Thu·Jun 29, 2023Thursday·June 29, 2023

1. 01*

   Dark photon production via elastic proton bremsstrahlung with non-zero momentum transfer

   Dmitry Gorbunov🇷🇺 · Ekaterina Kriukova🇷🇺

   We explore hypothetical vector particles, dark photons ${\gamma }^{\prime }$, which mix with the Standard Model photons and thus mediate interactions with charged particles into the hidden sector. We study the elastic proton bremsstrahlung of dark photons with masses 0.4-1.8 GeV, relevant for direct searches with proton accelerators. A key feature of our calculation is that it explicitly considers the non-zero momentum transfer between protons in the process $pp\to pp{\gamma }^{\prime }$. We compare the obtained differential and full bremsstrahlung cross sections with the results of other authors. Our calculation agrees well (up to 3-9 % corrections) with the Weizsacker-Williams approximation that confirms its applicability for proton beams. Then we refine predictions for the dark photon production with proton beams of energy 30 GeV, 70 GeV, 120 GeV and 400 GeV relevant for past, present and future experiments considered in literature.

   hep-phJHEP(2024)·18 citations
2. 02*

   Anomaly induced cooling of Neutron Stars: A Standard Model contribution

   Sabyasachi Chakraborty🇮🇳 · Aritra Gupta🇪🇸 · Miguel Vanvlasselaer🇧🇪

   Young neutron stars cool via the emission of neutrinos from their core. A precise understanding of all the different processes producing neutrinos in the hot and degenerate matter is essential for assessing the cooling rate of such stars. The main Standard Model processes contributing to this effect are $\nu$ bremsstrahlung, mURCA among others. In this paper, we investigate another Standard Model process initiated by the Wess-Zumino-Witten term, leading to the emission of neutrino pairs via $N\gamma \to N\nu \bar{\nu }$. We find that for proto-neutron stars, such processes, with degenerate neutrons, can be comparable and even dominate over the prototypical and well-known cooling mechanisms.

   hep-phJCAP(2023)·6 citations
3. 03*

   Theoretical study of scalar meson $a_0(1710)$ in the ${\eta }_c\to {\bar{K}}^0{K}^{+}{\pi }^{-}$ reaction

   Yan Ding🇨🇳 · Xiao-Hui Zhang🇨🇳 · Meng-Yuan Dai🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳 · Li-Sheng Geng🇨🇳 · Ju-Jun Xie🇨🇳

   We investigate the process ${\eta }_c\to {\bar{K}}^0{K}^{+}{\pi }^{-}$ by taking into account the $S$-wave $K^{\ast }{\bar{K}}^{\ast }$ and $\rho \omega$ interactions within the unitary coupled-channel approach, where the scalar meson $a_0(1710)$ is dynamically generated. In addition, the contributions from the intermediate resonances $K_0^{\ast }(1430{)}^{-}\to {\bar{K}}^0{\pi }^{-}$ and $K_0^{\ast }(1430{)}^0\to K^{+}{\pi }^{-}$ are also considered. We find a significant dip structure around 1.8~GeV, associated to the $a_0(1710)$, in the ${\bar{K}}^0{K}^{+}$ invariant mass distribution, and the clear peaks of the $K_0^{\ast }(1430)$ in the ${\bar{K}}^0{\pi }^{-}$ and $K^{+}{\pi }^{-}$ invariant mass distributions, consistent with the {\it BABAR} measurements. We further estimate the branching fractions $\mathcal{B}({\eta }_c\to {\bar{K}}^{\ast 0}{K}^{\ast +}{\pi }^{-})=5.5\times 10^{-3}$ and $\mathcal{B}({\eta }_c\to \omega {\rho }^{+}{\pi }^{-})=7.9\times 10^{-3}$. Our predictions can be tested by the BESIII and BelleII experiments in the future.

   hep-phPRD(2023)·14 citations
4. 04*

   The roles of the $T_{c\bar{s}0}(2900{)}^0$ and $D_0^{\ast }(2300)$ in the process $B^{-}\to D_s^{+}{K}^{-}{\pi }^{-}$

   Wen-Tao Lyu🇨🇳 · Yun-He Lyu🇨🇳 · Man-Yu Duan🇨🇳 · De-Min Li🇨🇳 · Dian-Yong Chen🇨🇳 · En Wang🇨🇳

   Motivated by the recent LHCb observations of $T_{c\bar{s}0}(2900{)}^0$ and $T_{c\bar{s}0}(2900{)}^{++}$ in the processes $B^0\to {\bar{D}}^0{D}_s^{+}{\pi }^{-}$ and $B^{+}\to D^{-}{D}_s^{+}{\pi }^{+}$, we have investigated the decay $B^{-}\to D_s^{+}{K}^{-}{\pi }^{-}$ by taking into account the contributions from the $S$-wave vector-vector interactions, and the $S$-wave $D_s^{+}{K}^{-}$ interactions. Our results show that the $D_s^{+}{K}^{-}$ invariant mass distribution has an enhancement structure near the threshold, associated with the $D_0^{\ast }(2300)$, which is in good agreement with the Belle measurements. We have also predicted the $D_s^{+}{\pi }^{-}$ invariant mass distribution and the Dalitz plot, which show the significant signal of the $T_{c\bar{s}0}(2900)$. With the same formalism, the $D_s^{-}{K}_s^0$ invariant mass distribution of the process $B^0\to D_s^{-}{K}_s^0{\pi }^{+}$ measured by Belle could be well reproduced, and the peak of $T_{c\bar{s}0}(2900)$ is expected to be observed around 2900~MeV in the $D_s^{-}{\pi }^{+}$ invariant mass distribution. Our results could be tested by the Belle II and LHCb experiments in the future.

   hep-phPRD(2024)·25 citations
5. 05*

   Heavy neutral 2HDM Higgs Boson Pair Production at CLIC Energies

   Majid Hashemi🇮🇷 · Marieh Molanaei🇮🇷

   In this work, the neutral Higgs boson pair production is analyzed at Compact Linear Collider (CLIC) to be operating at center of mass energies $\sqrt{s}$=1400 GeV (stage 2) and $\sqrt{s}$=3000 GeV (stage 3). The Higgs bosons to be searched for are neutral CP-even (H) and CP-odd (A) within the framework of two Higgs doublet model (2HDM) in the mass range 300 < mH/A < 1000 GeV. All types of the CP-conserving model are studied and the signal observability is evaluated taking into account the main SM background processes like ZZ, tt and the SM-like Higgs boson associated production (hZ). Results are presented for a set of model parameters and Higgs boson masses in terms of signal distributions over the background as well as the integrated luminosity needed for 5{\sigma} discovery. It is shown that the heavy mass region is well observable at CLIC in types 3 (flipped) and 4 (lepton-specific) in the regions not excluded by LHC so far, while in type 1 the signal observation is challenging due to the large jet multiplicity in the tt final state.

   hep-phPRD(2023)·4 citations
6. 06*

   A Pythagoras-like theorem for CP violation in neutrino oscillations

   Shu Luo🇨🇳 · Zhi-zhong Xing🇨🇳

   The probabilities of ${\nu }_{\mu }^{}\to {\nu }_e^{}$ and ${\overline{\nu }}_{\mu }^{}\to {\overline{\nu }}_e^{}$ oscillations in vacuum are determined by the CP-conserving flavor mixing factors ${\mathcal{R}}_{ij}^{}\equiv \mathrm{Re}(U_{\mu i}^{}{U}_{ej}^{}{U}_{\mu j}^{\ast }{U}_{ei}^{\ast })$ and the universal Jarlskog invariant of CP violation ${\mathcal{J}}_{\nu }^{}\equiv (-1{)}^{i+j}\mathrm{Im}(U_{\mu i}^{}{U}_{ej}^{}{U}_{\mu j}^{\ast }{U}_{ei}^{\ast })$ (for $i,j=1,2,3$ and $i<j$), where $U$ is the $3\times 3$ Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing matrix. We show that ${\mathcal{J}}_{\nu }^2={\mathcal{R}}_{12}^{}{\mathcal{R}}_{13}^{}+{\mathcal{R}}_{12}^{}{\mathcal{R}}_{23}^{}+{\mathcal{R}}_{13}^{}{\mathcal{R}}_{23}^{}$ holds as a natural consequence of the unitarity of $U$. This Pythagoras-like relation may provide a novel cross-check of the result of ${\mathcal{J}}_{\nu }^{}$ that will be directly measured in the next-generation long-baseline neutrino oscillation experiments. Indirect non-unitarity effects and terrestrial matter effects on ${\mathcal{J}}_{\nu }^{}$ and ${\mathcal{R}}_{ij}^{}$ are also discussed.

   hep-phhep-exPLB(2023)·5 citations
7. 07*

   Schwinger poles of the three-gluon vertex: symmetry and dynamics

   A. C. Aguilar🇧🇷 · M. N. Ferreira🇪🇸 · B. M. Oliveira🇧🇷 · J. Papavassiliou🇪🇸 · L. R. Santos🇧🇷

   The implementation of the Schwinger mechanism endows gluons with a nonperturbative mass through the formation of special massless poles in the fundamental QCD vertices; due to their longitudinal character, these poles do not cause divergences in on-shell amplitudes, but induce detectable effects in the Green's functions of the theory. Particularly important in this theoretical setup is the three-gluon vertex, whose pole content extends beyond the minimal structure required for the generation of a gluon mass. In the present work we analyze these additional pole patterns by means of two distinct, but ultimately equivalent, methods: the Slavnov-Taylor identity satisfied by the three-gluon vertex, and the nonlinear Schwinger-Dyson equation that governs the dynamical evolution of this vertex. Our analysis reveals that the Slavnov-Taylor identity imposes strict model-independent constraints on the associated residues, preventing them from vanishing. Approximate versions of these constraints are subsequently recovered from the Schwinger-Dyson equation, once the elements responsible for the activation of the Schwinger mechanism have been duly incorporated. The excellent coincidence between the two approaches exposes a profound connection between symmetry and dynamics, and serves as a nontrivial self-consistency test of this particular mass generating scenario.

   hep-phhep-lathep-thnucl-thEPJC(2023)·8 citations
8. 08*

   Inhomogeneous condensation in the Gross-Neveu model in noninteger spatial dimensions $1\le d<3$

   Laurin Pannullo🇩🇪

   The Gross-Neveu model in the $N\to \infty$ approximation in $d=1$ spatial dimensions exhibits a chiral inhomogeneous phase (IP), where the chiral condensate has a spatial dependence that spontaneously breaks translational invariance and the ${\mathbb{Z}}_2$ chiral symmetry. This phase is absent in $d=2$, while in $d=3$ its existence and extent strongly depends on the regularization and the value of the finite regulator. This work connects these three results smoothly by extending the analysis to non-integer spatial dimensions $1\le d<3$, where the model is fully renormalizable. To this end, we adapt the stability analysis, which probes the stability of the homogeneous ground state under inhomogeneous perturbations, to non-integer spatial dimensions. We find that the IP is present for all $d<2$ and vanishes exactly at $d=2$. Moreover, we find no instability towards an IP for $2\le d<3$, which suggests that the IP in $d=3$ is solely generated by the presence of a regulator.

   hep-phcond-mat.str-elnucl-thPRD(2023)·18 citations
9. 09*

   Corrections to the Forward Limit Dispersion Relations for $\gamma Z$-Exchange Contributions

   Qian-Qian Guo🇨🇳 · Hai-Qing Zhou🇨🇳

   The weak charge of the proton $Q_{\text{w}}$ is one of the most fundamental quantities in physics. It can be determined by measuring the parity asymmetry $A_{\text{PV}}$ in elastic $ep$ scattering, where the $\gamma Z$-exchange contributions are crucial. For the past fifteen years, dispersion relations (DRs) in the forward limit have been widely used as a model-independent method to estimate these contributions. In this work, we study corrections to these forward-limit DRs. We first estimate these corrections using pointlike interactions as an illustrative example. We then estimate the $\gamma Z$-exchange contributions for the upcoming P2 experiment through both direct calculation and the forward-limit DRs, within the framework of low-energy effective interactions. The results indicate that the correction to the forward-limit DR for ${\square }_{\gamma Z}^V$ is around 47\% for the upcoming P2 experiment, which will significantly modify the extracted value of $Q_{\text{w}}$.

   hep-phnucl-exnucl-thPRC(2024)·3 citations
10. 10*

    Precise predictions for the associated production of a $W$ boson with a top-antitop quark pair at the LHC

    Luca Buonocore🇨🇭 · Simone Devoto🇮🇹 · Massimiliano Grazzini🇨🇭 · Stefan Kallweit🇮🇹 · Javier Mazzitelli🇨🇭 · Luca Rottoli🇨🇭 · Chiara Savoini🇨🇭

    The production of a top-antitop quark pair in association with a $W$ boson ($t\bar{t}W$) is one of the heaviest signatures currently probed at the Large Hadron Collider (LHC). Since the first observation reported in 2015 the corresponding rates have been found to be consistently higher than the Standard Model predictions, which are based on next-to-leading order~(NLO) calculations in the QCD and electroweak (EW) interactions. We present the first next-to-next-to-leading order (NNLO) QCD computation of $t\bar{t}W$ production at hadron colliders. The calculation is exact, except for the finite part of the two-loop virtual corrections, which is estimated using two different approaches that lead to consistent results within their uncertainties. We combine the newly computed NNLO QCD corrections with the complete NLO QCD+EW results, thus obtaining the most advanced perturbative prediction available to date for the \ttW inclusive cross section. The tension with the latest ATLAS and CMS results remains at the $1\sigma -2\sigma$ level.

    hep-phhep-exPRL(2023)·97 citations
11. 11*

    PTArcade

    Andrea Mitridate🇩🇪 · David Wright🇺🇸 · Richard von Eckardstein🇩🇪 · Tobias Schröder🇩🇪 · Jonathan Nay🇺🇸 · Ken Olum🇺🇸 · Kai Schmitz🇩🇪 · Tanner Trickle🇺🇸

    This is a lightweight manual for PTArcade, a wrapper of ENTERPRISE and ceffyl that allows for easy implementation of new-physics searches in PTA data. In this manual, we describe how to get PTArcade installed (either on your local machine or an HPC cluster). We discuss how to define a stochastic or deterministic signal and how PTArcade implements these signals in PTA-analysis pipelines. Finally, we show how to handle and analyze the PTArcade output using a series of utility functions that come together with PTArcade.

    hep-phhep-ex109 citations
12. 12*

    Effects of the quark flavour thresholds in the hadronic vacuum polarization contributions to the muon anomalous magnetic moment

    A.V.Nesterenko🇷🇺

    The equivalent representations for the hadronic vacuum polarization contributions to the muon anomalous magnetic moment $a_{\mu }^{\text{HVP}}$ in the presence of the quark flavour thresholds are studied. Specifically, the explicit relations between the contributions given by the integration over a finite kinematic interval to $a_{\mu }^{\text{HVP}}$ expressed in terms of the hadronic vacuum polarization function, Adler function, and the $R$-ratio of electron-positron annihilation into hadrons are derived. It is shown that the quark flavour thresholds of the hadronic vacuum polarization function generate additional contributions to $a_{\mu }^{\text{HVP}}$ expressed in terms of the Adler function and the $R$-ratio and the explicit expressions for such contributions are obtained. The commonly employed dispersion relations, which bind together hadronic vacuum polarization function, Adler function, and $R$-ratio, are extended to account for the effects due to the quark flavour thresholds. The examined additional contributions due to the heavy quark thresholds to $a_{\mu }^{\text{HVP}}$ expressed in terms of the $R$-ratio appear to be quite sizable, that can be of a particular relevance for the data-driven method of assessment of the hadronic part of the muon anomalous magnetic moment.

    hep-phJ.Phys.G(2024)·3 citations
13. 13*

    Superfloccinaucinihilipilification: Semisimple unifications of any gauge theory

    Andrew Gomes🇺🇸 · Maximillian Ruhdorfer🇺🇸 · Joseph Tooby-Smith🇺🇸

    We present a Mathematica package that takes any reductive gauge algebra and fully-reducible fermion representation, and outputs all semisimple gauge extensions under the condition that they have no additional fermions, and are free of local anomalies. These include all simple completions, also known as grand unified theories (GUT). We additionally provide a list of all semisimple completions for 5835 fermionic extensions of the one-generation Standard Model.

    hep-phhep-thPRD(2023)·2 citations
14. 14*

    Renormalization scheme factorization of one-loop Fierz identities

    Jason Aebischer🇨🇭 · Marko Pesut🇨🇭 · Zachary Polonsky🇨🇭

    We present a proof of the factorization of renormalization scheme in one-loop-corrected Fierz identities. This scheme factorization facilitates the simultaneous transformation of operator basis and renormalization scheme using only relations between physical operators; the evanescent operators in the respective bases may be chosen entirely independently of each other. The relations between evanescent operators in the two bases is automatically accounted for by the corrected Fierz identities. We illustrate the utility of this result with a two-loop anomalous dimension matrix computation using the Naive-Dimensional Regularization scheme, which is then transformed via one-loop Fierz identities to the known result in the literature given in a different basis and calculated in the Larin scheme. Additionally, we reproduce results from the literature of basis transformations involving the rotation of evanescent operators into the physical basis using our method, without the need to explicitly compute one-loop matrix elements of evanescent operators.

    hep-phJHEP(2024)·21 citations
15. 15*

    The $q_T$ spectrum for Higgs production via heavy quark annihilation at N${}^3$LL${}^{\prime }$+aN${}^3$LO

    Pedro Cal🇩🇪 · Rebecca von Kuk🇩🇪 · Matthew A. Lim🇬🇧 · Frank J. Tackmann🇩🇪

    We study the transverse momentum ($q_T$) spectrum of the Higgs boson produced via the annihilation of heavy quarks ($s,c,b$) in proton-proton collisions. Using soft-collinear effective theory (SCET) and working in the five-flavour scheme, we provide predictions at three-loop order in resummed perturbation theory (N${}^3$LL${}^{\prime }$). We match the resummed calculation to full fixed-order results at next-to-next-to-leading order (NNLO), and introduce a decorrelation method to enable a consistent matching to an approximate N${}^3$LO (aN${}^3$LO) result. Since the $b$-quark initiated process exhibits large nonsingular corrections, it requires special care in the matching procedure and estimation of associated theoretical uncertainties, which we discuss in detail. Our results constitute the most accurate predictions to date for these processes in the small $q_T$ region and could be used to improve the determination of Higgs Yukawa couplings from the shape of the measured Higgs $q_T$ spectrum.

    hep-phPRD(2024)·16 citations
16. 16*

    Detection of Bosenovae with Quantum Sensors on Earth and in Space

    Jason Arakawa🇺🇸 · Joshua Eby🇯🇵 · Marianna S. Safronova🇺🇸 · Volodymyr Takhistov🇯🇵 · Muhammad H. Zaheer🇺🇸

    In a broad class of theories, the accumulation of ultralight dark matter (ULDM) with particles of mass $10^{-22}\text{eV}<m_{\varphi }<1\text{eV}$ leads the to formation of long-lived bound states known as boson stars. When the ULDM exhibits self-interactions, prodigious bursts of energy carried by relativistic bosons are released from collapsing boson stars in bosenova explosions. We extensively explore the potential reach of terrestrial and space-based experiments for detecting transient signatures of emitted relativistic bursts of scalar particles, including ULDM coupled to photons, electrons, and gluons, capturing a wide range of motivated theories. For the scenario of relaxion ULDM, we demonstrate that upcoming experiments and technology such as nuclear clocks as well as space-based interferometers will be able to sensitively probe orders of magnitude in the ULDM coupling-mass parameter space, challenging to study otherwise, by detecting signatures of transient bosenova events. Our analysis can be readily extended to different scenarios of relativistic scalar particle emission.

    hep-phastro-ph.COastro-ph.HEphysics.atom-ph+1PRD(2024)·28 citations
17. 17*

    Reheating constraints and consistency relations of the Starobinsky model and some of its generalizations

    Marcos A. G. Garcia🇲🇽 · Gabriel Germán🇲🇽 · R. Gonzalez Quaglia🇲🇽 · A. M. Moran Colorado🇲🇽

    Building on the success of the Starobinsky model in describing the inflationary period of the universe, we investigate two simple generalizations of this model and their constraints imposed by the reheating epoch. The first generalization takes the form $R^{2p}$, while the second is the $\alpha$-Starobinsky model. We first focus on the case where $p=1$ or equivalently, $\alpha =1$, which corresponds to the original Starobinsky model. We derive exact consistency relations between observables and cosmological quantities, without neglecting any terms, and impose the reheating condition $0<{\omega }_{re}<0.25$, where ${\omega }_{re}$ is the equation of state parameter at the end of reheating. This allows us to obtain new bounds for $n_s$ and $r$ that satisfy this condition and apply them to other observables and cosmological quantities. We repeat this process for the cases where $p\ne 1$ and $\alpha \ne 1$ and find that these generalizations only result in minor modifications of the Starobinsky model, including the potential and the bounds on observables and cosmological quantities.

    ↳ astro-ph.COgr-qchep-phJCAP(2023)·19 citations
18. 18*

    Holography for the Trace Anomaly Action

    Gregory Gabadadze🇺🇸 · Massimo Porrati🇺🇸

    A recently proposed effective action for the trace anomaly describes a tensor-scalar theory that is weakly coupled up to a certain high energy scale, where it becomes strongly interacting. Its ultraviolet completion is obtained by coupling to gravity a quantum field theory in which conformal invariance is spontaneously broken. In this paper, we show that if the field theory that gives rise to the trace anomaly is a large $N_c$ conformal field theory, then the trace anomaly action has a completion above the strong scale in a holographic Randall-Sundrum two-brane theory, with the radion as a low energy remnant of the spontaneously broken conformal symmetry. Furthermore, we note that the sub-leading $N_c$ terms can be derived by adding localized fields to the UV brane, so that the theory remains weakly coupled. The sub-leading terms are also obtained by introducing the Weyl squared terms in the 5D bulk. These, however, exhibit strongly coupled behavior at the respective sub-Planckian energy scales.

    ↳ hep-thgr-qchep-phPRD(2023)·3 citations
19. 19*

    Diffuse neutrino background from past core-collapse supernovae

    Shin'ichiro Ando🇳🇱 · Nick Ekanger🇺🇸 · Shunsaku Horiuchi🇺🇸 · Yusuke Koshio🇯🇵

    Core-collapse supernovae are among the most powerful explosions in the universe, emitting thermal neutrinos that carry away the majority of the gravitational binding energy released. These neutrinos create a diffuse supernova neutrino background (DSNB), one of the largest energy budgets among all radiation backgrounds. Detecting the DSNB is a crucial goal of modern high-energy astrophysics and particle physics, providing valuable insights in both core-collapse modeling, neutrino physics, and cosmic supernova rate history. In this review, we discuss the key ingredients of DSNB calculation and what we can learn from future detections, including black-hole formation and non-standard neutrino interactions. Additionally, we provide an overview of the latest updates in neutrino experiments, which could lead to the detection of the DSNB in the next decade. With the promise of this breakthrough discovery on the horizon, the study of DSNB holds enormous potential for advancing our understanding of the Universe.

    ↳ astro-ph.HEastro-ph.COhep-phProceedings of the Japan Academy, Series …·34 citations
20. 20*

    Universal rapidity scaling of entanglement entropy inside hadrons from conformal invariance

    Umut Gürsoy🇳🇱 · Dmitri E. Kharzeev🇺🇸 · Juan F. Pedraza🇪🇸

    When a hadron is probed at high energy, a nontrivial quantum entanglement entropy inside the hadron emerges due to the lack of complete information about the hadron wave function extracted from this measurement. In the high-energy limit, the hadron becomes a maximally entangled state, with a linear dependence of entanglement entropy on rapidity, as has been found in a recent analysis based on parton description. In this paper, we use an effective conformal field theoretic description of hadrons on the light cone to show that the linear dependence of the entanglement entropy on rapidity found in parton description is a general consequence of approximate conformal invariance and does not depend on the assumption of weak coupling. Our result also provides further evidence for a duality between the parton and string descriptions of hadrons.

    ↳ hep-thhep-phnucl-thPRD(2024)·18 citations
21. 21*

    The NANOGrav 15-year Data Set: Search for Signals from New Physics

    Adeela Afzal🇵🇰 · Gabriella Agazie🇺🇸 · Akash Anumarlapudi🇺🇸 · Anne M. Archibald🇬🇧 · Zaven Arzoumanian🇺🇸 · Paul T. Baker🇺🇸 · Bence Bécsy🇺🇸 · Jose Juan Blanco-Pillado🇪🇸 · Laura Blecha🇺🇸 · Kimberly K. Boddy🇺🇸 · Adam Brazier🇺🇸 · Paul R. Brook🇬🇧 and 111 other authors

    The 15-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations of this signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, cosmic strings, and domain walls. We find that, with the exception of stable cosmic strings of field theory origin, all these models can reproduce the observed signal. When compared to the standard interpretation in terms of inspiraling supermassive black hole binaries (SMBHBs), many cosmological models seem to provide a better fit resulting in Bayes factors in the range from 10 to 100. However, these results strongly depend on modeling assumptions about the cosmic SMBHB population and, at this stage, should not be regarded as evidence for new physics. Furthermore, we identify excluded parameter regions where the predicted GW signal from cosmological sources significantly exceeds the NANOGrav signal. These parameter constraints are independent of the origin of the NANOGrav signal and illustrate how pulsar timing data provide a new way to constrain the parameter space of these models. Finally, we search for deterministic signals produced by models of ultralight dark matter (ULDM) and dark matter substructures in the Milky Way. We find no evidence for either of these signals and thus report updated constraints on these models. In the case of ULDM, these constraints outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phApJL(2023)·1130 citations
22. 22*

    The second data release from the European Pulsar Timing Array: VI. Challenging the ultralight dark matter paradigm

    Clemente Smarra🇮🇹 · Boris Goncharov🇮🇹 · Enrico Barausse🇮🇹 · J. Antoniadis🇬🇷 · S. Babak🇫🇷 · A.-S. Bak Nielsen🇩🇪 · C. G. Bassa🇳🇱 · A. Berthereau🇫🇷 · M. Bonetti🇮🇹 · E. Bortolas🇮🇹 · P. R. Brook🇬🇧 · M. Burgay🇮🇹 and 59 other authors

    Pulsar Timing Array experiments probe the presence of possible scalar or pseudoscalar ultralight dark matter particles through decade-long timing of an ensemble of galactic millisecond radio pulsars. With the second data release of the European Pulsar Timing Array, we focus on the most robust scenario, in which dark matter interacts only gravitationally with ordinary baryonic matter. Our results show that ultralight particles with masses $10^{-24.0}\text{eV}\lesssim m\lesssim 10^{-23.3}\text{eV}$ cannot constitute $100\%$ of the measured local dark matter density, but can have at most local density $\rho \lesssim 0.3$ GeV/cm${}^3$.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAgr-qc+1PRL(2023)·127 citations
23. 23*

    The invisible low-frequency gravitons and the audio band

    Massimo Giovannini🇮🇹

    The low-frequency gravitons correspond to typical wavelengths that left the Hubble radius during the early inflationary stages of expansion and reentered after matter radiation equality. Consequently the temperature and the polarization anisotropies of the cosmic microwave background constrain the tensor-to-scalar-ratio in the aHz region but since the audio band and the MHz domain are sensitive to the post-inflationary expansion rate, the low-frequency determinations of the tensor-to-scalar-ratio can be combined with the high-frequency constraints. In this framework we examine the possibility that the low-frequency gravitons remain invisible in the aHz region but are still potentially detectable at much higher frequencies. Because the number of $e$-folds associated with the exit of the cosmic microwave background wavelengths depends both on the slow-roll parameters and on the total expansion rate after inflation, this approach leads to a set of lower bounds on the tensor-to-scalar-ratio.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2023)·12 citations
24. 24*

    Constraining MeV-scale axion-like particles with Fermi-LAT observations of SN 2023ixf

    Eike Ravensburg · Pierluca Carenza🇸🇪 · Christopher Eckner🇫🇷 · Ariel Goobar🇸🇪

    The Fermi-LAT observations of SN 2023ixf, a Type II supernova in the nearby Pinwheel Galaxy, Messier 101 (M101), presents us with an excellent opportunity to constrain MeV-scale Axion-Like Particles (ALPs). By examining the photon decay signature from heavy ALPs that could be produced in the explosion, the existing constraints on the ALP-photon coupling can be improved, under optimistic assumptions, by up to a factor of $\sim 2$ for masses $m_a\lesssim 3$ MeV. Under very conservative assumptions, we find a bound that is slightly weaker than the existing ones for $m_a\lesssim 0.5$ MeV. The exact reach of these searches depends mostly on properties of the SN progenitor. This study demonstrates the relevance of core-collapse supernovae, also beyond the Magellanic Clouds, as probes of fundamental physics.

    ↳ astro-ph.HEhep-phPRD(2024)·37 citations
25. 25*

    Free fermionic webs of heterotic T-folds

    Alon E. Faraggi🇬🇧 · Stefan Groot Nibbelink · Benjamin Percival🇬🇧

    Moduli stabilisation is key to obtaining phenomenologically viable string models. Non-geometric compactifications, like T-duality orbifolds (T-folds), are capable of freezing many moduli. However, in this Letter we emphasise that T-folds, admitting free fermionic descriptions, can be associated with a large number of different T-folds with varying number of moduli, since the fermion pairings for bosonisation are far from unique. Consequently, in one description a fermionic construction might appear to be asymmetric, and hence non-geometric, while in another it admits a symmetric orbifold description. We introduce the notion of intrinsically asymmetric T-folds for fermionic constructions that do not admit any symmetric orbifold description after bosonisation. Finally, we argue that fermion symmetries induce mappings in the bosonised description that extend the T-duality group.

    ↳ hep-thhep-phPRD(2024)·8 citations
26. 26*

    Influence of local structure on relic neutrino abundances and anisotropies

    Fabian Zimmer🇳🇱 · Camila A. Correa🇳🇱 · Shin'ichiro Ando🇳🇱

    Gravitational potentials of the Milky Way and extragalactic structures can influence the propagation of the cosmic neutrino background (CNB). Of particular interest to future CNB observatories, such as PTOLEMY, is the CNB number density on Earth. In this study, we have developed a simulation framework that maps the trajectories of relic neutrinos as they move through the local gravitational environment. The potentials are based on the dark matter halos found in state-of-the-art cosmological N-body simulations, resulting in a more nuanced and realistic input than the previously employed analytical models. We find that the complex dark matter distributions, along with their dynamic evolution, influence the abundance and anisotropies of the CNB in ways unaccounted for by earlier analytical methods. Importantly, these cosmological simulations contain multiple instances of Milky Way-like halos that we employ to model a variety of gravitational landscapes. Consequently, we notice a variation in the CNB number densities that can be primarily attributed to the differences in the masses of these individual halos. For neutrino masses between $0.01$ and $0.3$ eV, we note clustering factors within the range of $1+\mathcal{O}(10^{-3})$ to $1+\mathcal{O}(1)$. Furthermore, the asymmetric nature of the underlying dark matter distributions within the halos results in not only overdense, but intriguingly, underdense regions within the full-sky anisotropy maps. Gravitational clustering appears to have a significant impact on the angular power spectra of these maps, leading to orders of magnitude more power on smaller scales beyond multipoles of $\ell =3$ when juxtaposed against predictions by primordial fluctuations. We discuss how our results reshape our understanding of relic neutrino clustering and how this might affect observability of future CNB observatories such as PTOLEMY.

    ↳ astro-ph.COhep-phJCAP(2023)·24 citations
27. 27*

    Double Kerr-Schild spacetimes and the Newman-Penrose map

    Kara Farnsworth🇨🇭 · Michael Graesser🇺🇸 · Gabriel Herczeg🇺🇸

    The Newman-Penrose map, which is closely related to the classical double copy, associates certain exact solutions of Einstein's equations with self-dual solutions of the vacuum Maxwell equations. Here we initiate an extension of the Newman-Penrose map to a broader class of spacetimes. As an example, we apply principles from the Newman-Penrose map to associate a self-dual gauge field to the Kerr-Taub-NUT-(A)dS spacetime and we show that the result agrees with previously studied examples of classical double copies. The corresponding field strength exhibits a discrete electric-magnetic duality that is distinct from its (Hodge star) self-dual property.

    ↳ hep-thgr-qchep-phJHEP(2023)·24 citations
28. 28*

    Superradiance: Axionic Couplings and Plasma Effects

    Thomas F.M. Spieksma🇩🇰 · Enrico Cannizzaro🇮🇹 · Taishi Ikeda🇩🇰 · Vitor Cardoso🇩🇰 · Yifan Chen🇩🇰

    Spinning black holes can transfer a significant fraction of their energy to ultralight bosonic fields via superradiance, condensing them in a co-rotating structure or "cloud". This mechanism turns black holes into powerful particle detectors for bosons with extremely feeble interactions. To explore its full potential, the couplings between such particles and the Maxwell field in the presence of plasma need to be understood. In this work, we study these couplings using numerical relativity. We first focus on the coupled axion-Maxwell system evolving on a black hole background. By taking into account the axionic coupling concurrently with the growth of the cloud, we observe for the first time that a new stage emerges: that of a stationary state where a constant flux of electromagnetic waves is fed by superradiance, for which we find accurate analytical estimates. Moreover, we show that the existence of electromagnetic instabilities in the presence of plasma is entirely controlled by the axionic coupling; even for dense plasmas, an instability is triggered for high enough couplings.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2023)·53 citations
29. 29*

    Entropy Bounds and the Species Scale Distance Conjecture

    José Calderón-Infante🇨🇭 · Alberto Castellano🇪🇸 · Alvaro Herráez🇫🇷 · Luis E. Ibáñez🇪🇸

    The Swampland Distance Conjecture (SDC) states that, as we move towards an infinite distance point in moduli space, a tower of states becomes exponentially light with the geodesic distance in any consistent theory of Quantum Gravity. Although this fact has been tested in large sets of examples, it is fair to say that a bottom-up justification that explains both the geodesic requirement and the exponential behavior has been missing so far. In the present paper we address this issue by making use of the Covariant Entropy Bound as applied to the EFT. When applied to backgrounds of the Dynamical Cobordism type in theories with a moduli space, we are able to recover these main features of the SDC. Moreover, this naturally leads to universal lower and upper bounds on the 'decay rate' parameter ${\lambda }_{\text{sp}}$ of the species scale, that we propose as a convex hull condition under the name of Species Scale Distance Conjecture (SSDC). This is in contrast to already proposed universal bounds, that apply to the SDC parameter of the lightest tower. We also extend the analysis to the case in which asymptotically exponential potentials are present, finding a nice interplay with the asymptotic de Sitter conjecture. To test the SSDC, we study the convex hull that encodes the (asymptotic) moduli dependence of the species scale. In this way, we show that the SSDC is the strongest bound on the species scale exponential rate which is preserved under dimensional reduction and we verify it in M-theory toroidal compactifications.

    ↳ hep-thgr-qchep-phJHEP(2024)·76 citations
30. 30*

    The incompleteness of the experimental searches for vector-like leptons at CERN

    Feyza Baspehlivan🇹🇷 · Burak Dagli🇹🇷 · Hatice Duran Yildiz🇹🇷 · Saleh Sultansoy🇹🇷

    There are strong phenomenological arguments favoring the existence of vector-like leptons and quarks in nature. In spite of extensive studies conducted in search of vector-like quarks, there are only a limited number of experimental studies on vector-like leptons. Moreover, these searches do not include all possible decay modes of vector-like leptons. Therefore, the analyses done so far are incomplete. In this letter, we highlight decay channels that are not covered by different experimental analyses, with a focus on L3, ATLAS, and CMS results. We argue that experimental analyses should be redone considering these shortcomings.

    ↳ hep-exhep-ph1 citation

* 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.