Fri·Dec 16, 2022Friday·December 16, 2022

1. 01*

   Variant Nelson-Barr Mechanism with Minimal Flavor Violation

   Yang Bai🇺🇸 · George N. Wojcik🇺🇸

   Within the general framework of using spontaneous CP violation to solve the strong CP problem, we construct a variant Nelson-Barr model in which the Standard Model (SM) quark contribution to the strong CP phase is cancelled by new heavy QCD-charged fermions. This cancellation is ensured by choosing conjugate representations for the new colored states under the same global flavor symmetry of SM quarks. Choosing the global flavor symmetry to be that of minimal flavor violation, we suppress higher-order corrections to the strong CP phase to well below current experimental constraints. More than two dozen massless Goldstone bosons emerge from spontaneous flavor symmetry breaking, which yield strong astrophysical constraints on the symmetry breaking scale. In the early universe, the Goldstone bosons can be thermally produced from their interactions with the heavy colored fermions and contribute to $\Delta N_{\mathrm{eff}}$ at a measurable level. As a function of reheating temperature, the predicted $\Delta N_{\mathrm{eff}}$ shows an interesting plateau behavior we dub the ``flavor stairway", which encodes information about the SM quark flavor structure.

   hep-phJHEP(2023)·6 citations
2. 02*

   Cancellation of the sigma mode in the thermal pion gas by quark Pauli blocking

   David Blaschke🇵🇱 · Alexandra Friesen🇷🇺 · Yuriy Kalinovsky🇷🇺

   We calculate the pressure of the interacting pion gas using the Beth-Uhlenbeck approach to the relativistic virial expansion with Breit-Wigner phase shifts for the $\sigma$- and $\varrho$- meson resonances. The repulsive phase shift ${\delta }_0^2$ is taken from quark interchange model of Barnes and Swanson [Phys. Rev. D 46 (1992) 131] in very good agreement with experimental data. In this work we show that the cancellation of the attractive (I = 0) and repulsive (I = 2) isospin channel contributions to the scalar $\pi -\pi$ interaction in the low-energy region that is known for the vacuum phase shifts, takes place also at finite temperature. This happens despite the strong medium dependence of these phase shifts that enters our model by the temperature dependence of the $\sigma$- meson and constituent quark masses because for these masses the relation $m_{\sigma }(T)\approx 2m_q(T)$ holds and the scattering length approximation is valid as long as the strong decay channel $\sigma \to \pi \pi$ is open. Exploiting the Nambu--Jona-Lasinio model for describing the dynamical breaking of chiral symmetry in the vacuum and its restoration at finite temperature, we justify with our approach that the $\sigma$-meson should be absent from the hadron resonance gas description at low temperatures because the above cancellation holds. However, since this cancellation breaks down in the vicinity of the hadronization transition, where due to chiral symmetry restoration the decay channel $\sigma \to \pi \pi$ closes and the $\sigma$- meson becomes a good resonance, the latter should be included into the statistical model description of chemical freeze-out in heavy-ion collisions.

   hep-phnucl-thSymmetry(2023)·0 citations
3. 03*

   The $Z_7$ model of three-component scalar dark matter

   Geneviève Bélanger🇫🇷 · Alexander Pukhov🇷🇺 · Carlos E. Yaguna🇨🇴 · Óscar Zapata🇨🇴

   We investigate, for the first time, a scenario where the dark matter consists of three complex scalar fields that are stabilized by a single $Z_7$ symmetry. As an extension of the well-known scalar Higgs-portal, this $Z_7$ model is also subject to important restrictions arising from the relic density constraint and from direct detection experiments. Our goal in this paper is to find and characterize the viable regions of this model, and to analyze its detection prospects in future experiments. First, the processes that affect the relic densities are identified (they include semiannihilations and conversions) and then incorporated into the Boltzmann equations for the dark matter abundances, which are numerically solved with micrOMEGAs. By means of random scans of the parameter space, the regions consistent with current data, including the recent direct detection limit from the LZ experiment, are selected. Our results reveal that the $Z_7$ model is indeed viable over a wide range of dark matter masses and that both conversions and semiannihilations play an important role in determining the relic densities. Remarkably, we find that in many cases all three of the dark matter particles give rise to observable signals in future direct detection experiments, providing a suitable way to test this scenario.

   hep-phJHEP(2023)·31 citations
4. 04*

   Supercool subtleties of cosmological phase transitions

   Peter Athron🇨🇳 · Csaba Balázs🇦🇺 · Lachlan Morris🇦🇺

   We investigate rarely explored details of supercooled cosmological first-order phase transitions at the electroweak scale, which may lead to strong gravitational wave signals or explain the cosmic baryon asymmetry. The nucleation temperature is often used in phase transition analyses, and is defined through the nucleation condition: on average one bubble has nucleated per Hubble volume. We argue that the nucleation temperature is neither a fundamental nor essential quantity in phase transition analysis. We illustrate scenarios where a transition can complete without satisfying the nucleation condition, and conversely where the nucleation condition is satisfied but the transition does not complete. We also find that simple nucleation heuristics, which are defined to approximate the nucleation temperature, break down for strong supercooling. Thus, studies that rely on the nucleation temperature $—$ approximated or otherwise $—$ may misclassify the completion of a transition. Further, we find that the nucleation temperature decouples from the progress of the transition for strong supercooling. We advocate use of the percolation temperature as a reference temperature for gravitational wave production, because the percolation temperature is directly connected to transition progress and the collision of bubbles. Finally, we provide model-independent bounds on the bubble wall velocity that allow one to predict whether a transition completes based only on knowledge of the bounce action curve. We apply our methods to find empirical bounds on the bubble wall velocity for which the physical volume of the false vacuum decreases during the transition. We verify the accuracy of our predictions using benchmarks from a high temperature expansion of the Standard Model and from the real scalar singlet model.

   hep-phastro-ph.COJCAP(2023)·85 citations
5. 05*

   On the mass spectrum of heavy Higgs bosons in two-Higgs-doublet model in the light of the CDF $W$-mass anomaly

   Dong-Won Jung🇰🇷 · Yongtae Heo🇰🇷 · Jae Sik Lee🇰🇷

   We analyze the mass spectrum of the charged and neutral Higgs bosons in the framework of two Higgs doublet model (2HDM) in the light of the precision measurement of the $W$ boson mass by the CDF collaboration. We have considered the most general 2HDM potential with explicit CP violation in the Higgs basis which contains the three CP-mixed neutral mass eigenstates $H_1$, $H_2$, and $H_3$ with $M_{H_1}\le M_{H_2}\le M_{H_3}$. The high-precision CDF measurement of the $W$ boson mass is characterized by the large positive value of the $T$ parameter. By identifying the lightest neutral Higgs boson $H_1$ as the SM-like one discovered at the LHC, we find that it is necessary to have the mass splitting between the charged Higgs boson $H^{\pm }$ and the second heaviest neutral one $H_2$ to accommodate the sizable positive deviation of the $T$ parameter from its SM value of $0$. By combining the mass splitting between $H^{\pm }$ and $H_2$ with the theoretical constraints from the perturbative unitarity and for the Higgs potential to be bounded from below, we implement comprehensive analysis of the mass spectrum of the heavy Higgs bosons taking account of the effects of deviation from the alignment limit and also the mass splitting between $H_3$ and $H_2$. We further analyze the behavior of the heavy-Higgs mass spectrum according to the variation of the $T$ parameter. Finally, concentrating on the heavy mass region $M\equiv (M_{H_2}+M_{H^{\pm }})/2\text{gsim}500$ GeV in which we find a mass hierarchy of $M\gg M_{H_1}\sim |\Delta |\text{gsim}\delta$ with $\Delta \equiv M_{H_2}-M_{H^{\pm }}$ and $\delta \equiv M_{H_3}-M_{H_2}$, we discuss some benchmarking scenarios for the searches of heavy Higgs bosons at future colliders such as the high luminosity option of the LHC and a 100 TeV hadron collider.

   hep-phhep-exPRD(2023)·4 citations
6. 06*

   Dynamics of the pseudo-FIMP in presence of a thermal Dark Matter

   Subhaditya Bhattacharya🇮🇳 · Jayita Lahiri🇩🇪 · Dipankar Pradhan🇮🇳

   We demonstrate that in a two component dark matter (DM) set up, when DM${}_1$ is equilibrated with the thermal bath, the other DM${}_2$, in spite of having feeble or negligible interaction with the SM particles, can be brought to equilibrium just by having sizeable interaction with DM${}_1$. We propose that such DM candidates (DM${}_2$) should be classified into a category called pseudo-FIMP (pFIMP) having unique freeze-out characteristics which depend on the thermal DM partner. The draft elaborates upon the pFIMP properties from a generic coupled Boltzmann Equations (cBEQ) in a model independent way, followed by a concrete model illustration.

   hep-phhep-thPRD(2023)·8 citations
7. 07*

   On transverse single-spin asymmetries in $D$-meson production at the SPD NICA experiment

   Anton Karpishkov🇷🇺 · Vladimir Saleev🇷🇺

   In the present study we are interested in the Sivers effect in process $p^{\uparrow }p\to DX$. We calculate the transverse single-spin asymmetry (TSSA) of $D$-meson production within two phenomenological models, namely the Generalized Parton Model (GPM) and it's Colour Gauge-Invariant formulation (CGI-GPM), which takes into account the transverse momenta of initial partons. The last one allows us to study process-independent Sivers functions. To predict production cross-section of $D$-mesons we use a fragmentation approach with scale-independent Peterson fragmentation function, taking in mind nonzero masses of $c$-quark and $D$-mesons. Estimates for the TSSAs, as a function of transverse momentum and Feynman variable $x_F$ of $D$-meson, within the conditions of the planned SPD NICA experiment are presented for the first time.

   hep-phPhys.Part.Nucl.Lett.(2023)·3 citations
8. 08*

   Timelike Compton scattering in ultraperipheral $pPb$ collisions

   Ya-Ping Xie🇨🇳 · V. P. Goncalves🇧🇷

   The study of exclusive processes in photon - induced interactions allow us to probe the generalized parton distributions (GPDs), which provide information about the 3 dimensional description of the quark and gluon content of hadrons. In this paper we investigate the timelike Compton scattering (TCS) in ultraperipheral $pPb$ collisions at the LHC. Such process is characterized by the exclusive dilepton production through the subprocess $\gamma p\to {\gamma }^{\ast }p\to l^{+}{l}^{-}p$, with the real photon in the initial state being emitted by the nucleus. Assuming a given model for the GPDs, the TCS differential cross section is estimated as well the contribution associated to the interference between the TCS and Bethe - Heitler (BH) amplitudes. Predictions for the TCS, BH and interference contributions are presented considering the kinematical range covered by the LHC detectors.

   hep-phPLB(2023)·9 citations
9. 09*

   Pion and photon beam initiated backward charmonium or lepton pair production

   Bernard Pire🇫🇷 · Kirill M. Semenov-Tian-Shansky🇰🇷 · Alisa A. Shaikhutdinova🇷🇺 · Lech Szymanowski🇵🇱

   Hard exclusive reactions initiated by pion or photon beams within the near-backward kinematical regime specified by the small Mandelstam variable $-u$ can be studied to access pion-to-nucleon and photon-to-nucleon Transition Distribution Amplitudes (TDAs). Checking the validity of collinear factorized description of pion and photon induced reactions in terms of TDAs allows to test the universality of TDAs between the space-like and time-like regimes that is the indispensable feature of the QCD collinear factorization approach. In this short review we consider the exclusive pion- and photo-production off nucleon of a highly virtual lepton pair (or heavy quarkonium) in the near-backward region. We first employ a simplistic cross channel nucleon exchange model of pion-to-nucleon TDAs to estimate the magnitude of the corresponding cross sections for the kinematical conditions of J-PARC. We then illustrate the flexibility of our approach by building a two parameter model for the photon-to-nucleon TDAs based on preliminary results for near threshold $J/\psi$ photoproduction at JLab and provide our estimates for near-backward $J/\psi$ photoproduction and Timelike Compton Scattering cross sections for the kinematical conditions of JLab and of future EIC and EicC.

   hep-phhep-exnucl-exnucl-thAAPPS Bull.(2023)·11 citations
10. 10*

    The negligible impact of experimental inconsistencies in the NNPDF4.0 global dataset

    Roy Stegeman🇮🇹

    As both predictions and measurements of high-energy physics observables become more precise, controlling all sources of uncertainties in determinations of parton distribution functions (PDFs) becomes increasingly important. One source of PDF uncertainty is the result of data not being consistent under a chosen theoretical framework. In these proceedings we investigate the impact these inconsistencies present in the global NNPDF4.0 dataset. We show that, when accounting for missing higher order uncertainties, the missing contribution to the PDF uncertainty due to data inconsistencies are at the level of statistical fluctuations.

    hep-phhep-exPoS(2022)·2 citations
11. 11*

    Quark mass effects in double parton distributions

    Markus Diehl🇩🇪 · Riccardo Nagar🇮🇹 · Peter Plößl🇩🇪

    Double parton distributions can be computed from the perturbative splitting of one parton into two if the distance between the two observed partons is small. We develop schemes to take into account quark mass effects in this computation, and we study these schemes numerically at leading order in the strong coupling. Furthermore, we investigate in detail the structure of the next-to-leading order corrections to the splitting kernels that include quark mass effects.

    hep-phJHEP(2023)·8 citations
12. 12*

    Multi-step phase transition and gravitational wave from general ${\mathbb{Z}}_2$ scalar extensions

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

    Multi-step phase transition provides a paradigm in which a broken symmetry during phase transition can be restored, enriching the phenomena of both dark matter and baryon asymmetry. We study the dynamics of the multi-step phase transition in the standard model extension with additional isospin $N$-plet scalar field ${\Phi }_2$ under a discrete ${\mathbb{Z}}_2$ symmetry. We find that the multi-step phase transition could be triggered if there is a moderately large coupling between the Higgs and the ${\Phi }_2$ and this coupling is required to be larger as the mass of the ${\Phi }_2$ and/or isospin increase. The first-order phase transition at the first (second) step can be realized by the thermal loop (tree-level barrier) effects. Thus it is more likely that a detectable spectrum of gravitational waves can be produced at the second step of the phase transition.

    hep-phPRD(2025)·20 citations
13. 13*

    $C$ and $CP$ violation in effective field theories

    Hakan Akdag🇩🇪 · Bastian Kubis🇩🇪 · Andreas Wirzba🇩🇪

    The quest for new sources of the simultaneous violation of $C$ and $CP$ symmetry was popular in the 1960s and has since been mostly neglected for more than half a century. In this work we revisit fundamental quark-level operators that break $C$ and $CP$ up to and including mass dimension 8 for flavor-conserving transitions, relying on the complete operator sets of the so-called Standard Model effective field theory and the low-energy effective field theory. With the formalism of chiral perturbation theory, we match these quark operators to light-meson physics, derive $C$- and $CP$-odd Lagrangians for several processes in the $\eta$, ${\eta }^{\prime }$, and pion sectors, and furthermore, as a proof of principle, give estimates for the respective observables in explicit dependence of the underlying high-energy scale for new physics.

    hep-phnucl-thJHEP(2023)·17 citations
14. 14*

    Removing the Cosmological Bound on the Axion Scale in the KSVZ and DFSZ Models

    Emmanouil Koutsangelas🇩🇪

    It is known for some time that the cosmological bound on the invisible axion scale can be avoided by an early phase of strong QCD. While most approaches rely on theories where the strong coupling constant is determined through the expectation value of some scalar field, we show that this mechanism can also be implemented into the benchmark KSVZ and DFSZ models when the early phase of strong QCD emerges by the modification of the running coupling during inflation. For both models the physics that are responsible for making QCD strong do not displace the axions minimum by too much, so that the efficiency of the relaxation is controlled by parameters of the theory and the number of inflationary e-folds. In particular, we consider the case of very efficient relaxation where the axion abundance is dominated by inflationary quantum and post-inflationary thermal fluctuations. Within this situation we identify the parameter space compatible with all cosmological constrains and derive conditions on the reheating temperature and the QCD scale during inflation that result in the axion making up all the dark matter. Due to duality below the Peccei-Quinn scale and a minor influence of the KSVZ and DFSZ fields on the running, our findings also apply to a minimal 2-form implementation of the axion.

    hep-phastro-ph.COPRD(2023)·13 citations
15. 15*

    Dark Matter stimulated neutrinoless double beta decay

    Francesco Nozzoli🇮🇹 · Cinzia Cernetti🇮🇹

    Nuclei that are unstable with respect to double beta decay are investigated in this work for a novel Dark Matter (DM) direct detection approach. In particular, the diagram responsible for the neutrinoless double beta decay will be considered for the possible detection technique of a Majorana DM fermion inelastically scattering on a double beta unstable nucleus, stimulating its decay. The exothermic nature of the stimulated double beta decay would allow the direct detection also of a light DM fermion, a class of DM candidates that are difficult or impossible to investigate with the traditional elastic scattering techniques. The expected signal distribution for different DM masses and the upper limits on the nucleus scattering cross sections, are shown and compared with the existing data for the case of ${}^{136}$Xe nucleus.

    hep-phastro-ph.COastro-ph.IM5 citations
16. 16*

    Can the two-pole structure of the $D_0^{\ast }(2300)$ be understood from recent lattice data?

    Anuvind Asokan🇩🇪 · Meng-Na Tang🇨🇳 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Yuki Kamiya🇩🇪 · Ulf-G. Meißner🇩🇪

    It was demonstrated in a series of papers employing unitarized chiral perturbation theory that the phenomenology of the scalar open-charm state, the $D_0^{\ast }(2300)$, can be understood as the interplay of two poles, corresponding to two scalar-isospin doublet states with different SU(3) flavor content. Within this formalism the lightest open charm positive parity states emerge as being dynamically generated from the scattering of the Goldstone-boson octet off $D$ mesons, a picture that at the same time solves various problems that the experimental observations posed. However, in recent lattice studies of $D\pi$ scattering at different pion masses only one pole was reported in the $D_0^{\ast }$ channel, while it was not possible to extract reliable parameters of a second pole from the lattice data. In this paper we demonstrate how this seeming contradiction can be understood and that imposing SU(3) constraints on the fitting amplitudes allows one to extract information on the second pole from the lattice data with minimal bias. The results may also be regarded as a showcase how approximate symmetries can be imposed in the $K$-matrix formalism to reduce the number of parameters.

    hep-phhep-exhep-latnucl-thEPJC(2023)·26 citations
17. 17*

    Forward production of prompt neutrinos from charm in the atmosphere and at high energy colliders

    Weidong Bai🇨🇳 · Milind Diwan🇺🇸 · Maria Vittoria Garzelli🇩🇪 · Yu Seon Jeong🇰🇷 · Karan Kumar🇺🇸 · Mary Hall Reno🇺🇸

    The high-energy atmospheric neutrino flux is dominated by neutrinos from the decays of charmed hadrons produced in the forward direction by cosmic ray interactions with air nuclei. We evaluate the charm contributions to the prompt atmospheric neutrino flux as a function of the center-of-mass energy $\sqrt{s}$ of the hadronic collision and of the center-of-mass rapidity $y$ of the produced charm hadron. Uncertainties associated with parton distribution functions are also evaluated as a function of $y$. We find that the $y$ coverage of LHCb for forward heavy-flavour production, complemented by the angular coverage of present and future forward neutrino experiments at the LHC, bracket the most interesting $y$ regions for the prompt atmospheric neutrino flux. At $\sqrt{s}=14$ TeV foreseen for the HL-LHC phase, nucleon collisions in air contribute to the prompt neutrino flux prominently below $E_{\nu }\sim 10^7$~GeV. Measurements of forward charm and/or forward neutrinos produced in hadron collisions up to $\sqrt{s}=100$ TeV, which might become possible at the FCC, are relevant for the prompt atmospheric neutrino flux up to $E_{\nu }=10^8$ GeV and beyond.

    hep-phastro-ph.HEJHEP(2023)·31 citations
18. 18*

    Domain Wall Network: A Dual Solution for Gravitational Waves and Hubble Tension?

    Ligong Bian🇨🇳 · Shuailiang Ge🇨🇳 · Changhong Li🇨🇳 · Jing Shu🇨🇳 · Junchao Zong🇨🇳

    We explore the possibility that domain wall networks generate the stochastic gravitational wave background (SGWB) observed as a strong common power-law process in the Data Release-2 of Parkes Pulsar Timing Array. We find that a broad range of parameters, specifically wall tension around ${\sigma }_{\text{DW}}\sim (29-414,\text{TeV}{)}^3$ and wall-decay temperature within $T_d\sim 20-257,\text{MeV}$, can explain this phenomenon at a $68\%$ credible level. Meanwhile, the same parameters could ease the Hubble tension if particles from these domain wall networks decay into dark radiation. We establish a direct analytical relationship, ${\Omega }_{\text{GW}}(f_p,T_0)h^2\sim {\Omega }_{\text{rad}}{h}^2({\Omega }_{\nu }\Delta N_{\text{eff}}{)}^2$, to illustrate this coincidence, underlining its importance in the underlying physics and potential applicability to a wider range of models and data. Conversely, if the common power-law process is not attributed to domain wall networks, our findings impose tight limits on the wall tension and decay temperature.

    hep-phastro-ph.COgr-qchep-thSCPMA(2024)·28 citations
19. 19*

    Mass-varying Dark Matter from a Phase Transition

    Sayan Mandal🇺🇸 · Neelima Sehgal🇺🇸

    We propose a mass-varying dark matter (MVDM) model consisting of a scalar field and a fermionic field interacting via a simple Yukawa coupling, and containing an exponential self-interaction potential for the scalar field. Analyzing the evolution of this coupled scalar-fermion system in an expanding Universe, we find that it initially behaves like radiation but then undergoes a phase transition after which it behaves like pressureless dark matter. The one free parameter of this model is the temperature at which the phase transition occurs; the mass of the dark matter particle, given by the mass of the fermion, is derived from this. For a phase transition temperature between 10 MeV and $10^7$ GeV, the current dark matter relic density is achieved for a fermion mass in the range of 1 GeV to $10^9$ GeV. In this dark matter model, the scalar becomes a sub-dominant unclustered component of dark matter that can lower the amplitude of structure formation by up to a few percent. Another feature is that the mass-varying fermion component can lead to discrepant measurements of the current dark matter density of about ten percent inferred from early and late-time probes assuming LCDM.

    hep-phastro-ph.COhep-thPRD(2023)·6 citations
20. 20*

    Three-Body Unitary Coupled-Channel Analysis on $\eta (1405/1475)$

    S. X. Nakamura (Univ. of Science and Technology of China)🇨🇳 · Q. Huang (Nanjing Normal Univ.)🇨🇳 · J. -J. Wu (Univ. of Chinese Academy of Sciences)🇨🇳 · H. P. Peng (Univ. of Science and Technology of China)🇨🇳 · Y. Zhang (Univ. of Science and Technology of China)🇨🇳 · Y. C. Zhu (Univ. of Science and Technology of China)🇨🇳

    The recent BESIII data on $J/\psi \to \gamma (K_S{K}_S{\pi }^0)$, which is significantly more precise than earlier $\eta (1405/1475)$-related data, enables quantitative discussions on $\eta (1405/1475)$ at the previously unreachable level. We conduct a three-body unitary coupled-channel analysis of experimental Monte-Carlo outputs for radiative $J/\psi$ decays via $\eta (1405/1475)$: $K_S{K}_S{\pi }^0$ Dalitz plot distributions from the BESIII, and branching ratios of $\gamma (\eta {\pi }^{+}{\pi }^{-})$ and $\gamma (\gamma {\pi }^{+}{\pi }^{-})$ final states relative to that of $\gamma (K\bar{K}\pi )$. Our model systematically considers (multi-)loop diagrams and an associated triangle singularity, which is critical in making excellent predictions on $\eta (1405/1475)\to \pi \pi \pi$ lineshapes and branching ratios. The $\eta (1405/1475)$ pole locations are revealed for the first time. Two poles for $\eta (1405)$ are found on different Riemann sheets of the $K^{\ast }\bar{K}$ channel, while one pole for $\eta (1475)$. The $\eta (1405/1475)$ states are described with two bare states dressed by continuum states. The lower bare state would be an excited ${\eta }^{\prime }$, while the higher one could be an excited ${\eta }^{(\prime )}$, hybrid, glueball, or their mixture. This work presents the first-ever pole determination based on a manifestly three-body unitary coupled-channel framework applied to experimental three-body final state distributions (Dalitz plots).

    hep-phhep-exnucl-thPRD(2023)·13 citations
21. 21*

    Disentangling Sub-GeV Dark Matter from the Diffuse Supernova Neutrino Background using Hyper-Kamiokande

    Sandra Robles🇬🇧

    The upcoming Hyper-Kamiokande (HyperK) experiment is expected to detect the Diffuse Supernova Neutrino Background (DSNB). This requires to ponder all possible sources of background. Sub-GeV dark matter (DM) which annihilates into neutrinos is a potential background that has not been considered so far. We simulate DSNB and DM signals, as well as backgrounds in the HyperK detector. We find that DM-induced neutrinos could indeed alter the extraction of the correct values of the parameters of interest for DSNB physics. Since the DSNB is an isotropic signal, and DM originates primarily from the Galactic centre, we show that this effect could be alleviated with an on-off analysis.

    hep-phastro-ph.COastro-ph.HEhep-exSciPost Phys.Proc.(2023)·1 citation
22. 22*

    Probing Lepton Number Violation and Majorana Nature of Neutrinos at the LHC

    K. S. Babu🇺🇸 · Rahool Kumar Barman🇺🇸 · Dorival Gonçalves🇺🇸 · Ahmed Ismail🇺🇸

    Observation of lepton number ($L$) violation by two units at colliders would provide evidence for the Majorana nature of neutrinos. We study signals of $L$-violation in the context of two popular models of neutrino masses, the type-II seesaw model and the Zee model, wherein small neutrino masses arise at the tree-level and one-loop level, respectively. We focus on $L$-violation signals at the LHC arising through the process $pp\to {\ell }^{\pm }{\ell }^{\prime \pm }$ + jets within these frameworks. We obtain sensitivity to $L$-violation in the type-II seesaw model for triplet scalar masses up to 700 GeV and in the Zee model for charged scalar masses up to 4.8 TeV at the high-luminosity LHC with an integrated luminosity of $3{\text{ab}}^{-1}$.

    hep-phhep-exJHEP(2024)·14 citations
23. 23*

    Transient Radio Lines from Axion Miniclusters and Axion Stars

    Samuel J. Witte🇳🇱 · Sebastian Baum🇺🇸 · Matthew Lawson🇸🇪 · M.C. David Marsh🇸🇪 · Alexander J. Millar🇸🇪 · Gustavo Salinas🇸🇪

    Gravitationally bound clumps of dark matter axions in the form of 'miniclusters' or even denser 'axion stars' can generate strong radio signals through axion-photon conversion when encountering highly magnetised neutron star magnetospheres. We systematically study encounters of axion clumps with neutron stars and characterise the axion infall, conversion and the subsequent propagation of the photons. We show that the high density and low escape velocity of the axion clumps lead to strong, narrow, and temporally characteristic transient radio lines with an expected duration varying from seconds to months. Our work comprises the first end-to-end modeling pipeline capable of characterizing the radio signal generated during these transient encounters, quantifying the typical brightness, anisotropy, spectral width, and temporal evolution of the radio flux. The methods developed here may prove essential in developing dedicated radio searches for transient radio lines arising from miniclusters and axion stars.

    hep-phastro-ph.COPRD(2023)·39 citations
24. 24*

    Anticipating a New-Physics Signal in Upcoming 21-cm Power Spectrum Observations

    Rennan Barkana🇮🇱 · Anastasia Fialkov🇬🇧 · Hongwan Liu🇺🇸 · Nadav Joseph Outmezguine🇺🇸

    Dark matter-baryon interactions can cool the baryonic fluid, which has been shown to modify the cosmological 21-cm global signal. We show that in a two-component dark sector with an interacting millicharged component, dark matter-baryon scattering can produce a 21-cm power spectrum signal with acoustic oscillations. The signal can be up to three orders of magnitude larger than expected in $\Lambda$CDM cosmology, given realistic astrophysical models. This model provides a new-physics target for near-future experiments such as HERA or NenuFAR, which can potentially discover or strongly constrain the dark matter explanation of the putative EDGES anomaly.

    hep-phastro-ph.COPRD(2023)·25 citations
25. 25*

    The Supercooling Window at Weak and Strong Coupling

    Noam Levi🇮🇱 · Toby Opferkuch🇺🇸 · Diego Redigolo🇮🇹

    Supercooled first order phase transitions are typical of theories where conformal symmetry is predominantly spontaneously broken. In these theories the fate of the flat scalar direction is highly sensitive to the size and the scaling dimension of the explicit breaking deformations. For a given deformation, the coupling must lie in a particular region to realize a supercooled first order phase transition. We identify the supercooling window in weakly coupled theories and derive a fully analytical understanding of its boundaries. Mapping these boundaries allows us to identify the deformations enlarging the supercooling window and to characterize their dynamics analytically. For completeness we also discuss strongly coupled conformal field theories with an holographic dual, where the complete characterization of the supercooling window is challenged by calculability issues.

    hep-phJHEP(2023)·48 citations
26. 26*

    Are gluon showers inside a quark-gluon plasma strongly coupled? a theorist's test

    Peter Arnold🇺🇸 · Omar Elgedawy🇺🇸 · Shahin Iqbal🇵🇰

    We study whether in-medium showers of high-energy gluons can be treated as a sequence of individual splitting processes $g\to gg$, or whether there is significant quantum overlap between where one splitting ends and the next begins. Accounting for the Landau-Pomeranchuk-Migdal (LPM) effect, we calculate such overlap effects to leading order in high-energy ${\alpha }_{\mathrm{s}}(\mu )$ for the simplest theoretical situation. We investigate a measure of overlap effects that is independent of physics that can be absorbed into an effective value ${\hat{q}}_{\mathrm{eff}}$ of the jet-quenching parameter $\hat{q}$.

    hep-phnucl-thPRL(2023)·21 citations
27. 27*

    Asymptotic safety of gravity with matter

    Astrid Eichhorn🇩🇰 · Marc Schiffer🇨🇦

    The asymptotic-safety paradigm posits that the symmetry of quantum theories of gravity and matter is enhanced to quantum scale symmetry, i.e., scale symmetry in the presence of quantum fluctuations, at very high energies. To achieve such a symmetry enhancement, the effect of quantum fluctuations must balance out. It is to be expected that such a balance can only be achieved within a set of theories with limited field content and interaction structure. In this chapter, we review how much is known about these limits. From the quantum scale invariant regime, the theory transits to a theory with distinct physical scales - most importantly masses for various elementary particles - at low energies. There, quantum scale invariance can leave its imprint in relations between various interactions and mass scales of the theory. These relations can be compared to experimental data, which has two possible implications: first, if the relations do not match the data, the underlying quantum theory of gravity and matter, formulated at and beyond the Planck scale, has been ruled out using experimental data from energies much below the Planck scale. Second, if the relations match the data, the asymptotic-safety paradigm provides a first-principles derivation of free parameters of the Standard Model. Most importantly, this may include the ratios of the Higgs mass to the electroweak scale as well as the value of the finestructure constant. Similarly, theories beyond the Standard Model may come with fewer free parameters than in their effective-field-theory incarnation without gravity. This may lead to an explanation of the smallness of neutrinos masses and predictions for the nature and interactions of dark matter.

    ↳ hep-thgr-qchep-ph74 citations
28. 28*

    Dynamics and Equation of State Dependencies of Relevance for Nucleosynthesis in Supernovae and Neutron Star Mergers

    H.-Thomas Janka (1) · Andreas Bauswein (2) ((1) MPI for Astrophysics, Garching, (2) GSI, Darmstadt)

    Neutron stars (NSs) and black holes (BHs) are born when the final collapse of the stellar core terminates the lives of stars more massive than about 9 Msun. This can trigger the powerful ejection of a large fraction of the star's material in a core-collapse supernova (CCSN), whose extreme luminosity is energized by the decay of radioactive isotopes such as 56Ni and 56Co. When evolving in close binary systems, the compact relics of such infernal catastrophes spiral towards each other on orbits gradually decaying by gravitational-wave emission. Ultimately, the violent collision of the two components forms a more massive, rapidly spinning remnant, again accompanied by the ejection of considerable amounts of matter. These merger events can be observed by high-energy bursts of gamma rays with afterglows and electromagnetic transients called kilonovae, which radiate the energy released in radioactive decays of freshly assembled rapid neutron-capture elements. By means of their mass ejection and the nuclear and neutrino reactions taking place in the ejecta, both CCSNe and compact object mergers (COMs) are prominent sites of heavy-element nucleosynthesis and play a central role in the cosmic cycle of matter and the chemical enrichment history of galaxies. The nuclear equation of state (EoS) of NS matter, from neutron-rich to proton-dominated conditions and with temperatures ranging from about zero to ~100 MeV, is a crucial ingredient in these astrophysical phenomena. It determines their dynamical processes, their remnant properties even at the level of deciding between NS or BH, and the properties of the associated emission of neutrinos, whose interactions govern the thermodynamic conditions and the neutron-to-proton ratio for nucleosynthesis reactions in the innermost ejecta. This chapter discusses corresponding EoS dependent effects of relevance in CCSNe as well as COMs. (slightly abridged)

    ↳ astro-ph.HEgr-qchep-phnucl-th19 citations
29. 29*

    Adiabatically compressed wave dark matter halo and intermediate-mass ratio inspirals

    Hyungjin Kim🇩🇪 · Alessandro Lenoci🇩🇪 · Isak Stomberg🇩🇪 · Xiao Xue🇩🇪

    The adiabatic growth of a central massive black hole could compress the surrounding dark matter halo, leading to a steeper profile of the dark matter halo. This phenomenon is called adiabatic compression. We investigate the adiabatic compression of wave dark matter - a light bosonic dark matter candidate with its mass smaller than a few eV. Using the adiabatic theorem, we show that the adiabatic compression leads to a much denser wave dark matter halo similar to the particle dark matter halo in the semiclassical limit. The compressed wave halo differs from that of the particle halo near the center where the semiclassical approximation breaks down, and the central profile depends on dark matter and the central black hole mass as they determine whether the soliton and low angular momentum modes can survive over the astrophysical time scale without being absorbed by the black hole. Such a compressed profile has several astrophysical implications. As one example, we study the gravitational waves from the inspiral between a central intermediate-mass black hole and a compact solar-mass object within the wave dark matter halo. Due to the enhanced mass density, the compressed wave dark matter halo exerts stronger dynamical friction on the orbiting object, leading to the dephasing of the gravitational waves. The pattern of dephasing is distinctive from that of inspirals in the particle dark matter halo because of the difference in density profile and because of the relatively suppressed dynamical friction force, originating from the wave nature of dark matter. We investigate the prospects of future gravitational wave detectors, such as Laser Interferometer Space Antenna, and identify physics scenarios where the wave dark matter halo can be reconstructed from gravitational wave observations.

    ↳ astro-ph.GAgr-qchep-phPRD(2023)·31 citations
30. 30*

    Erasure of Strings and Vortexes

    Gia Dvali🇩🇪 · Juan Sebastián Valbuena-Bermúdez🇩🇪

    The interaction of defects can lead to a phenomenon of erasure. During this process, a lower-dimensional object gets absorbed and dissolved by a higher-dimensional one. The phenomenon is very general and has a wide range of implications, both cosmological and fundamental. In particular, all types of strings, such as cosmic strings, QCD flux tubes, or fundamental strings, get erased when encountering a defect, either solitonic or a $D$-brane that deconfines their fluxes. This leads to a novel mechanism of cosmic string break-up, accompanied by gravitational and electromagnetic radiations. The arguments based on loss of coherence and the entropy count suggest that the erasure probability is very close to one, and strings never make it through the deconfining layer. We confirm this by a numerical simulation of the system, which effectively captures the essence of the phenomenon: a $2+1$-dimensional problem of interaction between a Nielsen-Olesen vortex of a $U(1)$ Higgs model and a domain wall inside which the $U(1)$ gauge group is unHiggsed and the magnetic flux is deconfined. In accordance with the entropy argument, in our simulation, the vortex never makes it across the wall.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2023)·15 citations
31. 31*

    Charm mass effects in the static energy computed in 2+1+1 flavor lattice QCD

    Johannes Heinrich Weber🇩🇪 · Nora Brambilla🇩🇪 · Rafael L. Delgado🇪🇸 · Andreas Kronfeld🇺🇸 · Viljami Leino🇩🇪 · Peter Petreczky🇺🇸 · Sebastian Steinbeißer🇩🇪 · Antonio Vairo🇩🇪

    We report our analysis for the static energy in (2+1+1)-flavor QCD over a wide range of lattice spacings and several quark masses. We obtain results for the static energy out to distances of nearly 1 fm, allowing us to perform a simultaneous determination of the lattice scales $r_2$, $r_1$ and $r_0$ as well as the string tension, $\sigma$. While our results for $r_0/r_1$ and $r_0$ $\sqrt{\sigma }$ agree with published (2+1)-flavor results, our result for $r_1/r_2$ differs significantly from the value obtained in the (2+1)-flavor case, likely due to the effect of the charm quark. We study in detail the effect of the charm quark on the static energy by comparing our results on the finest lattices with the previously published (2+1)-flavor QCD results at similar lattice spacing. The lattice results agree well with the two-loop perturbative expression of the static energy incorporating finite charm mass effects.

    ↳ hep-lathep-phPoS(2023)·0 citations
32. 32*

    Prospects for measuring dark energy with 21 cm intensity mapping experiments: A joint survey strategy

    Peng-Ju Wu🇨🇳 · Yichao Li🇺🇸 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    The 21 cm intensity mapping (IM) technique provides us with an efficient way to observe the cosmic large-scale structure (LSS). From the LSS data, one can use the baryon acoustic oscillation and redshift space distortion to trace the expansion and growth history of the universe, and thus measure the dark energy parameters. In this paper, we make a forecast for cosmological parameter estimation with the synergy of three 21 cm IM experiments. Specifically, we adopt a novel joint survey strategy, FAST ($0<z<0.35$)+SKA1-MID ($0.35<z<0.8$)+HIRAX ($0.8<z<2.5$), to measure dark energy. We simulate the 21 cm IM observations under the assumption of excellent foreground removal. We find that the synergy of three experiments could place quite tight constraints on cosmological parameters. For example, it provides $\sigma ({\Omega }_{\mathrm{m}})=0.0039$ and $\sigma (H_0)=0.27\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ in the $\Lambda$CDM model. Notably, the synergy could break the cosmological parameter degeneracies when constraining the dynamical dark energy models. Concretely, the joint observation offers $\sigma (w)=0.019$ in the $w$CDM model, and $\sigma (w_0)=0.085$ and $\sigma (w_a)=0.32$ in the $w_0{w}_a$CDM model. These results are better than or equal to those given by CMB+BAO+SN. In addition, when the foreground removal efficiency is relatively low, the strategy still performs well. Therefore, the 21 cm IM joint survey strategy is promising and worth pursuing.

    ↳ astro-ph.COgr-qchep-phSCPMA(2023)·30 citations
33. 33*

    Tetraquarks and pentaquarks in lattice QCD with light and heavy quarks

    Pedro Bicudo🇵🇹

    We review how lattice QCD can contribute to the prediction and the comprehension of tetraquarks, pentaquarks and related exotic hadrons, with at least one heavy quark. We include all families of exotic hadrons, except for the quarkless glueballs and the hexaquarks which are related to nuclear physics. Since the discovery of quarks and the development of the QCD theory, there has been a large interest in exotic hadrons, initiated by the tetraquark models developed by Jaffe in 1977. Lattice QCD, being a first principle approach to solve non-perturbative QCD, has been crucial not only to compute precise results, but also to inspire research in hadronic physics. In the new millennium, this interest exploded with several experimental discoveries of tetraquark and pentaquark resonances with heavy quarks, starting with the Zc and Zb. Lattice QCD has not yet been able to comprehend this Z class of tetraquarks, and is developing new methods to determine their masses, decay widths and decay processes. The interest in tetraquarks was also fuelled by the lattice QCD prediction of a second class of tetraquarks such as the Tbb, boundstates in the sense of having no strong decays. Recently, the Tcc tetraquark, first predicted with quark models in 1982 by Richard et al, was observed experimentally. We expect the lattice QCD community will be able to explore this T class of tetraquarks in more detail and with very precise results. We report on all the different direct and indirect approaches that lattice QCD, with more focus on tetraquarks, has been employing to study exotic hadrons with at least one heavy quark. We also briefly review the experimental progress in observing tetraquarks and pentaquarks, and some of the theoretical paradigms of tetraquarks, including three different types of mechanisms (diquark, molecular and s pole), comparing them with the results of lattice QCD.

    ↳ hep-lathep-exhep-phPhys.Rept.(2023)·63 citations
34. 34*

    Hilbert series and higher-order Lagrangians for the $O(N)$ model

    Johan Bijnens🇸🇪 · Sven Bjarke Gudnason🇨🇳 · Jiahui Yu🇨🇳 · Tiantian Zhang🇨🇳

    We compare the Hilbert series approach with explicit constructions of higher-order Lagrangians for the $O(N)$ nonlinear sigma model. We use the Hilbert series to find the number and type of operators up to mass dimension 16, for spacetime dimension $D$ up to 12 and $N$ up to 12, and further classify the operators into spacetime parity and parity of the internal symmetry group $O(N)$. The explicit construction of operators is done up to mass dimension 12 for both parities even and dimension 10 for the other three cases. The results of the two methods are in full agreement. This provides evidence for the Hilbert series conjecture regarding co-closed but not co-exact $k$-forms, which takes into account the integration-by-parts relations.

    ↳ hep-thhep-phJHEP(2023)·12 citations
35. 35*

    The scaling of primordial gauge fields

    Massimo Giovannini🇨🇭

    The large-scale magnetic fields arising from the quantum mechanical fluctuations of the hypercharge are investigated when the evolution of the gauge coupling is combined with a sufficiently long inflationary stage. In this framework the travelling waves associated with the quantum mechanical initial conditions turn asymptotically into standing waves which are the gauge analog of the Sakharov oscillations. Even if the rate of dilution of the hypermagnetic and hyperelectric fields seems to be superficially smaller than expected from the covariant conservation of the energy-momentum tensor, the standard evolution for wavelengths larger than the Hubble radius fully accounts for this anomalous scaling which is anyway unable to increase the amplitude of the magnetic power spectra after symmetry breaking. An effective amplification of the gauge power spectra may instead occur when the post-inflationary expansion rate is slower than radiation. We stress that the modulations of the gauge power spectra freeze as soon as the relevant wavelengths reenter the Hubble radius and not at the end of inflation. After the Mpc scale crosses the comoving Hubble radius the scaling of the magnetic power spectrum follows from the dominance of the conductivity. From these two observations the late-time values of the magnetic power spectra are accurately computed in the case of a nearly scale-invariant slope and contrasted with the situation where the phases of Sakharov oscillations are not evaluated at horizon crossing but at the end of inflation, i.e. when all the wavelengths relevant for magnetogenesis are still larger than the comoving horizon.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2023)·3 citations
36. 36*

    Phase transitions and light scalars in bottom-up holography

    Daniel Elander🇫🇷 · Ali Fatemiabhari🇬🇧 · Maurizio Piai🇬🇧

    Within the bottom-up approach to holography, we construct a class of six-dimensional gravity models, and discuss solutions that can be interpreted, asymptotically in the far UV, in terms of dual five-dimensional conformal field theories deformed by a single scalar operator. We treat the scaling dimension of such operator, related to the mass of the one scalar field in the gravity theory, as a free parameter. One dimension in the regular geometry is compactified on a shrinking circle, hence mimicking confinement in the resulting dual four-dimensional theories. We study the mass spectrum of bosonic states. The lightest state in this spectrum is a scalar particle. Along the regular (confining) branch of solutions, we find the presence of a tachyonic instability in part of the parameter space, reached by a smooth deformation of the mass spectrum, as a function of the boundary value of the background scalar field in the gravity theory. In a region of parameter space nearby the tachyonic one, the lightest scalar particle can be interpreted as an approximate dilaton, sourced by the trace of the stress-energy tensor, and its mass is parametrically suppressed. We also compute the free energy, along several branches of gravity solutions. We find that both the dilatonic and tachyonic regions of parameter space, identified along the branch of confining solutions, are hidden behind a first-order phase transition, so that they are not realised as stable solutions, irrespectively of the scaling dimension of the deforming field-theory operator. The (approximate) dilaton, in particular, appears in metastable solutions. Yet, the mass of the lightest state, computed close to the phase transition, is (mildly) suppressed. This feature is amplified when the (free) parameter controlling the scaling dimension of the deformation is 5/2, half the dimension of space-time in the field theory.

    ↳ hep-thhep-lathep-phPRD(2023)·15 citations
37. 37*

    Finite energy sum rules for gravitational Regge amplitudes

    Toshifumi Noumi🇯🇵 · Junsei Tokuda🇯🇵

    We develop a framework to derive consistency constraints on gravitational Regge amplitudes based on the finite energy sum rules (FESRs), which directly connect gravitational Regge amplitudes at a finite ultraviolet scale with infrared physics without suffering from super-Planckian physics. For illustration, we consider four-point scattering of an identical massless scalar coupled to gravity. First, we derive multiple FESRs without relying on the $s\text{-}t\text{-}u$ permutation invariance. We then make use of FESRs, crossing symmetry, and other principles such as unitarity, to derive bounds on the Regge parameters. The bounds result in infrared finite gravitational positivity bounds in four spacetime dimensions.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2023)·30 citations
38. 38*

    The Cherenkov Telescope Array Will Test Whether Pulsars Generate the Galactic Center Gamma-Ray Excess

    Celeste Keith🇺🇸 · Dan Hooper🇺🇸 · Tim Linden🇸🇪

    The GeV-scale gamma-ray excess observed from the region surrounding the Galactic Center has been interpreted as either the products of annihilating dark matter particles, or as the emission from a large population of faint and centrally-located millisecond pulsars. If pulsars are responsible for this signal, they should also produce detectable levels of TeV-scale emission. In this study, we employ a template-based analysis of simulated data in an effort to assess the ability of the Cherenkov Telescope Array (CTA) to detect or constrain the presence of this emission, providing a new and powerful means of testing whether millisecond pulsars are responsible for the observed excess. We find that after even a relatively brief observation of the Inner Galaxy, CTA will be able to definitively detect this TeV-scale emission, or rule out pulsars as the source of the Galactic Center Gamma-Ray Excess.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2023)·9 citations
39. 39*

    Calculations in Lorentz-breaking scalar QED

    Jean C. C. Felipe🇧🇷 · A. Yu Petrov🇧🇷 · A. P. B. Scarpelli🇧🇷 · L. C. T. Brito🇧🇷

    We purpose a study a Lorentz-breaking extension of the scalar QED. We calculate the contributions in the Lorentz-violating parameters to the two-point functions of scalar and gauge fields. We found that the two background tensors, coming from the two sectors (scalar and gauge) are mixed in the one-loop corrections. This shows that these two Lorentz-breaking terms cannot be studied in an isolated form.

    ↳ hep-thhep-phProceedings of the Ninth Meeting on CPT a…·0 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.