presenting the complete Lagrangian and the corresponding set of Feynman rules for scalar leptoquarks. This means we consider the five representations ${\Phi }_1,{\Phi }_{\tilde{1}},{\Phi }_2,{\Phi }_{\tilde{2}}$ and ${\Phi }_3$ and include the triple and quartic self-interactions, as well as couplings to the Standard Model (SM) fermions, gauge bosons and the Higgs. The calculations are performed using FeynRules and all model files are publicly available online at https://gitlab.com/lucschnell/SLQrules.

   hep-phhep-exComput.Phys.Commun.(2022)·46 citations
8. 08*

   Goldstone boson decays and chiral anomalies

   Stefan Pokorski🇵🇱 · Kazuki Sakurai🇵🇱

   Martinus Veltman was the first to point out the inconsistency of the experimental value for the decay rate of ${\pi }^0\to \gamma \gamma$ and its calculation by J. Steinberger with the very successful concept of the pion as the (pseudo)Nambu-Goldstone boson of the spontaneously broken global axial symmetry of strong interactions. That inconsistency has been resolved by J. Bell and R. Jackiw in their famous paper on the chiral anomalies. We review the connection between the decay amplitudes of an axion into two gauge bosons in Abelian vector-like and chiral gauge theories. The axion is the Nambu-Goldstone boson of a spontaneously broken axial global symmetry of the theory. Similarly as for the vector-like gauge theory, also in the chiral one the axion decay amplitude is determined by the anomaly of the current of the axial symmetry in its non-linear realization. Certain subtlety in the calculation of the anomaly in chiral gauge theories is emphasised.

   hep-phActa Phys.Polon.B(2021)·3 citations
9. 09*

   Model independent analysis of coupled-channel scattering: a deep learning approach

   Denny Lane B. Sombillo🇵🇭 · Yoichi Ikeda🇯🇵 · Toru Sato🇯🇵 · Atsushi Hosaka🇯🇵

   We develop a robust method to extract the pole configuration of a given partial-wave amplitude. In our approach, a deep neural network is constructed where the statistical errors of the experimental data are taken into account. The teaching dataset is constructed using a generic S-matrix parametrization, ensuring that all the poles produced are independent of each other. The inclusion of statistical error results into a noisy classification dataset which we should solve using the curriculum method. As an application, we use the elastic $\pi N$ amplitude in the $I(J^P)=1/2(1/2^{-})$ sector where $10^6$ amplitudes are produced by combining points in each error bar of the experimental data. We fed the amplitudes to the trained deep neural network and find that the enhancements in the $\pi N$ amplitude are caused by one pole in each nearby unphysical sheet and at most two poles in the distant sheet. Finally, we show that the extracted pole configurations are independent of the way points in each error bar are drawn and combined, demonstrating the statistical robustness of our method.

   hep-phhep-exnucl-exnucl-thPRD(2021)·28 citations
10. 10*

    Indirect detection constraints on the scotogenic dark matter model

    T. de Boer🇩🇪 · R. Busse🇩🇪 · A. Kappes🇩🇪 · M. Klasen🇩🇪 · S. Zeinstra🇩🇪

    Radiative seesaw models have the attractive property of providing dark matter candidates in addition to the generation of neutrino masses. Here we present a study of neutrino signals from the annihilation of dark matter particles that have been gravitationally captured in the Sun in the framework of the scotogenic model. We compute expected event rates in the IceCube detector in its 86-string configuration. As fermionic dark matter does not scatter off nucleons due to its singlet nature and therefore does not accumulate in the Sun, we study the case of scalar dark matter with a scan over the parameter space. Due to a naturally small mass splitting between the two neutral scalar components, inelastic scattering processes with nucleons can occur. We find that for most of the parameter space, i.e. for mass splittings below 500 keV, inelastic scattering in the Sun yields IceCube event rates above 10 events per year, whereas direct detection on Earth is sensitive only to 250 keV. Consequently, a detailed analysis with IceCube could lead to a lower limit on the scalar coupling ${\lambda }_5\gtrsim 1.6\cdot 10^{-5}\cdot m_{DM}$/TeV. For larger mass splittings, only elastic scattering occurs in the Sun. In this case, XENON1T limits only allow for models with expected event rates of up to O(0.1) per year. Some of these models, in particular those with large DM mass and fermion coannihilation, could also be tested with a dedicated IceCube analysis of DM annihilation in the Galactic Center.

    hep-phhep-exJCAP(2021)·19 citations
11. 11*

    The scalars $a_0(980)$ and $f_0(980)$ in the process $D_s^{+}\to K^{+}{K}^{-}{\pi }^{+}$

    Jun-Ya Wang🇨🇳 · Man-Yu Duan🇨🇳 · Guan-Ying Wang🇨🇳 · De-Min Li🇨🇳 · Li-Juan Liu🇨🇳 · En Wang🇨🇳

    In this work, we have investigated the process $D_s^{+}\to K^{+}{K}^{-}{\pi }^{+}$, taking into account the contributions from the $S$-wave pseudoscalar-pseudoscalar interaction within the chiral unitary approach, and also the intermediate $\varphi$ resonance. By analyzing the BESIII and {\it BABAR} measurements, we conclude that the $f_0(980)$ state, dynamically generated from the $S$-wave pseudoscalar-pseudoscalar interaction, gives the dominant contribution close to the $K^{+}{K}^{-}$ threshold in the $K^{+}{K}^{-}$ invariant mass distribution of the decay $D_s^{+}\to K^{+}{K}^{-}{\pi }^{+}$ in $S$-wave. On the other hand, our results imply that the lineshape adopted by BESIII and {\it BABAR} for the resonances $a_0(980)$ and $f_0(980)$ is not advisable in the fit to the data close to the $K^{+}{K}^{-}$ threshold.

    hep-phPLB(2021)·26 citations
12. 12*

    Influence of chiral asymmetry on phase structure of the two-color quark matter

    T. G. Khunjua🇬🇪 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺

    In this paper the influence of chiral chemical potential ${\mu }_5$ on the phenomenon of diquark condensation and phase structure of dense quark matter altogether is contemplated in the framework of effective two-color and two-flavor Nambu--Jona-Lasinio model. We show that the duality relations, found ${\mu }_5=0$, are also valid for any value of ${\mu }_5\ne 0$. Hence the dualities seem to be a real fundamental feature of the phase diagram of two color quark matter, and besides they are a very powerful tool of studying the phase structure. In terms of dualities and the influence on the phase diagram chiral imbalance ${\mu }_5$ stands alone from other chemical potentials. Two regimes in the phase diagram could be discerned, the first one, rather small or moderate values of chemical potentials ${\mu }_B$, ${\mu }_I$ and ${\mu }_{I5}$, where the picture is rather concise and elegant: each of the above phenomena is in one-to-one correspondence with some chemical potential (${\mu }_{I5}$ induces chiral symmetry breaking, ${\mu }_I$ propels charged pion condensation and ${\mu }_B$ leads to diquark condensation). In this regime chiral chemical potential ${\mu }_5$ does not break this correspondence, it has a property of being universal catalyzer, i.e. it {\it catalyzes/enhances} all the phenomena on equal footing. The feature of chiral imbalance ${\mu }_5$ to catalyze chiral symmetry breaking phenomenon was known before but its catalytic properties appeared to be more universal and it can catalyze also diquark and charged pion condensation. These happen due to the dual properties. In the second regime, when several chemical potentials reach rather large values, one could observe a rather complicated and rich phase structure, and ${\mu }_5$ can be a factor that not so much catalyzes as {\it triggers} rather peculiar phases. For example, it can lead to the formation of diquark condensation at zero baryon chemical potential.

    hep-phnucl-thPRD(2022)·22 citations
13. 13*

    Parton splitting scales of reclustered large-radius jets in high-energy nuclear collisions

    Shan-Liang Zhang🇨🇳 · Meng-Quan Yang🇨🇳 · Ben-Wei Zhang🇨🇳

    We carry out the first theoretical investigation on yields and the hardest parton splitting of large-radius jets reclustered from small radius ($R=0.2$) anti-$k_t$ jets in Pb+Pb collisions, and confront them with the recent ATLAS measurements.The Linear Boltzmann Transport (LBT) model is employed for jet propagation and jet-induced medium excitation in the hot-dense medium. We demonstrate that, with their complex structures, the medium suppression of the reclustered large radius jets at $R=1$ is larger than that of inclusive $R=0.4$ jets defined conventionally. The large radius jet constituents are reclustered with the $k_t$ algorithm to obtain the splitting scale $\sqrt{d_{12}}$, which characterizes the transverse momentum scale for the hardest splitting in the jet. The large-radius jet production as a function of the splitting scale $\sqrt{d_{12}}$ of the hardest parton splitting is overall suppressed in Pb+Pb relative to p+p collisions due to the reduction of jets yields. A detailed analyses show that the alterations of jet substructures in Pb+Pb also make significant contribution to the splitting scale $\sqrt{d_{12}}$ dependence of the nuclear modification factor $R_{AA}$. Numerical results for the medium modifications of the jet splitting angle $\Delta R_{12}$ and the splitting fraction $z$ are also presented.

    hep-phEPJC(2022)·15 citations
14. 14*

    Anomalies in B mesons decays: Present status and future collider prospects

    Jorge Alda🇪🇸 · Jaume Guasch🇪🇸 · Siannah Penaranda🇪🇸

    The experimental measurements on flavour physics, in tension with Standard Model predictions, exhibit large sources of Lepton Flavour Universality violation. This note summarises an analysis of the effects of the global fits to the Wilson coefficients assuming a model independent effective Hamiltonian approach, by including a proposal of different scenarios to include the New Physics contributions. Additionally, we include an overview of the impact of the future generation of colliders in the field of B-meson anomalies.

    hep-ph7 citations
15. 15*

    Boosted and semi-boosted all-hadronic $t\bar{t}$ reconstruction performance on kinematic variables for selected BSM models using a 2D extesion of the BumpHunter algorithm

    Jiri Kvita🇨🇿

    We explore the usage of boosted as well as semi-boosted topologies in all-hadronic $t\bar{t}$ final states in simulated $pp$ collisions at $\sqrt{s}=14$TeV, with top quarks decaying into a boosted hadronic top-jet or a $W$-jet and an isolated $b$-jet. Correlations between selected kinematic variables and their shapes are studied for scalar and vector resonances decaying to a pair of top quarks, and also for a models of $t\bar{t}$-associated production with an invisible dark matter particle pair. Stacked signal$+$background samples have been investigated in terms of the ability to resolve an excess of events over the Standard Model background in terms of the $t\bar{t}$ invariant mass, top quark transverse momentum and other 1D and 2D spectra using a parameterized detector simulation. A 2D extension of the BumpHunter algorithm is proposed, resulting in an improved signal sensitivity in specific 2D areas. We identify the most promising variables with the largest signal significance and smaller sensitivity to experimental uncertainties realated to the jet energy calibration. We compare to statistical tests computing the background-only hypothesis compatibility and a likelihood fit of the signal strength.

    hep-phhep-exInt.J.Mod.Phys.A(2024)·0 citations
16. 16*

    Correlation of Theoretical Uncertainties in PDF Fits and Theoretical Uncertainties in Predictions

    Richard D. Ball🇬🇧 · Rosalyn L. Pearson🇬🇧

    We show how to account for correlations between theoretical uncertainties incorporated in parton distribution function (PDF) fits, and the theoretical uncertainties in the predictions made using these PDFs. We demonstrate by explicit calculations, both analytical and numerical, that these correlations can lead to corrections to the central values of the predictions, and reductions in both the PDF uncertainties and the theoretical uncertainties in the prediction. We illustrate our results with predictions for top production rapidity distributions and the Higgs total cross-section at the LHC, using the NLO NNPDF3.1 PDF set which incorporates missing higher order uncertainties. We conclude that the inclusion of correlations can increase both the accuracy and precision of predictions involving PDFs, particularly for processes with data already included in the PDF fit.

    hep-phEPJC(2021)·43 citations
17. 17*

    Extended Calculation of Dark Matter-Electron Scattering in Crystal Targets

    Sinéad M. Griffin🇺🇸 · Katherine Inzani🇺🇸 · Tanner Trickle🇺🇸 · Zhengkang Zhang🇺🇸 · Kathryn M. Zurek🇺🇸

    We extend the calculation of dark matter direct detection rates via electronic transitions in general dielectric crystal targets, combining state-of-the-art density functional theory calculations of electronic band structures and wave functions near the band gap, with semi-analytic approximations to include additional states farther away from the band gap. We show, in particular, the importance of all-electron reconstruction for recovering large momentum components of electronic wave functions, which, together with the inclusion of additional states, has a significant impact on direct detection rates, especially for heavy mediator models and at $\mathcal{O}(10\text{eV})$ and higher energy depositions. Applying our framework to silicon and germanium (that have been established already as sensitive dark matter detectors), we find that our extended calculations can appreciably change the detection prospects. Our calculational framework is implemented in an open-source program $\text{EXCEED-DM}$ (EXtended Calculation of Electronic Excitations for Direct detection of Dark Matter), to be released in an upcoming publication.

    hep-phastro-ph.COcond-mat.mtrl-sciPRD(2021)·95 citations
18. 18*

    Neutron star structure with a new force between quarks

    Jeffrey M. Berryman🇺🇸 · Susan Gardner🇺🇸

    The discovery of nondiffuse sources of gravitational waves through compact-object mergers opens new prospects for the study of physics beyond the Standard Model. In this paper, we study the effects of a new force between quarks, suggested by the gauging of baryon number, on pure neutron matter at supranuclear densities. This leads to a stiffening of the equation of state, allowing neutron stars to be both larger and heavier and possibly accommodating the light progenitor of GW190814 as a neutron star. The role of conventional three-body forces in neutron star structure is still poorly understood, though they can act in a similar way, implying that the mass and radius do not in themselves resolve whether new physics is coming into play. However, a crucial feature of the scenario we propose is that the regions of the new physics parameter space that induce observable changes to neutron star structure are testable at low-energy accelerator facilities. This testability distinguishes our scenario from other classes of new phenomena in dense matter.

    hep-phastro-ph.HEnucl-thPRC(2021)·11 citations
19. 19*

    New Thermal Relic Targets for Inelastic Vector-Portal Dark Matter

    Patrick J. Fitzpatrick🇺🇸 · Hongwan Liu🇺🇸 · Tracy R. Slatyer🇺🇸 · Yu-Dai Tsai🇺🇸

    We examine the vector-portal inelastic dark matter (DM) model with DM mass $m_{\chi }$ and dark photon mass $m_{A^{\prime }}$, in the `forbidden dark matter' regime where $1\lesssim m_{A^{\prime }}/m_{\chi }\lesssim 2$, carefully tracking the dark sector temperature throughout freezeout. The inelastic nature of the dark sector relaxes the stringent cosmic microwave background (CMB) and self-interaction constraints compared to symmetric DM models. We determine the CMB limits on both annihilations involving excited states and annihilation into $e^{+}{e}^{-}$ through initial-state-radiation of an $A^{\prime }$, as well as limits on the DM self-scattering, which proceeds at the one-loop level. The unconstrained parameter space serves as an ideal target for accelerator $A^{\prime }$ searches, and provides a DM self-interaction cross section that is large enough to observably impact small-scale structure.

    hep-phastro-ph.COPRD(2022)·31 citations
20. 20*

    Synergies of top and $B$ anomalies in SMEFT

    Stefan Bißmann🇩🇪 · Cornelius Grunwald🇩🇪 · Gudrun Hiller🇩🇪 · Kevin Kröninger🇩🇪

    We present constraints on Wilson coefficients from a combined fit to data from top-quark and beauty-physics measurements within the Standard Model effective field theory. We consider present data on top-quark pair production and decay, $b\to s$ flavor changing neutral currents, and $Z\to b\bar{b}$ decay, as well as different future scenarios. These comprise projections for HL-LHC, Belle II, and a lepton collider using the example of CLIC. We investigate opportunities for detecting deviations from the Standard Model hinted at by present data on $b\to s$ transitions. In the fit, we find strong synergies between top-quark and beauty physics that allow to tighten constraints on various coefficients.

    hep-phhep-ex1 citation
21. 21*

    Infrared Divergences and the Eikonal Exponentiation

    Carlo Heissenberg🇸🇪

    The aim of this note is to explore the interplay between the eikonal resummation in impact-parameter space and the exponentiation of infrared divergences in momentum space for gravity amplitudes describing collisions of massive objects. The eikonal governs the classical dynamics relevant to the two-body problem, and its infrared properties are directly linked to the zero-frequency limit of the gravitational wave emission spectrum and to radiation-reaction effects. Combining eikonal and infrared exponentiations it is possible to derive these properties at a given loop order starting from lower-loop data. This is illustrated explicitly in $\mathcal{N}=8$ supergravity and in general relativity by deriving the divergent part of the two-loop eikonal from tree-level and one-loop elastic amplitudes.

    ↳ hep-thgr-qchep-phPRD(2021)·64 citations
22. 22*

    Effects of a background scalar field induced by the Lorentz symmetry violation on Non Relativistic Quantum Mechanics

    J. D. García-Aguilar🇲🇽

    The extension of Standard Model of the Fundamental Particles which consider the Lorentz Symmetry Violation governed by a background tensor field presented by Colladay and Kostelecky consider the hypothesis of having a privileged direction in the space-time. Here we investigated a extension of the Schrödinger Equation inspired on that model taking into account a background scalar field. We analyze the behavior of this modified Schrödinger equation on a particle trapped in a well and quantum harmonic oscillator.

    ↳ quant-phhep-ph0 citations
23. 23*

    On Conformal Transformation with Multiple Scalar Fields and Geometric Property of Field Space with Einstein-like Solutions

    Yong Tang🇨🇳 · Yue-Liang Wu🇨🇳

    Multiple scalar fields appear in vast modern particle physics and gravity models. When they couple to gravity non-minimally, conformal transformation is utilized to bring the theory into Einstein frame. However, the kinetic terms of scalar fields are usually not canonical, which makes analytic treatment difficult. Here we investigate under what conditions the theories can be transformed to the quasi-canonical form, in which case the effective metric tensor in field space is conformally flat. We solve the relevant nonlinear partial differential equations for arbitrary number of scalar fields and present several solutions that may be useful for future phenomenological model building, including the $\sigma$-model with a particular non-minimal coupling. We also find conformal flatness can always be achieved in some modified gravity theories, for example, Starobinsky model.

    ↳ gr-qcastro-ph.COhep-phPRD(2021)·4 citations
24. 24*

    Model investigations of the correlation between the mean transverse momentum and anisotropic flow in shape-engineered events

    Niseem Magdy🇺🇸 · Roy A. Lacey🇺🇸

    The correlation between the event mean-transverse momentum $[p_{\mathrm{T}}]$, and the anisotropic flow magnitude $v_n$, $\rho (v_n^2,[p_T])$, has been argued to be sensitive to the initial conditions in heavy-ion collisions. We use simulated events generated with the AMPT and EPOS models for Au+Au at $\sqrt{{\text{s}}_{NN}}$ = 200 GeV, to investigate the model dependence and the response and sensitivity of the $\rho (v_2^2,[p_T])$ correlator to collision-system size and shape, and the viscosity of the matter produced in the collisions. We find good qualitative agreement between the correlators for the string melting version of the AMPT model and the EPOS model. The model investigations for shape-engineered events as well as events with different viscosity ($\eta /s$), indicate that $\rho (v_2^2,[p_T])$ is sensitive to the initial-state geometry of the collision system but is insensitive to sizable changes in $\eta /s$ for the medium produced in the collisions. These findings suggest that precise differential measurements of $\rho (v_2^2,[p_T])$ as a function of system size, shape, and beam-energy could provide more stringent constraints to discern between initial-state models and hence, more reliable extractions of $\eta /s$.

    ↳ nucl-thhep-phnucl-exPLB(2021)·12 citations
25. 25*

    Multimessenger constraints for ultra-dense matter

    Eemeli Annala🇫🇮 · Tyler Gorda🇩🇪 · Evangelia Katerini🇬🇷 · Aleksi Kurkela🇳🇴 · Joonas Nättilä🇺🇸 · Vasileios Paschalidis🇺🇸 · Aleksi Vuorinen🇫🇮

    Recent rapid progress in neutron-star (NS) observations offers great potential to constrain the properties of strongly interacting matter under the most extreme conditions. In order to fully exploit the current observational inputs and to study the impact of future observations of NS masses, radii, and tidal deformabilities, we analyze a large ensemble of randomly generated viable NS-matter equations of state (EoSs) and the corresponding rotating stellar structures. We discuss the compatibility and impact of various hypotheses and measurements on the EoS, including those involving the merger product of the gravitational-wave (GW) event GW170817, the binary merger components in GW190814, and radius measurements of the pulsar PSR J0740+6620. We obtain an upper limit for the dimensionless spin of a rigidly rotating NS, $|\chi |<0.81$, an upper limit for the compactness of a NS, $GM/(R{c}^2)<0.33$, and find that the conservative hypothesis that the remnant in GW170817 ultimately collapsed to a black hole strongly constrains the EoS and the maximal mass of NSs, implying $M_{\text{TOV}}<2.53M_{\odot }$ (or $M_{\text{TOV}}<2.19M_{\odot }$ if we assume that a hypermassive NS was created). Additionally, we derive a novel lower limit for the tidal deformability as a function of NS mass and provide fitting formulae that can be used to set priors for parameter estimation and to discern whether neutron stars or other compact objects are involved in future low-mass GW events. Finally, we find that the recent NICER results for the radius of the massive NS PSR J0740+6620 place strong constraints for the behavior of the EoS, and that the indicated radius values $R(2M_{\odot })\gtrsim 11$ km are compatible with moderate speeds of sound in NS matter and thus with the existence of quark matter cores in massive NSs.

    ↳ astro-ph.HEgr-qchep-phnucl-thPRX(2022)·199 citations
26. 26*

    r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae

    Xilu Wang · Adam M. Clark · John Ellis · Adrienne F. Ertel · Brian D. Fields · Zhenghai Liu · Jesse A. Miller · Rebecca Surman

    The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron star mergers (kilonovae (KNe)) contribute, and some classes of core-collapse supernovae (SNe) are also likely sources of at least the lighter r-process species. The discovery of 60Fe on the Earth and Moon implies that one or more astrophysical explosions have occurred near the Earth within the last few million years, probably SNe. Intriguingly, 244Pu has now been detected, mostly overlapping with 60Fe pulse. However, the 244Pu flux may extend to before 12 Myr ago, pointing to a different origin. Motivated by these observations and difficulties for r-process nucleosynthesis in SN models, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble, where the Sun resides. Accelerator mass spectrometry (AMS) measurements of 244Pu and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., that at the end of the Devonian epoch, motivating the calculations of the abundances of live r-process radioisotopes produced in SNe and KNe that we present here. Given the presence of 244Pu, other r-process species such as 93Zr, 107Pd, 129I, 135Cs, 182Hf, 236U, 237Np and 247Cm should be present. Their abundances and well-resolved time histories could distinguish between the SN and KN scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. We show that AMS 129I measurements in Fe-Mn crusts already constrain a possible nearby KN scenario.

    ↳ astro-ph.HEhep-phnucl-exnucl-th+1ApJ(2021)·24 citations
27. 27*

    Challenges for $\Lambda$CDM: An update

    Leandros Perivolaropoulos🇬🇷 · Foteini Skara🇬🇷

    A number of challenges to the standard $\Lambda$CDM model have been emerging during the past few years as the accuracy of cosmological observations improves. In this review we discuss in a unified manner many existing signals in cosmological and astrophysical data that appear to be in some tension ($2\sigma$ or larger) with the standard $\Lambda$CDM model as specified by the Cosmological Principle, General Relativity and the Planck18 parameter values. In addition to the well-studied $5\sigma$ challenge of $\Lambda$CDM (the Hubble $H_0$ tension) and other well known tensions (the growth tension, and the lensing amplitude $A_L$ anomaly), we discuss a wide range of other less discussed less-standard signals which appear at a lower statistical significance level than the $H_0$ tension some of them known as 'curiosities' in the data) which may also constitute hints towards new physics. For example such signals include cosmic dipoles (the fine structure constant $\alpha$, velocity and quasar dipoles), CMB asymmetries, BAO Ly$\alpha$ tension, age of the Universe issues, the Lithium problem, small scale curiosities like the core-cusp and missing satellite problems, quasars Hubble diagram, oscillating short range gravity signals etc. The goal of this pedagogical review is to collectively present the current status (2022 update) of these signals and their level of significance, with emphasis on the Hubble tension and refer to recent resources where more details can be found for each signal. We also briefly discuss theoretical approaches that can potentially explain some of these signals.

    ↳ astro-ph.COgr-qchep-phhep-thNew Astron.Rev.(2022)·1264 citations
28. 28*

    The Amplitude for Classical Gravitational Scattering at Third Post-Minkowskian Order

    N. E. J. Bjerrum-Bohr🇩🇰 · P. H. Damgaard🇩🇰 · L. Planté🇫🇷 · P. Vanhove🇫🇷

    We compute the scattering amplitude for classical black-hole scattering to third order in the Post-Minkowskian expansion, keeping all terms needed to derive the scattering angle to that order from the eikonal formalism. Our results confirm a conjectured relation between the real and imaginary parts of the amplitude by Di Vecchia, Heissenberg, Russo, and Veneziano, and are in agreement with a recent computation by Damour based on radiation reaction in general relativity.

    ↳ hep-thgr-qchep-phJHEP(2021)·211 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.