Thu·Jun 30, 2022Thursday·June 30, 2022

1. 01*

   Unveiling Time-Varying Signals of Ultralight Bosonic Dark Matter at Collider and Beam Dump Experiments

   Jinhui Guo🇨🇳 · Yuxuan He🇨🇳 · Jia Liu🇨🇳 · Xiao-Ping Wang🇨🇳 · Ke-Pan Xie🇺🇸

   The ultralight boson represents a promising dark matter candidate exhibiting unique wave-like behaviors. These properties could transfer to the dark mediator, such as the kinetic mixing dark photon, which can be a link between the dark and Standard Model sectors, resulting in periodic oscillations of its mass. We propose a method to detect ultralight dark matter using dark mediators in collider and beam dump experiments, distinguishing it from conventional atomic, molecular, and optical methods. The time-varying nature of dark mediator mass exhibits a double-peak spectrum, reducing traditional constraints by 1 to 2 orders of magnitude, due to decreased luminosity exposure in each resonant mass bin. To enhance sensitivity, we utilize event time-stamps in the CMS Open Data and demonstrate that this technique boosts sensitivity by approximately one order of magnitude compared to the time-blind method. Moreover, it proves effective in detecting the invisible decay of the dark mediator.

   hep-phhep-exCommun.Phys.(2023)·8 citations
2. 02*

   A Normalized Autoencoder for LHC Triggers

   Barry M. Dillon (1)🇩🇪 · Luigi Favaro (1)🇩🇪 · Tilman Plehn (1)🇩🇪 · Peter Sorrenson (2)🇩🇪 · Michael Krämer (3) ((1) Institut für Theoretische Physik, Universität Heidelberg, Germany, (2) Heidelberg Collaboratory for Image Processing, Universität Heidelberg, Germany, (3) Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, Germany)🇩🇪

   Autoencoders are an effective analysis tool for the LHC, as they represent one of its main goal of finding physics beyond the Standard Model. The key challenge is that out-of-distribution anomaly searches based on the compressibility of features do not apply to the LHC, while existing density-based searches lack performance. We present the first autoencoder which identifies anomalous jets symmetrically in the directions of higher and lower complexity. The normalized autoencoder combines a standard bottleneck architecture with a well-defined probabilistic description. It works better than all available autoencoders for top vs QCD jets and reliably identifies different dark-jet signals.

   hep-phSciPost Phys.Core(2023)·47 citations
3. 03*

   Effect of thermal gluon absorption and medium fluctuations on heavy flavour nuclear modification factor at RHIC and LHC energies

   Ashik Ikbal Sheikh🇺🇸

   The presence of thermal gluons reduces the stimulated gluon emission off a heavy quark propagating in the quark-gluon plasma (QGP) while absorption causes reduction of the radiative energy loss. On the other hand, the chromo-electromagnetic field fluctuations present in the QGP lead to collisional energy gain of the heavy quark. The net effect of the thermal gluon absorption and field fluctuations is a reduction of the total energy loss of the heavy quark, prominent at the lower momenta. We consider both kind of the energy gains along with the usual losses, and compute the nuclear modification factor ($R_{AA}$) of heavy mesons, viz., $D$ and $B$ mesons. The calculations have been compared with the experimental measurements in Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV from STAR and PHENIX experiments at the RHIC and Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV and $5.02$ TeV from CMS and ALICE experiments at the LHC. We find a significant effect of the total energy gain due to thermal gluon absorption and field fluctuations on heavy flavour suppression, especially at the lower transverse momenta.

   hep-phnucl-exnucl-thEPJA(2021)·1 citation
4. 04*

   Cosmic Neutrinos as a Window to Departures from Special Relativity

   J.M. Carmona🇪🇸 · J.L. Cortes🇪🇸 · J.J. Relancio🇪🇸 · M.A. Reyes🇪🇸

   We review the peculiarities that make neutrino a very special cosmic messenger in high-energy astrophysics, and, in particular, to provide possible indications of deviations from special relativity, as it is suggested theoretically by quantum gravity models. In this respect, we examine the effects that one could expect in the production, propagation, and detection of neutrinos, not only in the well-studied scenario of Lorentz Invariance Violation, but also in models which maintain, but deform, the relativity principle, such as those considered in the framework of Doubly Special Relativity. We discuss the challenges and the promising future prospects offered by this phenomenological window to physics beyond special relativity.

   hep-phastro-ph.HESymmetry(2022)·2 citations
5. 05*

   ALP Dark Matter from Kinetic Fragmentation: Opening up the Parameter Window

   Cem Eröncel🇩🇪 · Ryosuke Sato🇯🇵 · Geraldine Servant🇩🇪 · Philip Sørensen🇩🇪

   The main mechanism responsible for Axion-Like-Particle (ALP) production in the early universe is the so-called misalignment mechanism. Three regimes have been investigated in this context: standard misalignment, large misalignment and kinetic misalignment. The latter applies if the axion inherits a large initial velocity in the early universe, such that the field rolls through many wiggles during its evolution, before it gets trapped in one minimum. This largely opens the region of parameter space for ALP dark matter towards higher values for the axion-photon coupling, which can be probed by the whole set of next decade's upcoming experiments. In fact, almost the entire parameter space in the [mass, decay constant] plane can now accommodate dark matter. In this paper, we show that in kinetic misalignment, the axion field is almost always entirely fragmented, meaning that the energy density of the homogeneous field is redistributed over higher-mode axions. We present a general model-independent analytical description of kinetic fragmentation, including discussion of the modified initial conditions for the mode functions due to the axion's initial velocity, and how they impact the growth of the adiabatic fluctuations. We calculate precisely the parameter regions corresponding respectively to standard misalignment, kinetic misalignment with weak fragmentation, fragmentation after trapping and fragmentation before trapping. While axion fragmentation can impact the precise determination of the relic abundance, another main observational implication is the formation of much denser compact axion halos, that is described in a companion paper. We also point out a new gravitational-wave signature that arises in the large misalignment regime with complete fragmentation and could be seen in measurements of $\mu$ distortions in the Cosmic Microwave Background.

   hep-phastro-ph.COJCAP(2022)·85 citations
6. 06*

   On validity of different PDFs sets using the proton $k_t$-factorization structure functions and the Gaussian $k_t$-dependence of KMR UPDFs

   Z. Badieian Baghsiyahi🇮🇷 · Majid Modarres🇮🇷 · Ramin Kord Valeshabadi🇮🇷

   In this work, we discuss: (i) The ratios of different parton distribution functions (PDFs), i.e., MMHT2014, CJ15, CTEQ6l1, HERAPDF15, MSTW2008, HERAPDF20 and MSHT20, and the corresponding Kimber-Martin-Ryskin (KMR) unintegrated parton distribution functions (UPDFs) sets versus the hard scale $Q^2$, to find out the sensibility of the KMR UPDFs with respect to the input PDFs sets. It is shown that there is not much difference between the different input-PDFs or corresponding UPDFs sets ratios. (ii) Then, the dependence of proton $k_t$-factorization structure functions on the different UPDFs sets which can use the above PDFs sets as input, are presented. The results are compared with the experimental data of ZEUS, NMC and H1+ZEUS at the hard scale $Q^2=27$ and $90$ $Ge{V}^2$, and a reasonable agreement is found, considering different input PDFs sets. (iii) Furthermore, by fitting a Gaussian function, which depends on the transverse momentum $k_t$, to the KMR UPDFs and averaging over $x$ (the fractional parton momentum), we obtain the average transverse momentum, $<k_t^2>$, in the scale range $Q^2=2.4-1.44\times 10^4$ $Ge{V}^2$, which is in agreement with the other groups predictions, $0.25-0.44$ $Ge{V}^2$ at $Q^2=2.4$ $Ge{V}^2$. (iv) Finally we explore the average transverse momentum for which, the results of proton structure function with the KMR UPDFs and that of the Gaussian $k_t$-dependent, are consistent to each other. Through the above report, at each step the parton branching (PB) UPDFs, i.e., the transverse momentum dependent PDFs (PB TMDPDFs) are considered for comparisons with the corresponding KMR UPDFs output.

   hep-phhep-exhep-thEPJC(2022)·4 citations
7. 07*

   Possibly heteroclite electron Yukawa coupling and small $△a_{\mu }$ in a hidden Abelian gauge model for neutrino masses

   We-Fu Chang🇹🇼 · Shih-Hsien Kuo🇹🇼

   We attempt to simultaneously explain the neutrino oscillation data and the observed $(g-2{)}_{e,\mu }$ in a hidden gauge $U(1{)}_X$ model where all the Standard Model(SM) fields are $U(1{)}_X$ singlets. The minimal version of this model calls for four exotic scalars and two pairs of vector fermions, and all are charged under $U(1{)}_X$. We carefully consider the experimental limits on charge lepton flavor violation without assuming any flavor symmetry and explore the viable model parameter space. The model can accommodate the neutrino oscillation data for both the normal and the inverted mass ordering while explaining the central value of $△a_e$ by adopting the fine structure constant determined by using either Cesium or Rubidium atoms. However, mainly constrained by the current experimental bound on $\mathcal{B}(\tau \to \mu \gamma )$, this model predicts $△a_{\mu }<5.5(8.0)\times 10^{-10}$ for the normal(inverted) neutrino ordering. Moreover, while the muon Yukawa coupling is close to the SM one, we find the magnitude of the electron Yukawa coupling could be one order of magnitude larger than the SM prediction. This abnormal electron Yukawa could be probed in the future FCC-ee collider and plays an essential role in testing flavor physics.

   hep-phhep-ex4 citations
8. 08*

   Cross Section Calculations in Theories of Self-Interacting Dark Matter

   Sudhakantha Girmohanta🇺🇸 · Robert Shrock🇺🇸

   We study an asymmetric dark matter model with self-interacting dark matter consisting of a Dirac fermion $\chi$ coupled to a scalar or vector mediator, such that the reaction $\chi +\chi \to \chi +\chi$ is well described by perturbation theory. We compute the scattering cross section $\sigma$, the transfer cross section ${\sigma }_T$, and the viscosity cross section ${\sigma }_V$ for this reaction. As one part of our study, we give analytic and numerical comparisons of results obtained with the inclusion of both $t$-channel and $u$-channel exchanges and results obtained in an approximation that has often been used in the literature that includes only the $t$-channel contribution. The velocity dependences of these cross sections are studied in detail and shown to be in accord with observational data.

   hep-phastro-ph.COastro-ph.GAhep-ex+1PRD(2022)·35 citations
9. 09*

   Quantum Chromodynamics Resolution of the ATOMKI Anomaly in ${}^4\mathrm{He}$ Nuclear Transitions

   Valery Kubarovsky🇺🇸 · Jennifer Rittenhouse West🇺🇸 · Stanley J. Brodsky🇺🇸

   Observations of anomalous angular correlations in electron-positron pairs produced from excited states of ${}^4$He, ${}^8$Be and ${}^{12}$C nuclei have been suggested as due to the creation and subsequent decay of a new light particle of mass $\sim$17 MeV. In this work, we investigate the possibility that the source of the observed signals is a set of new excitation channels created by the 12-quark hidden-color Fock state within the ${}^4\mathrm{He}$ nuclear wavefunction dubbed the ``hexadiquark.'' We calculate the invariant $e^{+}{e}^{-}$ mass spectrum for the electromagnetic transition from a new excitation of ${}^4$He, estimating its differential and total decay width. We find that we can fit the shape of the anomalous signal with the QCD Fock state at excitation energy ${\mathrm{E}}^{\ast }=17.9\pm 1$ MeV and a Gaussian form factor for the electromagnetic decay. We address the physical issues with the fit parameters using properties of the hexadiquark state, in particular the three weakly repulsive $6_{\mathrm{C}}$ interactions of $\mathrm{SU}(3{)}_{\mathrm{C}}$ between diquark pairs. Experimental tests of our model are described in detail. In light of this work, we emphasize the need for independent experimental confirmation or refutation of the ATOMKI results as well as dedicated experiments to search for the proposed new excitations of ${}^4\mathrm{He}$ and other $\alpha$-cluster nuclei.

   hep-phnucl-exnucl-thPRC(2025)·16 citations
10. 10*

    A Unitarity Approach to Two-Loop All-Plus Rational Terms

    David A. Kosower🇫🇷 · Sebastian Pögel🇩🇪

    We present a calculation of the rational terms in two-loop all-plus gluon amplitudes using $D$-dimensional unitarity. We use a conjecture of separability of the two loops, and then a simple generalization of one-loop $D$-dimensional unitarity to perform calculations. We compute the four- and five-point rational terms analytically, and the six- and seven-point ones numerically. We find agreement with previous calculations of Dalgleish, Dunbar, Godwin, Jehu, Perkins, and Strong. For a special subleading-color amplitude, we compute the eight- and nine-point results numerically, and find agreement with an all-$n$ conjecture of Dunbar, Perkins, and Strong.

    hep-phhep-th13 citations
11. 11*

    Theoretical study on the contributions of $\omega$ meson to the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ and $J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0$ decays

    Hao-Nan Wang🇨🇳 · Qian Wang🇨🇳 · Ju-Jun Xie🇨🇳

    With the newly measurements of $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ from LHCb Collaboration, in addition to the dominant contribution from the ${\rho }^0$ meson, we perform a theoretical study on the contribution of $\omega$ meson in the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ and $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0$ processes. It is found that the recent experimental measurements on the ${\pi }^{+}{\pi }^{-}$ invariant mass distributions can be well reproduced, and the ratio of the couplings between $X(3872)\to J/\psi {\rho }^0$ and $X(3872)\to J/\psi \omega$ is also evaluated. Within the parameters extracted from the ${\pi }^{+}{\pi }^{-}$ invariant mass distributions of the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ process, the branching fractions of the $X(3872)\to J/\psi \omega$ channel relative to that of the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0$ channel and the ${\pi }^{+}{\pi }^{-}{\pi }^0$ invariant mass distributions of the $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0$ decay are calculated, which gives a hint for the further high-statistic experiment.

    hep-phhep-exnucl-exnucl-thPRD(2022)·7 citations
12. 12*

    The spatial string tension and the nonperturbative Debye mass from the Field Correlator Method

    Yu.A.Simonov🇷🇺

    The phenomenon of the almost linear growth of the square root of spatial string tension $\sqrt{{\sigma }_s(T)}=c_{\sigma }{g}^{2}T$ and of the Debye mass $m_D(T)$ was found both in lattice and in theory, based on the Field Correlator Method (FCM). In the latter the string tension (both spatial and colorelectric) is expressed as an integral of the two gluon Green's function calculated with the same string tension: $\sigma =\int G_{\sigma }^{(2g)}$. This relation allows to check the selfconsistency of the theory and at high T it allows also to calculate $c_{\sigma }$ and hence ${\sigma }_s$. We calculate below in the paper the corresponding coefficients $c_{\sigma }$ and $c_D$ numerically in the FCM method and compare the results with lattice data finding a good agreement. This justifies the use of the FCM in the space-like region and in high T thermodynamics without extra parameters.

    hep-phPhys.Atom.Nucl.(2022)·6 citations
13. 13*

    Anomalous Higgs boson couplings in weak boson fusion production at NNLO in QCD

    Konstantin Asteriadis🇺🇸 · Fabrizio Caola🇬🇧 · Kirill Melnikov🇩🇪 · Raoul Röntsch🇮🇹

    The production of Higgs bosons in weak boson fusion has the second largest cross section among Higgs-production processes at the LHC. As such, this process plays an important role in detailed studies of Higgs interactions with vector bosons. In this paper we extend the available description of Higgs boson production in weak boson fusion by considering anomalous $HVV$ interactions and NNLO QCD radiative corrections at the same time. We find that, while leading order QCD predictions are too uncertain to allow for detailed studies of the anomalous couplings, NLO QCD results are sufficiently precise, most of the time. The NNLO QCD corrections alter the NLO QCD predictions only marginally, but their availability enhances the credibility of conclusions based on NLO QCD computations.

    hep-phPRD(2023)·5 citations
14. 14*

    Implications of the muon anomalous magnetic moment for the LHC and MUonE

    Akanksha Bhardwaj🇬🇧 · Christoph Englert🇬🇧 · Panagiotis Stylianou🇬🇧

    We consider the anomalous magnetic moment of the muon $a_{\mu }$, which shows a significant deviation from the Standard Model expectation given the recent measurements at Fermilab and BNL. We focus on Standard Model Effective Field Theory (SMEFT) with the aim to identify avenues for the upcoming LHC runs and future experiments such as MUonE. To this end, we include radiative effects to $a_{\mu }$ in SMEFT to connect the muon anomaly to potentially interesting searches at the LHC, specifically Higgs decays into muon pairs and such decays with resolved photons. Our investigation shows that similar to results for concrete UV extensions of the Standard Model, the Fermilab/BNL result can indicate strong coupling within the EFT framework and $a_{\mu }$ is increasingly sensitive to a single operator direction for high scale UV completions. In such cases, there is some complementarity between expected future experimental improvements, yet with considerable statistical challenges to match the precision provided by the recent $a_{\mu }$ measurement.

    hep-phhep-exPRD(2022)·10 citations
15. 15*

    NNLO study of top-quark mass renormalization scheme uncertainties in Higgs boson production

    Javier Mazzitelli🇩🇪

    The ambiguity in the choice of a renormalization scheme and scale for the top-quark mass leads to an additional source of theoretical uncertainty in the calculation of the Higgs boson production cross section via gluon fusion. These uncertainties were found to be dominant in the case of off-shell Higgs production at next-to-leading order in QCD for large values of the Higgs virtuality $m_H^{\ast }$. In this work, we study the uncertainties related to the top-quark mass definition up to next-to-next-to-leading order (NNLO) in QCD. We include the full top-quark mass dependence up to three loops in the virtual corrections, and evaluate the real contributions in the soft limit, therefore obtaining the so-called soft-virtual (SV) approximation. We construct NNLO-SV predictions for off-shell Higgs boson production renormalizing the top-quark mass within both the on-shell (OS) and the MSbar schemes, and study in detail the differences between them. While the differences between the two schemes are sizeable, we find that the predictions are always compatible within scale uncertainties. We also observe that the difference between renormalization schemes is largely reduced when increasing the order of the perturbative expansion. We analyze the quality of the convergence of the perturbative series in both schemes, and find that at large invariant masses the MSbar results present much larger corrections than their OS counterparts. We also comment on the more complicated case of Higgs boson pair production.

    hep-phJHEP(2022)·10 citations
16. 16*

    Leptogenesis in $SO(10)$ Models with $A_4$ Modular Symmetry

    Gui-Jun Ding🇨🇳 · Stephen F. King🇬🇧 · Jun-Nan Lu🇨🇳 · Bu-Yao Qu🇨🇳

    We study the prediction for leptogenesis in two renormalizable supersymmetric $SO(10)\times A_4$ modular models in which the neutrino mass is dominantly generated by the type I seesaw mechanism. The evolution of the lepton asymmetries are described in terms of the three-flavored density matrix equations for three heavy Majorana neutrinos, where both vanishing initial condition and thermal initial condition of the right-handed neutrinos are considered. We also present an analytical approximation based on the Boltzmann equations. We find regions of parameter space compatible with the measured fermion masses and mixing parameters as well as the baryon asymmetry of the Universe. The predictions for the light neutrino masses, the effective mass in neutrinoless doble beta decay and the leptonic CP violation phases are discussed.

    hep-phJHEP(2022)·26 citations
17. 17*

    On the polarization of the non-prompt contribution to inclusive J/$\psi$ production in pp collisions

    Pietro Faccioli🇵🇹 · Carlos Lourenço🇨🇭

    Of the J/$\psi$ mesons (inclusively) produced in pp collisions, a big fraction results from B decays, increasing with transverse momentum and exceeding 50\% for $p_{\mathrm{T}}>20$ GeV. These events must be subtracted in measurements of the polarization of prompt J/$\psi$ mesons. While several studies have addressed the $\psi$(2S) and ${\chi }_c$ impact on the determination of the polarization of the directly-produced J/$\psi$ mesons, the theoretical and experimental knowledge of the non-prompt polarization is very poor. Furthermore, non-prompt J/$\psi$ polarization measurements can provide interesting information on quarkonium hadroproduction, complementing the studies of prompt production. We review the method of measuring the polarization of non-prompt J/$\psi$ mesons (produced in decays of unreconstructed B mesons and detected in the dilepton channel), in conditions typical of LHC experiments studying J/$\psi$ production. Realistic model-independent scenarios are validated with data from experiments studying $e^{+}{e}^{-}\to {\rm Y}$(4S) interactions, converted to the high-momentum regime using B differential cross sections measured at the LHC. The non-prompt J/$\psi$ polarization measurements are seen to remain dependent on the event selection criteria, even after correcting for the dilepton acceptance and efficiencies. This implies that reproducible definitions of all relevant analysis choices must be reported with the polarization result, for rigorous comparisons with other measurements and/or theoretical calculations. We also discuss how the non-prompt J/$\psi$ polarization significantly depends on the relative importance of two complementary $\mathrm{B}\to \mathrm{J}/\psi$ decay topologies, two-body (reasonably dominated by singlet production) and multi-body (including octet contributions), providing, hence, valuable information for studies of the charmonium formation mechanisms.

    hep-phJHEP(2022)·6 citations
18. 18*

    Large Neutrino Asymmetry from TeV Scale Leptogenesis

    Debasish Borah🇮🇳 · Arnab Dasgupta🇺🇸

    We study a class of leptogenesis scenarios with decay or scattering being the source of lepton asymmetry, which can not only give rise to the observed baryon asymmetry in the universe but also can leave behind a large remnant neutrino asymmetry. Such large neutrino asymmetry can not only be probed at future cosmic microwave background (CMB) experiments but is also motivating due to its possible role in solving the recently reported anomalies in ${}^4\mathrm{He}$ measurements. Additionally, such large neutrino asymmetry also offers the possibility of cogenesis if dark matter is in the form of a sterile neutrino resonantly produced in the early universe via Shi-Fuller mechanism. Considering $1\to 2,1\to 3$ as well as $2\to 2$ processes to be responsible for generating the asymmetries, we show that only TeV scale leptogenesis preferably of $1\to N(N\ge 3)$ type can generate the required lepton asymmetry around sphaleron temperature while also generating a large neutrino asymmetry $\sim \mathcal{O}(10^{-2})$ by the epoch of the big bang nucleosynthesis. While such low scale leptogenesis can have tantalising detection prospects at laboratory experiments, the indication of a large neutrino asymmetry provides a complementary indirect signature.

    hep-phastro-ph.COPRD(2023)·27 citations
19. 19*

    Anatomy of kaon decays and prospects for lepton flavour universality violation

    G. D'Ambrosio🇮🇹 · A.M. Iyer🇮🇳 · F. Mahmoudi🇫🇷 · S. Neshatpour🇮🇹

    The kaon sector is characterised by several processes which are under active investigation across different experiments. In this work, we present the global picture that emerges from a study of the different decay modes. We begin by revisiting the theoretical component of these decays and providing up-to-date predictions of the Standard Model as well as the corresponding uncertainties. Several new features emerge, in particular for $K_{S,L}\to \mu \bar{\mu }$, and are presented in considerable detail. This offers an ideal platform for extracting the parameter space supported by the existing data. Motivated by possible lepton flavour universality violation in $B$ decays, we investigate such Beyond the Standard Model effects also in rare kaon decays. Without loss of generality, our primary analyses correspond to the paradigm where the Wilson coefficients for operators involving tau leptons are chosen to be equal to that involving the muon, i.e. $\delta C^{\tau }=\delta C^{\mu }$. We conclude by presenting the possible picture that can be achieved towards the end of the run of data accumulation in the planned experiments. This includes assumptions on possible sensitivity goals that the experiments can aim to achieve, in order to extract the kind of physics highlighted in this paper.

    hep-phJHEP(2022)·63 citations
20. 20*

    Feynman parameter integration through differential equations

    Martijn Hidding🇸🇪 · Johann Usovitsch🇨🇭

    We present a new method for numerically computing generic multi-loop Feynman integrals. The method relies on an iterative application of Feynman's trick for combining two propagators. Each application of Feynman's trick introduces a simplified Feynman integral topology which depends on a Feynman parameter that should be integrated over. For each integral family, we set up a system of differential equations which we solve in terms of a piecewise collection of generalized series expansions in the Feynman parameter. These generalized series expansions can be efficiently integrated term by term, and segment by segment. This approach leads to a fully algorithmic method for computing Feynman integrals from differential equations, which does not require the manual determination of boundary conditions. Furthermore, the most complicated topology that appears in the method often has less master integrals than the original one. We illustrate the strength of our method with a five-point two-loop integral family.

    hep-phhep-thPRD(2023)·29 citations
21. 21*

    The f0(1370) controversy from dispersive meson-meson scattering data analyses

    Jose Ramon Pelaez🇪🇸 · Arkaitz Rodas🇺🇸 · Jacobo Ruiz de Elvira🇪🇸

    We establish the existence of the long-debated $f_0(1370)$ resonance in the dispersive analyses of meson-meson scattering data. For this, we present a novel approach using forward dispersion relations, valid for generic inelastic resonances. We find its pole at $(1245\pm 40)-i(300_{-70}^{+30})$ MeV in $\pi \pi$ scattering. We also provide the couplings as well as further checks extrapolating partial-wave dispersion relations or with other continuation methods. A pole at $(1380_{-60}^{+70})-i(220_{-70}^{+80})$ MeV also appears in the $\pi \pi \to K\bar{K}$ data analysis with partial-wave dispersion relations. Despite settling its existence, our model-independent dispersive and analytic methods still show a lingering tension between pole parameters from the $\pi \pi$ and $K\bar{K}$ channels that should be attributed to data.

    hep-phhep-exhep-latnucl-thPRL(2023)·30 citations
22. 22*

    Loop Amplitudes from Precision Networks

    Simon Badger🇮🇹 · Anja Butter🇩🇪 · Michel Luchmann🇩🇪 · Sebastian Pitz🇩🇪 · Tilman Plehn🇩🇪

    Evaluating loop amplitudes is a time-consuming part of LHC event generation. For di-photon production with jets we show that simple, Bayesian networks can learn such amplitudes and model their uncertainties reliably. A boosted training of the Bayesian network further improves the uncertainty estimate and the network precision in critical phase space regions. In general, boosted network training of Bayesian networks allows us to move between fit-like and interpolation-like regimes of network training.

    hep-phSciPost Phys.Core(2023)·56 citations
23. 23*

    Doubly Charged Higgs Boson Production at Hadron Colliders II: A Zee-Babu Case Study

    Richard Ruiz🇵🇱

    Motivated by searches for so-called leptonic scalars at the LHC and the recent measurement of the $W$ boson's mass at the Tevatron, we revisit the phenomenology of the Zee-Babu model for neutrino masses and the ability to differentiate it from the Type II Seesaw model at the LHC. We conclude that this task is much more difficult than previously believed. All inputs equal in the two scenarios, we find that total and differential rates for producing pairs of doubly and singly charged scalars are identical in shape and only differ in normalization. The normalization is given by the ratio of hadronic cross sections and can be unity. Differences in cross sections are small and can be hidden by unknown branching rates. This holds for Drell-Yan, $\gamma \gamma$ fusion, and $gg$ fusion, as well as observables at LO and NLO in QCD. This likeness allows us to reinterpret Run II limits on the Type II Seesaw and estimate projections for the HL-LHC. Using updated neutrino oscillation data, we also find that some collider observables, e.g., lepton flavor-violating branching ratios, are now sufficiently precise to provide a path forward. Other means of discrimination are also discussed. As a byproduct of this work, we report the availability of new Universal \texttt{FeynRules} Object libraries, the \texttt{SM\_ZeeBabu} UFO, that enable fully differential simulations up to NLO+LL(PS) with tool chains employing \texttt{MadGraph5\_aMC@NLO}.

    hep-phhep-exJHEP(2022)·20 citations
24. 24*

    A comparison between the Jordan and Einstein Frames in Brans-Dicke theories with torsion

    R.Gonzalez Quaglia🇲🇽 · Gabriel German🇲🇽

    In recent years, gravitational models motivated by quantum corrections to gravity which introduce higher order terms like $R^2$ or terms in which the Riemann tensor is not symmetric have been studied by several authors in the form of a general Brans-Dicke type model containing the Ricci scalar, the Holst term and the Nieh-Yan invariant. In this paper we focus on the less explored Jordan frame of such theories and in the comparison between both this frame and the Einstein one. Furthermore, we discuss the role of the transformation of the torsion under conformal transformations and show that the transformation proposed in this paper (extended conformal transformation) contains a special case of the projective transformation of the connection used in some of the papers that motivated this work. We discuss the role and advantages of the extended conformal transformation and show that this new approach can have interesting consequences by working with different variables such as the metric and torsion. Moreover, we study the stability of the system via a dynamical analysis in the Jordan frame, this in order to analyze whether or not we have the fixed points that can be later identified as the inflationary attractor and the unstable fixed point where inflation could take place. Finally we study the scale invariant case of the general model in the Jordan frame. We find out that both the scalar spectral index and the tensor-to-scalar ratio are in agreement with the latest Planck results.

    ↳ gr-qcastro-ph.COhep-phhep-thEur.Phys.J.Plus(2023)·11 citations
25. 25*

    Effective field theories of gravity and compact binary dynamics: A Snowmass 2021 whitepaper

    Walter D. Goldberger🇺🇸

    In this whitepaper, I describe modern applications of effective field theory (EFT) techniques to classical and quantum gravity, with relevance to problems in astrophysics and cosmology. As in applications of EFT to high-energy, nuclear, or condensed matter physics, the Wilsonian paradigm based on decoupling of short distance scales via renormalization group evolution remains a powerful organizing principle in the context of gravity. However, the presence of spacetime geometry brings in new elements ( non-trivial time-dependence, cosmological or black hole event horizons) which necessitate the introduction of novel field theoretic methods not usually encountered in applications of EFTs to physics at the energy and intensity frontiers. After a brief overview of recent developments in the application of EFT methods to gravity, I will focus on the EFT description of compact binary dynamics, including an overview of some of its applications to the experimental program in gravitational wave detection at LIGO/VIRGO and other observatories.

    ↳ hep-thgr-qchep-ph67 citations
26. 26*

    Investigating the coalescence-inspired sum rule for light nuclei and hypernuclei in heavy-ion collisions

    Ashik Ikbal Sheikh🇺🇸

    A data-driven idea is presented to test if light nuclei and hypernuclei obey the coalescence-inspired sum rule, i.e., to test if the flow of a light nucleus or hypernucleus is the summed flow of each of its constituents. Here, the mass difference and charge difference among the constituents of light nuclei and hypernuclei are treated appropriately. The idea is applied to the available data for $\sqrt{s_{NN}}=3$ GeV fixed-target Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC), published by the STAR collaboration. It is found that the sum rule for light nuclei is approximately valid near mid-rapidity ($-0.3<y<0$), but there is a clear violation of the sum rule at large rapidity ($y<-0.3$). The Jet AA Microscopic Transport Model (JAM), with baryonic mean-field plus nucleon coalescence, generates a similar pattern as obtained from the experimental data. In the present approach, the rapidity dependence of directed flow of the hypernuclei ${}_{\mathrm{\Lambda }}^3\mathrm{H}$ and ${}_{\mathrm{\Lambda }}^4\mathrm{H}$ is predicted in a model-independent way for $\sqrt{s_{NN}}=3$ GeV Au+Au collisions, which will be explored by ongoing and future measurements from STAR.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2022)·2 citations
27. 27*

    Infrared physics of the 3D SU(2) adjoint Higgs model at the crossover transition

    Lauri Niemi🇫🇮 · Kari Rummukainen🇫🇮 · Riikka Seppä🇫🇮 · David J. Weir🇫🇮

    We study the crossover phase transition of the SU(2) Georgi-Glashow model in three dimensions. In this model, a confining condensate of topological 't Hooft-Polyakov monopoles exists in the Higgs regime. We use lattice Monte Carlo simulations to study the monopole gas across a crossover transition, and demonstrate that gradient flow can be used to renormalize the otherwise divergent monopole number density. The condensation of the monopoles means that the theory admits also a massive photon-like excitation. We show that the renormalized monopole number density is approximately proportional to the square of the photon mass, in agreement with semiclassical results. Our results give insight into behaviour of the Higgs regime near crossover, which has boarder implications for beyond the Standard Model theories containing adjoint scalar fields.

    ↳ hep-lathep-phJHEP(2023)·15 citations
28. 28*

    Spectral and transport properties from lattice QCD

    Olaf Kaczmarek🇩🇪 · Hai-Tao Shu🇩🇪

    In these lecture notes we will discuss recent progress in extracting spectral and transport properties from lattice QCD. We will focus on results of probes of the thermal QCD medium as well as transport coefficients which are important ingredients for hydrodynamic and transport models that describe the evolution of the produced medium. These include electromagnetic probes, like the rates of emitted photons and dileptons, quarkonium spectral functions as well as transport coefficients like the electrical conductivity or heavy flavor diffusion coefficients of the quark gluon plasma (QGP). All these real time quantities are encoded in the vector meson spectral function. A direct determination of the spectral functions is not possible in Euclidean lattice QCD calculations but they can be analytically continued from imaginary to real time. Therefore it is possible to relate the spectral function to the corresponding Euclidean correlation functions. In the following sections we will discuss the procedure to determine the required correlation functions and the extraction of the spectral functions from lattice QCD correlators. We will illustrate the concepts and methods to obtain spectral functions and related physical observables from continuum extrapolated correlation functions. We will focus here on results obtained from continuum extrapolated lattice correlation functions, which requires large and fine lattices, which so far was only possible in quenched approximation. We will only give a brief introduction to lattice QCD and refer to the textbooks [1,2,3,4] and lecture notes [5] for more detailed introductions to lattice field theory. For the topics addressed in this lecture note we also like to refer to the overview articles on QCD thermodynamics and the QCD phase transition [5,6,7] and quarkonium in extreme conditions [8].

    ↳ hep-lathep-phnucl-thLect.Notes Phys.(2022)·13 citations
29. 29*

    Mass Perturbation Theory in the 2-Flavor Schwinger Model with Opposite Masses

    Howard Georgi🇺🇸

    I discuss the 2-flavor Schwinger model with $\theta =0$ and small equal and opposite fermion masses (or $\theta =\pi$ with equal masses). The massless model has an unparticle sector with unbroken conformal symmetry. I argue that this special mass term modifies the conformal sector without breaking the conformal symmetry. I show in detail how mass-perturbation-theory works for correlators of flavor-diagonal fermion scalar bilinears. The result provides quantitative evidence that the theory has no mass gap for small non-zero fermion masses. The massive fermions are bound into conformally invariant unparticle stuff. I show how the long-distance conformal symmetry is maintained when small fermion masses are turned on and calculate the relevant scaling dimensions for small mass. I calculate the corrections to the 2- and 4-point functions of the fermion-bilinear scalars to leading order in perturbation theory in the fermion mass and describe a straightforward procedure to extend the calculation to all higher scalar correlators. I hope that this model as a useful and non-trivial example of unparticle physics, a sector with unbroken conformal symmetry coupled to interacting massive particles, in which we can analyze the particle physics in a consistent approximation.

    ↳ hep-thhep-phJHEP(2022)·8 citations
30. 30*

    Gravitational wave production from preheating with trilinear interactions

    Catarina Cosme🇪🇸 · Daniel G. Figueroa🇪🇸 · Nicolas Loayza🇪🇸

    We investigate the production of gravitational waves (GWs) during preheating with monomial/polynomial inflationary potentials, considering a trilinear coupling $\varphi {\chi }^2$ between a daughter field $\chi$ and the inflaton $\varphi$. For sufficiently large couplings, the trilinear interaction leads to an exponential production of $\chi$ particles, and as a result, a large stochastic GW background (SGWB) is generated throughout the process. We study the linear and non-linear dynamics of preheating with lattice simulations, following the production of GWs through all relevant stages. We find that large couplings lead to SGWBs with a large amplitude today, of the order of $h^2{\Omega }_{\mathrm{GW}}^{(0)}\simeq 5\cdot 10^{-9}$. These backgrounds are however peaked at high frequencies $f_{\mathrm{p}}\sim 10^6-10^8$ Hz, which makes them undetectable by current/planned GW observatories. As the amount of GWs produced is in any case remarkable, we discuss the prospects for probing the SGWB indirectly by using constraints on the effective number of relativistic species in the universe $\Delta N_{\mathrm{eff}}$.

    ↳ astro-ph.COhep-phJCAP(2023)·34 citations
31. 31*

    Two-photon exchange in (muonic) deuterium at N3LO in pionless effective field theory

    Vadim Lensky (JGU Mainz)🇩🇪 · Franziska Hagelstein (JGU Mainz and PSI Villigen)🇩🇪 · Vladimir Pascalutsa (JGU Mainz)🇩🇪

    We present a study of the two-photon-exchange ($2\gamma$-exchange) corrections to the $S$-levels in muonic ($\mu$D) and ordinary (D) deuterium within the pionless effective field theory (pionless EFT). Our calculation proceeds up to next-to-next-to-next-to-leading order (N3LO) in the pionless EFT expansion. The only unknown low-energy constant entering the calculation at this order corresponds to the coupling of a longitudinal photon to the nucleon-nucleon system. To minimise its correlation with the deuteron charge radius, it is extracted using the information about the hydrogen-deuterium isotope shift. We find the elastic $2\gamma$-exchange contribution in $\mu$D larger by several standard deviations than obtained in other recent calculations. This discrepancy ameliorates the mismatch between theory and experiment on the size of $2\gamma$-exchange effects, and is attributed to the properties of the deuteron elastic charge form factor parametrisation used to evaluate the elastic contribution. We identify a correlation between the deuteron charge and Friar radii, which can help one to judge how well a form factor parametrisation describes the low-virtuality properties of the deuteron. We also evaluate the higher-order $2\gamma$-exchange contributions in $\mu$D, generated by the single-nucleon structure and expected to be the most important terms beyond N3LO. The uncertainty of the theoretical result is dominated by the truncation of the pionless EFT series and is quantified using a Bayesian approach. The resulting extractions of the deuteron charge radius from the $\mu$D Lamb shift, the $2S-1S$ transition in D, and the $2S-1S$ hydrogen-deuterium isotope shift, with the respective $2\gamma$-exchange effects evaluated in a unified pionless EFT approach, are in perfect agreement.

    ↳ nucl-thhep-phnucl-exphysics.atom-phEPJA(2022)·6 citations
32. 32*

    Galactic Cosmic-Ray Propagation in the Inner Heliosphere: Improved Force-Field Model

    Jung-Tsung Li🇺🇸 · John F. Beacom🇺🇸 · Annika H. G. Peter🇺🇸

    A key goal of heliophysics is to understand how cosmic rays propagate in the solar system's complex, dynamic environment. One observable is solar modulation, i.e., how the flux and spectrum of cosmic rays changes as they propagate inward. We construct an improved force-field model, taking advantage of new measurements of magnetic power spectral density by Parker Solar Probe to predict solar modulation within the Earth's orbit. We find that modulation of cosmic rays between the Earth and Sun is modest, at least at solar minimum and in the ecliptic plane. Our results agree much better with the limited data on cosmic-ray radial gradients within Earth's orbit than past treatments of the force-field model. Our predictions can be tested with forthcoming direct cosmic-ray measurements in the inner heliosphere by Parker Solar Probe and Solar Orbiter. They are also important for interpreting the gamma-ray emission from the Sun due to scattering of cosmic rays with solar matter and photons.

    ↳ astro-ph.SRastro-ph.EPastro-ph.HEhep-ph+2ApJ(2022)·15 citations
33. 33*

    Accelerating cosmology from a holographic wormhole

    Stefano Antonini🇺🇸 · Petar Simidzija🇨🇦 · Brian Swingle🇺🇸 · Mark Van Raamsdonk🇨🇦

    We consider cosmological models in which the cosmology is related via analytic continuation to a Euclidean asymptotically AdS planar wormhole geometry defined holographically via a pair of three-dimensional Euclidean CFTs. We argue that these models can generically give rise to an accelerating phase for the cosmology due to the potential energy of scalar fields associated with relevant scalar operators in the CFT. We explain how cosmological observables are related to observables in the wormhole spacetime and argue that this leads to a novel perspective on naturalness puzzles in cosmology.

    ↳ hep-thastro-ph.COhep-phPRL(2023)·45 citations
34. 34*

    Spectrum of Large N Glueballs: Holography vs Lattice

    Anatoly Dymarsky🇺🇸 · Dmitry Melnikov🇧🇷

    Recently there has been a notable progress in the study of glueball states in lattice gauge theories, in particular extrapolating their spectrum to the limit of large number of colors $N$. In this note we compare the large $N$ lattice results with the holographic predictions, focusing on the Klebanov-Strassler model. We note that glueball spectrum demonstrates approximate universality across a range of gauge theory models. Because of this universality the holographic models can give reliable predictions for the spectrum of pure $SU(N)$ Yang-Mills theories with and without supersymmetry. This is especially important for the supersymmetric theories, for which no firm lattice predictions exist yet, and the holographic models remain the most tractable approach. For non-supersymmetric pure $SU(N)$ theories with large $N$ we find an agreement within 5-8% between the lattice and holographic predictions for the mass ratios of the lightest states in various sectors. In particular both lattice and holography give predictions for the $2^{++}$ and $1^{--}$ mass ratio, consistent with the known constraints on the pomeron and odderon Regge trajectories.

    ↳ hep-lathep-phhep-thJHEP(2022)·4 citations
35. 35*

    Searching for Dark Clumps with Gravitational-Wave Detectors

    Sebastian Baum🇺🇸 · Michael A. Fedderke🇺🇸 · Peter W. Graham🇺🇸

    Dark compact objects ("clumps") transiting the Solar System exert accelerations on the test masses (TM) in a gravitational-wave (GW) detector. We reexamine the detectability of these clump transits in a variety of current and future GW detectors, operating over a broad range of frequencies. TM accelerations induced by clump transits through the inner Solar System have frequency content around $f\sim \mu$Hz. Some of us [arXiv:2112.11431] recently proposed a GW detection concept with $\mu$Hz sensitivity, based on asteroid-to-asteroid ranging. From the detailed sensitivity projection for this concept, we find both analytically and in simulation that purely gravitational clump-matter interactions would yield one detectable transit every $\sim 20$ yrs, if clumps with mass $m_{\text{cl}}\sim 10^{14}\text{kg}$ saturate the dark-matter (DM) density. Other (proposed) GW detectors using local TMs and operating in higher frequency bands are sensitive to smaller clump masses and have smaller rates of discoverable signals. We also consider the case of clumps endowed with an additional attractive long-range clump-matter fifth force significantly stronger than gravity (but evading known fifth-force constraints). For the $\mu$Hz detector concept, we use simulations to show that, for example, a clump-matter fifth-force $\sim 10^3$ times stronger than gravity with a range of $\sim \text{AU}$ would boost the rate of detectable transits to a few per year for clumps in the mass range $10^{11}\text{kg}\lesssim m_{\text{cl}}\lesssim 10^{14}\text{kg}$, even if they are a $\sim 1$% sub-component of the DM. The ability of $\mu$Hz GW detectors to probe asteroid-mass-scale dark objects that may otherwise be undetectable bolsters the science case for their development.

    ↳ astro-ph.COgr-qchep-phPRD(2022)·24 citations
36. 36*

    Gravidynamics, spinodynamics and electrodynamics within the framework of gravitational quantum field theory

    Yue-Liang Wu🇨🇳

    By noticing the fact that the charged leptons and quarks in the standard model are chirality-based Dirac spinors since their weak interaction violates maximally parity symmetry though they behave as Dirac fermions in electromagnetic interaction, we show that such a chirality-based Dirac spinor possesses not only electric charge gauge symmetry U(1) but also inhomogeneous spin gauge symmetry WS(1,3) = SP(1,3)$⋊$W${}^{1,3}$, which reveals the nature of gravity and spacetime. The gravitational force and spin gauge force are governed by the gauge symmetries $W^{1,3}$ and SP(1,3), respectively, and a biframe spacetime with globally flat Minkowski spacetime as base spacetime and locally flat gravigauge spacetime as a fiber is described by the gravigauge field through emergent non-commutative geometry. The gauge-geometry duality and renormalizability in gravitational quantum field theory (GQFT) are carefully discussed. A detailed analysis and systematic investigation on gravidynamics and spinodynamics as well as electrodynamics are carried out within the framework of GQFT. A full discussion on the generalized Dirac equation and Maxwell equation as well as Einstein equation and spin gauge equation is made in biframe spacetime. New effects of gravidynamics as extension of general relativity are particularly analyzed. All dynamic equations of basic fields are demonstrated to preserve the spin gauge covariance and general coordinate covariance due to the spin gauge symmetry and emergent general linear group symmetry GL(1,3,R), so they hold naturally in any spinning reference frame and motional reference frame.

    ↳ hep-thgr-qchep-phSCPMA(2023)·17 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.