Thu·Sep 21, 2023Thursday·September 21, 2023

1. 01*

   One-loop Matching and Running via On-shell Amplitudes

   Xu Li🇨🇳 · Shun Zhou🇨🇳

   In this work, we put forward a straightforward and simple approach to construct the low-energy effective field theory (EFT) from a given ultraviolet (UV) full theory by integrating heavy particles out. By calculating the on-shell amplitudes, we demonstrate how to directly achieve the one-loop matching of the UV full theory onto the EFT with the complete set of independent operators in the physical basis, which are usually obtained by removing the redundant operators in the Green's basis via the equations of motion. Furthermore, taking specific examples, we explain how to implement the on-shell-amplitude approach to derive the one-loop renormalization-group equations for the Wilson coefficients, and to find out the contributions from the evanescent operators.

   hep-ph4 citations
2. 02*

   Gradient-flow renormalon subtraction and the hadronic tau decay series

   Martin Beneke (TU Munich)🇩🇪 · Hiromasa Takaura (Kyoto University)🇯🇵

   The inconsistency between the fixed-order (FO) and contour-improved (CI) representation of the QCD corrections to the inclusive hadronic tau decay width limits the precision to which the strong coupling can be determined from this process. It has recently been shown that subtracting the infrared renormalon divergence related to the gluon condensate resolves the discrepancy. Here we suggest to employ the gradient flow to define gauge-invariant regularized operators and to use the corresponding condensates in the operator product expansion. The associated rearrangement of the perturbative series results in automatic renormalon subtraction without the need to determine explicitly the Stokes constants that normalize the divergent asymptotic series. Applying this method to the gluon condensate, we find that the CI series is modified and now agrees with the (unmodified) FO series. This conclusively demonstrates the preference for the fixed-order approach, as has been advocated long ago.

   hep-phPoS(2024)·11 citations
3. 03*

   Inflation and Higgs Phenomenology in a Model Unifying the DFSZ Axion with the Majoron

   Michael Matlis🇩🇪 · Juhi Dutta🇺🇸 · Gudrid Moortgat-Pick🇩🇪 · Andreas Ringwald🇩🇪

   The Two-Higgs-Doublet-Standard Model-Axion-Seesaw-Higgs-Portal inflation (2hdSMASH) model consisting of two Higgs doublets, a Standard Model (SM) singlet complex scalar and three SM singlet right-handed neutrinos can embed axion dark matter, neutrino masses and address inflation. We report on an investigation of the inflationary aspects of 2hdSMASH and its subsequent impact on low energy phenomenology. In particular, we identify inflationary directions for which the parameter values required for successful inflation do not violate perturbative unitarity and boundedness-from-below conditions. By analyzing the renormalization-group flow of the parameters we identify the necessary and sufficient constraints for running all parameters perturbatively and maintaining stability from the electroweak to the PLANCK scale. We observe that stringent constraints arise on the singlet scalar self coupling from inflationary constraints, i.e, ${\lambda }_S\sim 10^{-10}$. Further, we find that all theoretical and experimental constraints are satisfied if the portal couplings are typically in the range $(\frac{v}{v_S})$ and $(\frac{v}{v_S}{)}^2$ (where $v,v_S$ refer to the electroweak and singlet scalar vacuum expectation value respectively). As a consequence, inflation is realized in a variety of field space directions in the effective single field regime. Finally we provide testable benchmark scenarios at colliders.

   hep-phJCAP(2024)·13 citations
4. 04*

   BFBrain: Scalar Bounded-From-Below Conditions from Bayesian Active Learning

   George N. Wojcik🇺🇸

   We present a procedure leveraging Bayesian deep active learning to rapidly produce highly accurate approximate bounded-from-below conditions for arbitrary renormalizable scalar potentials, in the form of a neural network which may be saved and exported for use in arbitrary parameter space scans. We explore the performance of our procedure on three different scalar potentials with either highly nontrivial or unknown symbolic bounded-from-below conditions (the two-Higgs doublet model, the three-Higgs doublet model, and a version of the Georgi-Machacek model without custodial symmetry). We find that we can produce fast and highly accurate binary classifiers for all three potentials. Furthermore, for the potentials for which no known symbolic necessary and sufficient conditions on boundedness-from-below exist, our classifiers substantially outperform some common approximate analytical methods, such as producing tractable sufficient but not necessary conditions or evaluating boundedness-from-below conditions for scenarios in which only a subset of the theory's fields achieve vev's. Our methodology can be readily adapted to any renormalizable scalar field theory. For the community's use, we have developed a Python package, BFBrain, which allows for the rapid implementation of our analysis procedure on user-specified scalar potentials with a high degree of customizability.

   hep-phPRD(2024)·3 citations
5. 05*

   Energy-momentum tensor of a hydrogen atom: stability, D-term, and the Lamb shift

   Andrzej Czarnecki🇨🇦 · Yizhuang Liu🇵🇱 · Syed Navid Reza🇨🇦

   We clarify two issues related to the so-called $D$-term in matrix elements of the energy-momentum tensor. First, we show that in a stable system, the $D$-term can have either sign, contrary to claims that it must be negative. Second, we demonstrate a logarithmic enhancement of the $\alpha$ correction to the $D$-term in any state of the hydrogen atom. We contrast this enhancement with the Lamb shift where it is present only in S-states.

   hep-phActa Phys.Polon.Supp.(2023)·15 citations
6. 06*

   Cosmic-ray dark matter confronted by constraints on new light mediators

   Nicole F. Bell🇦🇺 · Jayden L. Newstead🇦🇺 · Iman Shaukat-Ali🇦🇺

   The detectability of light dark matter in direct detection experiments is limited by the small kinetic energy of the recoiling targets. Thus, scenarios where dark matter is boosted to relativistic velocities provide a useful tactic to constrain sub-GeV dark matter particles. Of the possible dark matter boosting mechanisms, cosmic-ray upscattering is an appealing paradigm as it doesn't require any additional assumptions beyond dark matter coupling to nucleons or electrons. However, detectable signals are obtained only with relatively large cross sections which, in turn, can only be realized with large couplings, light mediators or composite dark matter. In this work we consider a general set of light mediators that couple dark matter to hadrons. Using data from Borexino, XENON1T, LZ and Super-K, we show that existing constraints on such mediators preclude appreciable cosmic-ray dark matter upscattering. This finding highlights the limited applicability of cosmic-ray upscattering constraints and suggests they only be used in model-dependent studies.

   hep-phPRD(2024)·47 citations
7. 07*

   New Signature of low mass $Z^{\prime }$ in $J/\psi$ decays

   Chao-Qiang Geng🇨🇳 · Chia-Wei Liu🇨🇳 · Jiabao Zhang🇨🇳

   We explore a new approach to search for a low-mass $Z^{\prime }$ particle through $J/\psi$ decays by identifying its existence through parity-violating phenomena in the isospin-violating final states of $\Lambda {\overline{\Sigma }}^0$ and the corresponding charge conjugated states of $\overline{\Lambda }{\Sigma }^0$. Our investigation centers on a generation-independent and leptophobic $Z^{\prime }$ with its mass below 10 GeV. Given the present experimental conditions at the Beijing Spectrometer III~(BESIII) and the anticipated opportunities at the Super Tau Charm Factory~(STCF), we conduct Monte-Carlo simulations to predict possible events at both facilities. Notably, we foresee a substantial enhancement in the precision of the lower limit estimation of ${\alpha }_{\text{NP}}$ as well as a reduction in statistical uncertainty with upcoming STCF experiments. Furthermore, it is essential to highlight that a null result in the measurement of ${\alpha }_{\text{NP}}$ would impose stringent constraints, requiring the $Z^{\prime }-q-q$ couplings to be on the order of $10^{-2}$.

   hep-phhep-exCPC(2024)·0 citations
8. 08*

   The $H\to b\bar{s}$ decay and its implication for the vector-like singlet fermion model

   Jin Zhang🇨🇳 · Hong-Ying Jin🇨🇳 · T. G. Steele🇨🇦

   The vector-like quark model is one of the extensions of the standard model (SM) of particle physics. The simplest version of this model introduces a vector-like singlet quark which can mix with SM quarks and give rise to new contributions to the flavor-changing decays of the Higgs boson. In this work we first present a systematic analysis of the branching ratios of the decays $H\to b\bar{s},b\bar{d}$ at leading order in the standard model. Our results show that it is challenging to observe these two modes because of their small branching ratios. Then augmenting the SM with a vector-like singlet top quark, assuming the top partner only mixes with the top quark, complete one-loop contributions are taken into account in the amplitudes. Further results indicate that the branching ratios of the decays $H\to b\bar{s},b\bar{d}$ are sensitive to the mass of the top partner $M_T$ and the mixing effects characterized by $\sin {\theta }_L$. By tuning the values of $M_T$ and $\sin {\theta }_L$, the branching ratios may rise to a level accessible to LHC experiments. Combined with the branching ratios obtained from a probabilistic model, the allowed areas in the $M_T-\sin {\theta }_L$ plane are displayed. Tagging efficiencies and feasibility for detecting $H\to b\bar{s}$ are specifically discussed and we conclude that with large statistics it is promising to discover the $H\to b\bar{s}$ decay at the LHC.

   hep-phPRD(2024)·1 citation
9. 09*

   Interplay of type-I and type-II seesaw in neutrinoless double beta decay in left-right symmetric model

   Vivek Banerjee🇮🇳 · Sasmita Mishra🇮🇳

   The left-right symmetric models (LRSM) generally include type-I and type-II induced seesaw masses as a hybrid mass for the light-active neutrinos. Assuming a particular form of Dirac-type coupling, the Majorana-type coupling in the seesaw mass formula can be expressed in terms of low-energy neutrino oscillation observables and vacuum expectation values (vevs) of the scalar fields present in the model. The Majorana-type coupling thus admits eight different solutions by considering whether the type-I and type-II terms dominate the light neutrino mass. We study the role of all eight solutions in the lepton number violating neutrinoless double beta decay ($0\nu \beta \beta$) process. In LRSM, the right-handed neutrinos, triplet scalars, and gauge bosons of the left and right sectors mediate new contributions to the $0\nu \beta \beta$ process. As a result, the effective mass of electron neutrino appearing in the decay width would be a function of $v_R$ (vev of the Higgs triplet of the right sector) along with other model parameters, through the masses of the new contributions. The energy scale, $v_R$ can be considered as the new physics scale which allows exploring physics beyond the Standard Model. Considering the present and future sensitivity of searches of $0\nu \beta \beta$, we study the role of eight different solutions of the Majorana coupling matrix. In our study, the inverted hierarchy of light neutrino masses is disfavored for all solutions keeping future sensitivity of effective mass in the picture, if the lightest mass of active neutrinos is below $0.001$ eV. Also, our study shows a possibility of new physics contributions saturating the experimental bound on effective mass for $v_R$ in the range of $10$ TeV for two particular solutions of the Majorana coupling matrix and simultaneously provides the insights about parity breaking scale.

   hep-phNPB(2024)·4 citations
10. 10*

    Rare decays of $B_d$ mesons into four charged leptons in the Standard Model

    A. V. Danilina🇷🇺 · N. V. Nikitin🇷🇺

    We present first theoretical predictions for various observables related to the ${\bar{B}}_d\to {\mu }^{+}{\mu }^{-}{e}^{+}{e}^{-}$ decay within the framework of the Standard Model. Our study encompasses the branching ratios, differential distributions, and forward-backward leptonic asymmetries. To obtain these predictions, we account for several contributions: resonance contribution from $\rho (770)$ and significant contribution $\omega (782)$; contributions from four charmonium resonances: $\psi (3770)$, $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$; additional contributions from the "tails" of $J/\psi$ and $\psi (2S)$ resonances; non-resonant contributions arising from virtual photon emission by a $b$-quark of $B_d$ meson, bremsstrahlung, and weak annihilation. In our calculations we employ the model of vector meson dominance (VMD) to assess the resonance contributions accurately. We provide the predictions for the branching ratio of the ${\bar{B}}_d\to {\mu }^{+}{\mu }^{-}{e}^{+}{e}^{-}$ decay both with and without the resonant contribution from $\omega (782)$.

    hep-phnucl-th0 citations
11. 11*

    A new puzzle in non-leptonic B decays

    Aritra Biswas🇪🇸 · Sébastien Descotes-Genon🇫🇷 · Joaquim Matias🇪🇸 · Gilberto Tetlalmatzi-Xolocotzi🇫🇷

    We propose a set of new optimized observables using penguin mediated ${\bar{B}}_d$ and ${\bar{B}}_s$ decays: ${\bar{B}}_{d,s}\to K^{\ast 0}{\bar{K}}^{\ast 0}$, ${\bar{B}}_{d,s}\to K^0{\bar{K}}^0$, ${\bar{B}}_{d,s}\to K^0{\bar{K}}^{\ast 0}$ and ${\bar{B}}_{d,s}\to {\bar{K}}^0{K}^{\ast 0}$ together with their CP conjugate partners. These observables are substantially cleaner than the corresponding branching ratios, which are plagued by large end point divergences. We find that the dominant contribution to the uncertainties of these observables stem from the corresponding form factors. The Standard Model estimates for these observables corresponding to the $K^{\ast 0}{\bar{K}}^{\ast 0}$ and $K^0{\bar{K}}^0$ final states are in tension with their respective experimental numbers at the $\sim 2.5\sigma$ level. The pattern of deviations w.r.t these observables as well as the individual branching ratios suggest that a possible explanation might be new physics both in $b\to s$ and $b\to d$ transitions. We find that, taken one at a time, only the Wilson coefficients $C_{4d,s}^{NP}$ and $C_{8gd,s}^{NP}$ can potentially satisfy all the current experimental data on the branching ratios as well as the optimized observables. Furthermore, such observables involving mixed (pseudoscalar-vector) states like $K^{\ast 0}{\bar{K}}^0$ etc show distinctive patterns sensitive to these different new physics explanations.

    hep-phhep-exPoS(2023)·0 citations
12. 12*

    Boosting dark matter searches at muon colliders with Machine Learning: the mono-Higgs channel as a case study

    Mohamed Belfkir🇦🇪 · Adil Jueid🇰🇷 · Salah Nasri🇦🇪

    The search for dark-matter (DM) candidates at high-energy colliders is one of the most promising avenues to understand the nature of this elusive component of the universe. Several searches at the Large Hadron Collider (LHC) have strongly constrained a wide range of simplified models. The combination of the bounds from the LHC with direct-detection experiments exclude the most minimal scalar singlet DM model. To address this, Lepton portal DM models are suitable candidates where DM is predominantly produced at lepton colliders since the DM candidate only interacts with the lepton sector through a mediator that carries a lepton number. In this work, we analyse the production of DM pairs in association with a Higgs boson decaying into two bottom quarks at future muon colliders in the framework of the minimal lepton portal DM model. It is found that the usual cut-based analysis methods fail to probe heavy DM masses for both the resolved (where the decay products of the Higgs boson can be resolved as two well-separated small-$R$ jets) and the merged (where the Higgs boson is clustered as one large-$R$ jet). We have then built a search strategy based on Boosted-Decision Trees (BDTs). We have optimised the hyperparameters of the BDT model to both have a high signal-to-background ratio and to avoid overtraining effects. We have found very important enhancements of the signal significance with respect to the cut-based analysis by factors of $8$--$50$ depending on the regime (resolved or merged) and the benchmark points. Using this BDT model on a one-dimensional parameter space scan we found that future muon colliders with $\sqrt{s}=3$ TeV and $\mathcal{L}=1{\mathrm{ab}}^{-1}$ can exclude DM masses up to $1$ TeV at the $95\%$ CL.

    hep-phPTEP(2023)·18 citations
13. 13*

    Searching for heavy neutral leptons through exotic Higgs decays at the ILC

    Simon Thor🇸🇪 · Masaya Ishino🇯🇵 · Junping Tian🇯🇵

    In this study we investigate the feasibility of detecting heavy neutral leptons ($N_d$) through exotic Higgs decays at the proposed International Linear Collider (ILC), specifically in the channel of $e^{+}{e}^{-}\to qqH$ with $H\to \nu N_d\to \nu lW\to \nu lqq$. Analyses based on full detector simulations of the ILD are performed at the center-of-mass energy of 250 GeV for two different beam polarization schemes with a total integrated luminosity of 2 ${\mathrm{ab}}^{-1}$. A range of heavy neutral lepton masses between the $Z$ boson and Higgs boson masses are studied. The $2\sigma$ significance reach for the joint branching ratio of $BR(H\to \nu N_d)\cdot BR(N_d\to lW)$ is about 0.1\%, nearly independent of the heavy neutral lepton masses, while the $5\sigma$ discovery is possible at a branching ratio of $0.3\%$. Interpreting these results in terms of constraints on the mixing parameters $|{\epsilon }_{id}{|}^2$ between SM neutrinos and the heavy neutral lepton, it is expected to have a factor of 10 improvement from current constraints.

    hep-phhep-exPRD(2024)·3 citations
14. 14*

    Impact of Inclusive Electron Ion Collider Data on Collinear Parton Distributions

    Néstor Armesto🇪🇸 · Thomas Cridge🇩🇪 · Francesco Giuli🇨🇭 · Lucian Harland-Lang🇬🇧 · Paul Newman🇬🇧 · Barak Schmookler🇺🇸 · Robert Thorne🇬🇧 · Katarzyna Wichmann🇩🇪

    A study is presented of the impact of simulated inclusive Electron Ion Collider Deep Inelastic Scattering data on the determination of the proton and nuclear parton distribution functions (PDFs) at next-to-next-to-leading and next-to-leading order in QCD, respectively. The influence on the proton PDFs is evaluated relative to the HERAPDF2.0 set, which uses inclusive HERA data only, and also relative to the global fitting approach of the MSHT20 PDFs. The impact on nuclear PDFs is assessed relative to the EPPS21 global fit and is presented in terms of nuclear modification ratios. For all cases studied, significant improvements in the PDF uncertainties are observed for several parton species. The most striking impact occurs for the nuclear PDFs in general and for the region of high Bjorken $x$ in the proton PDFs, particularly for the valence quark distributions.

    hep-phPRD(2024)·22 citations
15. 15*

    Tetraquark mixing model is superior to meson molecules in explaining two light-meson nonets

    Hungchong Kim🇰🇷 · K.S.Kim🇰🇷

    In this work, we compare the tetraquark mixing model and meson molecules in describing the two physical nonets in the $J^P=0^{+}$ channel, the light nonet [$a_0(980)$, $K_0^{\ast }(700)$, $f_0(500)$, $f_0(980)$] and the heavy nonet [$a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$]. In particular, we focus on whether successful aspects of the tetraquark mixing model that apply to all members of each nonet can be reproduced from a model of meson molecules. By combining two mesons in the lowest-lying pseudoscalar nonet, we construct SU${}_f$(3) molecular nonets that can be tested for the two physical nonets. This molecular approach can make two flavor nonets just as the tetraquark mixing model but this model has some difficulties in describing the universal features of the two nonets %Because of this, this molecular model cannot reproduce successful aspects of the tetraquark mixing model, such as mass splitting between the two nonets, and enhancement or suppression of the coupling strengths of the two nonets into two pseudoscalar mesons. We also compare the fall-apart modes of the tetraquark mixing model and the two-meson modes from the molecular model. A clear distinction can be seen by the two-pion modes in the isovector resonances. The two-pion modes appear in the molecular model, but not in the tetraquark mixing model. The absence of the two-pion modes is supported by the experimental decay modes of the isovector resonances.

    hep-phhep-exnucl-exnucl-thPRD(2023)·3 citations
16. 16*

    Visible in the laboratory and invisible in cosmology: decaying sterile neutrinos

    Kevork N. Abazajian🇺🇸 · Helena García Escudero🇺🇸

    The expansion history and thermal physical process that happened in the early Universe before big bang nucleosynthesis (BBN) remains relatively unconstrained by observations. Low reheating temperature universes with normalcy temperatures of $T_{\mathrm{RH}}\sim 2\mathrm{MeV}$ remain consistent with primordial nucleosynthesis, and accommodate several new physics scenarios that would normally be constrained by high-temperature reheating models, including massive sterile neutrinos. We explore such scenarios' production of keV scale sterile neutrinos and their resulting constraints from cosmological observations. The parameter space for massive sterile neutrinos is much less constrained than in high-$T_{\mathrm{RH}}$ thermal histories, though several cosmological constraints remain. Such parameter space is the target of several current and upcoming laboratory experiments such as TRISTAN (KATRIN), HUNTER, MAGNETO-$\nu$, and PTOLEMY. Cosmological constraints remain stringent for stable keV-scale sterile neutrinos. However, we show that sterile neutrinos with a dark decay to radiation through a $Z^{\prime }$ or a new scalar are largely unconstrained by cosmology. In addition, this mechanism of sterile neutrinos with large mixing may provide a solution to the Hubble tension. We find that keV-scale sterile neutrinos are therefore one of the best probes of the untested pre-BBN era in the early Universe and could be seen in upcoming laboratory experiments.

    hep-phastro-ph.COastro-ph.HEPRD(2023)·15 citations
17. 17*

    The framework of the auxiliary group: two birds with one stone

    R. Krishnan🇮🇳

    Flavon models in the literature assume constraints on the components of the vacuum expectation values (vevs) of flavons, and typically, these constraints are not fully determined by the residual symmetry group of the set of vevs. This poses a problem because the general potential of the flavons cannot have a minimum that leads to such constraints unless additional mechanisms involving supersymmetry, extra dimensions etc., are invoked. In this paper, we show that the framework of the auxiliary group naturally results in vevs satisfying the required constraints, and using it, we construct a type-1 seesaw model with two right-handed neutrinos, which predicts the ratio of the light neutrino masses $m_2/m_3=(\sqrt{2}-1)/(\sqrt{2}+1)$ and ${\text{TM}}_1$ mixing with $\sin {\theta }_{13}=\frac{1}{\sqrt{3}}\sin \frac{\pi }{12}$ and $\sin {\delta }_{\text{CP}}=-1$. Our framework posits auxiliary group transformations which act on the flavons but not on the fermions. We construct the general renormalizable potential without invoking additional mechanisms and show that it has a minimum that leads to the required constraints.

    hep-ph2 citations
18. 18*

    Heavy neutral leptons from kaons in effective field theory

    Rebeca Beltrán🇪🇸 · Julian Günther🇩🇪 · Martin Hirsch🇪🇸 · Arsenii Titov🇮🇹 · Zeren Simon Wang🇹🇼

    In the framework of the low-energy effective theory containing in addition to the Standard Model fields heavy neutral leptons (HNLs), we compute the decay rates of neutral and charged kaons into HNLs. We consider both lepton-number-conserving and lepton-number-violating four-fermion operators, taking into account also the contribution of active-heavy neutrino mixing. Assuming that the produced HNLs are long-lived, we perform simulations and calculate the sensitivities of future long-lived-particle (LLP) detectors at the high-luminosity LHC as well as the near detector of the Deep Underground Neutrino Experiment (DUNE-ND) to the considered scenario. When applicable, we also recast the existing bounds on the minimal mixing case obtained by NA62, T2K, and PS191. Our findings show that while the future LHC LLP detectors can probe currently allowed parameter space only in certain benchmark scenarios, DUNE-ND should be sensitive to parameter space beyond the current bounds in almost all the benchmark scenarios and for some of the effective operators considered it can even probe new-physics scales in excess of 3000 TeV.

    hep-phPRD(2024)·13 citations
19. 19*

    Rising Through the Ranks: Flavor Hierarchies from a Gauged SU(2) Symmetry

    Admir Greljo🇨🇭 · Anders Eller Thomsen🇨🇭

    We propose an economical model to address the mass hierarchies of quarks and charged leptons. The light generations of the left-handed fermions form doublets under an $\mathrm{SU}(2)$ flavor symmetry, which is gauged. The generational hierarchies emerge from three independent rank-one contributions to the Yukawa matrices: one is a renormalizable contribution, the second is suppressed by a mass ratio, and the last by an additional loop factor. The model is renormalizable and features only a handful of new fields and is remarkably simple compared to typical completions of gauged flavor symmetries or Froggatt-Nielsen. The model has a rich phenomenology, and we highlight promising signatures, especially in the context of $K$ and $B$ meson physics. This includes an interpretation of the latest $B^{+}\to K^{+}\nu \bar{\nu }$ measurement from Belle II.

    hep-phEPJC(2024)·36 citations
20. 20*

    Variance Reduction via Simultaneous Importance Sampling and Control Variates Techniques Using Vegas

    Prasanth Shyamsundar🇺🇸 · Jacob L. Scott🇺🇸 · Stephen Mrenna🇺🇸 · Konstantin T. Matchev🇺🇸 · Kyoungchul Kong🇺🇸

    Monte Carlo (MC) integration is an important calculational technique in the physical sciences. Practical considerations require that the calculations are performed as accurately as possible for a given set of computational resources. To improve the accuracy of MC integration, a number of useful variance reduction algorithms have been developed, including importance sampling and control variates. In this work, we demonstrate how these two methods can be applied simultaneously, thus combining their benefits. We provide a python wrapper, named CoVVVR, which implements our approach in the Vegas program. The improvements are quantified with several benchmark examples from the literature.

    hep-phphysics.data-anSciPost Phys.Codeb.(2024)·3 citations
21. 21*

    Median Statistics Estimate of the Distance to M87

    Nicholas Rackers · Sofia Splawska · Bharat Ratra🇺🇸

    de Grijs and Bono compiled 211 independent measurements of the distance to galaxy M87 in the Virgo cluster from 15 different tracers and reported the arithmetic mean of a subset of this compilation as the best estimate of the distance. We compute three different central estimates -- the arithmetic mean, weighted mean, and the median -- and corresponding statistical uncertainty for the full data set as well as two sub-compilations. We find that for all three central estimates the error distributions show that the data sets are significantly non-Gaussian. As a result, we conclude that that the median is the most reliable of the three central estimates, as median statistics does not assume Gaussianity. We use median statistics to determine the systematic error on the distance by analyzing the scatter in the 15 tracer subgroup distances. From the 211 distance measurements, we recommend a summary M87 distance modulus of $31.08_{-0.05}^{+0.04}$ (statistical) ${}_{-0.06}^{+0.04}$ (systematic) mag, or combining the two errors in quadrature $31.08_{-0.08}^{+0.06}$ mag, rounded to $16.4_{-0.6}^{+0.5}$ Mpc, all at $68.27\%$ significance.

    ↳ astro-ph.COgr-qchep-phPubl.Astron.Soc.Pac.(2024)·3 citations
22. 22*

    Effects of electrons on nuclear clock transition frequency in ${}^{229}$Th ions

    V. A. Dzuba🇦🇺 · V. V. Flambaum🇦🇺

    We perform calculations of the energy shift of the nuclear clock transition frequency ${}^{229}$Th as a function of the number of electrons in Th ion. We demonstrate that the dependence of the nuclear frequency on electron configuration is significant. E.g., removing one electron from the atom leads to relative shift of the nuclear frequency $\sim 10^{-7}$, which is twelve orders of magnitude larger than expected relative uncertainty of the nuclear clock transition frequency ($\sim 10^{-19}$). This leads to difference of the nuclear clock frequencies in Th~IV, Th~III, Th~II and Th~I. The relative change of the nuclear frequency between neutral Th and its bare nucleus is 1\%. We also calculate the field shift constants for isotopic and isomeric shifts of atomic electron transitions in Th ions.

    ↳ physics.atom-phhep-phnucl-thPRL(2023)·13 citations
23. 23*

    Critical Point from Shock Waves Solution in Relativistic Anisotropic Hydrodynamics

    Aleksandr Kovalenko🇷🇺

    Solutions of shock waves in anisotropic relativistic hydrodynamics in the absence of refraction of the flow passing through the shock wave are considered. The existence of a critical value of the anisotropy parameter is shown. This value is the upper limit below which an adequate description of shock waves is possible. Shock wave solutions also provide a mechanism for system isotropization.

    ↳ nucl-thhep-phBull.Lebedev Phys.Inst.(2023)·1 citation
24. 24*

    Generalized early dark energy and its cosmological consequences

    Tatsuki Kodama🇯🇵 · Takumi Shinohara🇯🇵 · Tomo Takahashi🇯🇵

    We investigate cosmological consequences of a generalized early dark energy (EDE) model where a scalar field behaves as dark energy at various cosmological epochs for a broad range of parameters such as the energy scale and the initial field value. We consider power-law and axion-type potentials for such an EDE field and study how it affects the cosmological evolution. We show that gravitational wave background can be significantly enhanced to be detected in future observations such as LISA and DECIGO in some parameter space. Implications of the EDE model are also discussed for a scenario where a blue-tilted inflationary tensor power spectrum can explain the recent NANOGrav 15-year signal. We argue that the bounds on the reheating temperature can be relaxed compared to the case of the standard thermal history.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·4 citations
25. 25*

    Prospects for searches of $b\to s\nu \bar{\nu }$ decays at FCC-ee

    Yasmine Amhis🇫🇷 · Matthew Kenzie🇬🇧 · Méril Reboud🇬🇧 · Aidan R. Wiederhold🇬🇧

    We investigate the physics reach and potential for the study of various decays involving a $b\to s\nu \bar{\nu }$ transition at the Future Circular Collider running electron-positron collisions at the $Z$-pole (FCC-ee). Signal and background candidates, which involve inclusive $Z$ contributions from $b\bar{b}$, $c\bar{c}$ and $uds$ final states, are simulated for a proposed multi-purpose detector. Signal candidates are selected using two Boosted Decision Tree algorithms. We determine expected relative sensitivities of $0.53\%$, $1.20\%$, $3.37\%$ and $9.86\%$ for the branching fractions of the $B^0\to K^{\ast 0}\nu \bar{\nu }$, $B_s^0\to \varphi \nu \bar{\nu }$, $B^0\to K_S^0\nu \bar{\nu }$ and ${\Lambda }_b^0\to {\Lambda }^0\nu \bar{\nu }$ decays, respectively. In addition, we investigate the impact of detector design choices related to particle-identification and vertex resolution. The phenomenological impact of such measurements on the extraction of Standard Model and new physics parameters is also studied.

    ↳ hep-exhep-phJHEP(2024)·41 citations
26. 26*

    Weyl conformal geometry vs Weyl anomaly

    D. M. Ghilencea🇷🇴

    Weyl conformal geometry is a gauge theory of scale invariance that naturally brings together the Standard Model (SM) and Einstein gravity. The SM embedding in this geometry is possible without new degrees of freedom beyond SM and Weyl geometry, while Einstein gravity is generated by the broken phase of this symmetry. This follows a Stueckelberg breaking mechanism in which the Weyl gauge boson becomes massive and decouples, as discussed in the past (arXiv:1812.08613, 1904.06596, 2104.15118). However, Weyl anomaly could break explicitly this gauge symmetry, hence we study it in Weyl geometry. We first note that in Weyl geometry {\it metricity} can be restored with respect to a new differential operator ($\hat{\nabla }$) that also enforces a Weyl-covariant formulation. This leads to a metric-like Weyl gauge invariant formalism that enables one to do quantum calculations directly in Weyl geometry, rather than use a Riemannian (metric) geometry picture. The result is the Weyl-covariance in $d$ dimensions of all geometric operators ($\hat{R}$, etc) {\it and} of their derivatives (${\hat{\nabla }}_{\mu }\hat{R}$, etc), including the Euler-Gauss-Bonnet term. A natural, Weyl-invariant dimensional regularisation of quantum corrections exists and Weyl gauge symmetry is then maintained and manifest at the quantum level, in $d$ dimensions. This is related to a non-trivial current of this symmetry, the divergence of which cancels the trace of the energy-momentum tensor. The "usual" Weyl anomaly and Riemannian geometry are recovered in the (spontaneously) broken phase. The relation to holographic Weyl anomaly is discussed.

    ↳ hep-thgr-qchep-phJHEP(2023)·31 citations
27. 27*

    Axion Curvaton Model for the Gravitational Waves Observed by Pulsar Timing Arrays

    Keisuke Inomata🇺🇸 · Masahiro Kawasaki🇯🇵 · Kyohei Mukaida🇯🇵 · Tsutomu T. Yanagida🇯🇵

    The stochastic gravitational wave background (SGWB) recently detected by the PTA collaborations could be the gravitational waves (GWs) induced by curvature perturbations. However, primordial black holes (PBHs) might be overproduced if the SGWB is explained by the GWs induced by the curvature perturbations that follow the Gaussian distribution. This motivates models associated with the non-Gaussianity of the curvature perturbations that suppress the PBH production rate. In this work, we show that the axion curvaton model can produce the curvature perturbations that induce GWs for the detected SGWB while preventing the PBH overproduction with the non-Gaussianity.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·42 citations
28. 28*

    Unveiling dark forces with measurements of the Large Scale Structure of the Universe

    Salvatore Bottaro🇮🇱 · Emanuele Castorina🇮🇹 · Marco Costa🇮🇹 · Diego Redigolo🇮🇹 · Ennio Salvioni🇮🇹

    Cosmology offers opportunities to test Dark Matter independently of its interactions with the Standard Model. We study the imprints of long-range forces acting solely in the dark sector on the distribution of galaxies, the so-called Large Scale Structure (LSS). We derive the strongest constraint on such forces from a combination of Planck and BOSS data. Along the way we consistently develop, for the first time, the Effective Field Theory of LSS in the presence of new dynamics in the dark sector. We forecast that future surveys will improve the current bound by an order of magnitude.

    ↳ astro-ph.COhep-phPRL(2024)·42 citations
29. 29*

    Signature of Einstein-Cartan theory

    Bruno Arderucio Costa🇲🇽 · Yuri Bonder🇲🇽

    We study the physical effects of torsion as predicted by the Einstein-Cartan theory in the test particle approximation and the non-relativist limit. We first present the corresponding non-relativistic Hamiltonian for a 2-spinor. Then, we solve an idealized reflection and transmission problem for a non-relativistic spin-$\frac{1}{2}$ beam travelling across a spin-polarized target. We identify deviations in the spin polarizations of the reflected and transmitted as observables capable of distinguishing Einstein-Cartan from standard general relativity. If measured, this effect would constitute compelling evidence for the presence of spacetime torsion.

    ↳ gr-qchep-phPLB(2024)·9 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.