Thu·Jul 22, 2021Thursday·July 22, 2021

1. 01*

   Flavor-Violating Higgs Decays and Stellar Cooling Anomalies in Axion Models

   Marcin Badziak🇵🇱 · Giovanni Grilli di Cortona🇮🇹 · Mustafa Tabet🇩🇪 · Robert Ziegler🇩🇪

   We study a class of DFSZ-like models for the QCD axion that can address observed anomalies in stellar cooling. Stringent constraints from SN1987A and neutron stars are avoided by suppressed couplings to nucleons, while axion couplings to electrons and photons are sizable. All axion couplings depend on few parameters that also control the extended Higgs sector, in particular lepton flavor-violating couplings of the Standard Model-like Higgs boson $h$. This allows us to correlate axion and Higgs phenomenology, and we find that that $\mathrm{BR}(h\to \tau e)$ can be as large as the current experimental bound of 0.22%, while $\mathrm{BR}(h\to \mu \mu )$ can be larger than in the Standard Model by up to 70%. Large parts of the parameter space will be tested by the next generation of axion helioscopes such as the IAXO experiment.

   hep-phhep-exJHEP(2021)·20 citations
2. 02*

   Next-to SV resummed Drell-Yan cross section beyond leading-logarithm

   A. H. Ajjath · Pooja Mukherjee🇮🇳 · V. Ravindran🇮🇳 · Aparna Sankar🇮🇳 · Surabhi Tiwari🇮🇳

   We present the resummed predictions for inclusive cross section for Drell-Yan (DY) production up to next-to-next-to leading logarithmic ($\overline{\mathrm{NNLL}}$) accuracy taking into account both soft virtual (SV) and next-to SV (NSV) threshold logarithms. We restrict ourselves to resummed contributions only from quark anti-quark ($q\bar{q}$) initiated channels. The resummation is performed in Mellin-$N$ space. We derive the $N$-dependent coefficients and the $N$-independent constants to desired accuracy for our study. The resummed results are matched through the minimal prescription procedure with the fixed order results. We find that the resummation, taking into account the NSV terms, appreciably increases the cross section while decreasing the sensitivity to renormalisation scale. \textcolor{black}{We observe that, at 13 TeV LHC energies, the SV+NSV resummation at $\overline{\mathrm{NLL}}(\overline{\mathrm{NNLL}})$ gives about 8\% (2\%) corrections respectively to the NLO (NNLO) results for the considered $Q$ range: 150-3500 GeV}. In addition, the absence of quark gluon initiated contributions to NSV part in the resummed terms leaves large factorisation scale dependence indicating their importance at NSV level. We also study the numerical impact of $N$-independent constants and explore the ambiguity involved in exponetiating them. Finally we present our predictions for the neutral Drell-Yan process at various center of mass of energies.

   hep-phhep-exEPJC(2022)·34 citations
3. 03*

   Muon $g-2$ in $U(1{)}_{\mu -\tau }$ Symmetric Gauged Radiative Neutrino Mass Model

   Dong Woo Kang🇰🇷 · Jongkuk Kim🇰🇷 · Hiroshi Okada🇰🇷

   We explore muon anomalous magnetic moment (muon $g-2$) in a scotogenic neutrino model with a gauged lepton number symmetry $U(1{)}_{\mu -\tau }$. In this model, a dominant muon $g-2$ contribution comes not from an additional gauge sector but from a Yukawa sector. In our numerical $\Delta {\chi }^2$ analysis, we show that our model is in favor of normal hierarchy with some features. We demonstrate one benchmark point, satisfying muon $g-2$ at the best fit value $25.1\times 10^{-10}$.

   hep-phPLB(2021)·14 citations
4. 04*

   Gamma-ray line from electroweakly interacting non-abelian spin-1 dark matter

   Tomohiro Abe🇯🇵 · Motoko Fujiwara🇯🇵 · Junji Hisano🇯🇵 · Kohei Matsushita🇯🇵

   We study gamma-ray line signatures from electroweakly interacting non-abelian spin-1 dark matter (DM). In this model, $Z_2$-odd spin-1 particles including a DM candidate have the SU(2)${}_L$ triplet-like features, and the Sommerfeld enhancement is relevant in the annihilation processes. We derive the annihilation cross sections contributing to the photon emission and compare with the SU(2)${}_L$ triplet fermions, such as Wino DM in the supersymmetric Standard Model. The Sommerfeld enhancement factor is approximately the same in both systems, while our spin-1 DM predicts the larger annihilation cross sections into $\gamma \gamma /Z\gamma$ modes than those of the Wino by $\frac{38}{9}$. This is because a spin-1 DM pair forms not only $J=0$ but also $J=2$ partial wave states where $J$ denotes the total spin angular momentum. Our spin-1 DM also has a new annihilation mode into $Z_2$-even extra heavy vector and photon, $Z^{\prime }\gamma$. For this mode, the photon energy depends on the masses of DM and the heavy vector, and thus we have a chance to probe the mass spectrum. The latest gamma-ray line search in the Galactic Center region gives a strong constraint on our spin-$1$ DM. We can probe the DM mass for $\lesssim 25.3$TeV by the Cherenkov Telescope Array experiment even if we assume a conservative DM density profile.

   hep-phastro-ph.HEJHEP(2021)·4 citations
5. 05*

   Strong-field Breit-Wheeler pair production with bremsstrahlung gamma-rays in the perturbative-to-nonperturbative transition regime

   A. Eckey🇩🇪 · A.B. Voitkiv🇩🇪 · C. Müller🇩🇪

   Photoproduction of electron-positron pairs by bremsstrahlung gamma-rays propagating through a high-intensity optical laser wave is studied. By calculating total pair production yields as well as energy and angular distributions of the produced particles for a range of laser intensities, we analyze the influence that the broad frequency spectrum of bremsstrahlung exerts on the properties of the process in the transition region between the perturbative and non-perturbative interaction regimes. In particular, we demonstrate a continuous shifting of the mainly contributing interval of bremsstrahlung frequencies during the course of the transition and indicate characteristic signatures of the laser-dressed particle mass.

   hep-phPRA(2022)·13 citations
6. 06*

   Light mesons around critical end points in $T-{\mu }_B-{\mu }_I-eB$ space

   Luyang Li🇨🇳 · Shijun Mao🇨🇳

   Light mesons $(\sigma ,{\pi }^0,{\pi }^{\pm })$ are investigated in $T-{\mu }_B-{\mu }_I-eB$ space by using a two-flavor NJL model, which are related to the chiral symmetry restoration and pion superfluid phase transition. In $T-{\mu }_B-eB$ space, during the chiral restoration process, the mass of pseudo-Goldstone mode ${\pi }^0$ keeps increasing, together with the sudden mass jump. At the critical end point region, ${\pi }^0$ meson has a very sharp but continuous mass increase, together with a sudden mass jump at the Mott transition, and in the first order chiral phase transition region nearby, we observe twice ${\pi }^0$ mass jumps, induced by the Mott transition and quark mass jump, respectively. The mass of Higgs mode $\sigma$ first decreases and then increases associated with the chiral symmetry restoration, and shows a jump at the first order chiral phase transition. We plot the chiral phase diagram in terms of the change of quark mass, the Mott transition of ${\pi }^0$ and the minimum mass of $\sigma$. Due to the explicit breaking of chiral symmetry in physical case, the chiral restoration phase boundaries in $T-{\mu }_B$ plane from the order parameter and meson side are different from each other. In $T-{\mu }_I$ plane, the competition between pion superfluid phase transition and chiral symmetry restoration under magnetic fields is studied in terms of the Goldstone mode ${\pi }^{+}$ and the pseudo-Goldstone mode ${\pi }^0$. The separation of the two phase boundaries is enhanced by the external magnetic field. Different from the twice mass jumps of ${\pi }^0$ in the first order chiral phase transition region, the ${\pi }^{+}$ meson displays several mass jumps in the chiral crossover region. At the critical end point, ${\pi }^{+}$ also shows very sharp but continuous mass changes, together with a mass jump at the Mott transition.

   hep-phnucl-thCPC(2022)·1 citation
7. 07*

   $R_{K^{(\ast )}}$ from RPV-SUSY sneutrinos

   Debjyoti Bardhan🇮🇱 · Diptimoy Ghosh🇮🇳 · Divya Sachdeva🇮🇳

   We analyze the lepton flavor universality violation (LFV) in process $b\to s{\ell }^{+}{\ell }^{-}$ in an R-parity violating supersymmetric (RPV-SUSY) scenario. The most recent update on $\text{rk}$ from the LHCb collaboration suggests approximately $3.1\sigma$ deviation from the Standard Model predictions, strengthening the case of LFV New Physics. In this work, we show that $R_{K^{(\ast )}}$ anomaly can be addressed via only sneutrinos within the framework of R-parity violating interactions assuming phenomenologically viable values of the couplings. While our proposed solution is by no means the only solution to these anomalies, it is a phenomenologically plausible one and, notably, quite a minimal one in the context of RPV-SUSY.

   hep-phNPB(2023)·13 citations
8. 08*

   On non-conformal kinetic theory and hydrodynamics for Bjorken flow

   Sunil Jaiswal (1) · Chandrodoy Chattopadhyay (2) · Lipei Du (2) · Ulrich Heinz (2) · Subrata Pal (1) ((1) TIFR · Mumbai · (2) Ohio State U.)

   Using and comparing kinetic theory and second-order Chapman-Enskog hydrodynamics, we study the non-conformal dynamics of a system undergoing Bjorken expansion. We use the concept of `free-streaming fixed lines' for scaled shear and bulk stresses in non-conformal kinetic theory and hydrodynamics, and show that these `fixed lines' behave as early-time attractors and repellors of the evolution. In the conformal limit, the free-streaming fixed lines reduce to the well-known fixed points of conformal Bjorken dynamics. A new fixed point in the free streaming regime is identified which lies at the intersection of these fixed lines. Contrary to the conformal scenario, both kinetic theory and hydrodynamics predict the absence of attractor behavior in the normalised shear stress channel. In kinetic theory a far-off-equilibrium attractor is found for the normalised effective longitudinal pressure, driven by rapid longitudinal expansion. Second-order viscous hydrodynamics fails to accurately describe this attractor. From a thorough analysis of the free-streaming dynamics in Chapman-Enskog hydrodynamics we conclude that this failure results from an inaccurate approximation of the fixed lines and a related incorrect description of the nature of the fixed point. A modified anisotropic hydrodynamic description is presented that provides excellent agreement with kinetic theory results and reproduces the far-from-equilibrium attractor for the scaled longitudinal pressure.

   hep-phnucl-thPRC(2022)·58 citations
9. 09*

   General non-leptonic $\Delta F=1$ WET at the NLO in QCD

   Jason Aebischer🇺🇸 · Christoph Bobeth🇩🇪 · Andrzej J. Buras🇩🇪 · Jacky Kumar🇩🇪 · Mikołaj Misiak🇵🇱

   We reconsider the complete set of four-quark operators in the Weak Effective Theory (WET) for non-leptonic $\Delta F=1$ decays that govern $s\to d$ and $b\to d,s$ transitions in the Standard Model (SM) and beyond, at the Next-to-Leading Order (NLO) in QCD. We discuss cases with different numbers $N_f$ of active flavours, intermediate threshold corrections, as well as the issue of transformations between operator bases beyond leading order to facilitate the matching to high-energy completions or the Standard Model Effective Field Theory (SMEFT) at the electroweak scale. As a first step towards a SMEFT NLO analysis of $K\to \pi \pi$ and non-leptonic $B$-meson decays, we calculate the relevant WET Wilson coefficients including two-loop contributions to their renormalization group running, and express them in terms of the Wilson coefficients in a particular operator basis for which the one-loop matching to SMEFT is already known.

   hep-phhep-exhep-latJHEP(2021)·22 citations
10. 10*

    An ultraviolet completion for the Scotogenic model

    Pablo Escribano🇪🇸 · Avelino Vicente🇪🇸

    The Scotogenic model is an economical scenario that generates neutrino masses at the 1-loop level and includes a dark matter candidate. This is achieved by means of an ad-hoc ${\mathbb{Z}}_2$ symmetry, which forbids the tree-level generation of neutrino masses and stabilizes the lightest ${\mathbb{Z}}_2$-odd state. Neutrino masses are also suppressed by a quartic coupling, usually denoted by ${\lambda }_5$. While the smallness of this parameter is natural, it is not explained in the context of the Scotogenic model. We construct an ultraviolet completion of the Scotogenic model that provides a natural explanation for the smallness of the ${\lambda }_5$ parameter and induces the ${\mathbb{Z}}_2$ parity as the low-energy remnant of a global $\mathrm{U}(1)$ symmetry at high energies. The low-energy spectrum contains, besides the usual Scotogenic states, a massive scalar and a massless Goldstone boson, hence leading to novel phenomenological predictions in flavor observables, dark matter physics and colliders.

    hep-phPLB(2021)·13 citations
11. 11*

    Supersymmetric Alignment Models for $(g-2{)}_{\mu }$

    Yuichiro Nakai🇨🇳 · Matthew Reece🇺🇸 · Motoo Suzuki🇨🇳

    Hierarchical masses of quarks and leptons are addressed by imposing horizontal symmetries. In supersymmetric Standard Models, the same symmetries play a role in suppressing flavor violating processes induced by supersymmetric particles. Combining the idea of spontaneous CP violation to control contributions to electric dipole moments (EDMs), the mass scale of supersymmetric particles can be lowered. We present supersymmetric models with $U(1)$ horizontal symmetries and discuss CP and flavor constraints. Models with two $U(1)$ symmetries are found to give a viable solution to the muon $g-2$ anomaly. Interestingly, the parameter space to explain the anomaly will be probed by future electron EDM experiments.

    hep-phJHEP(2021)·24 citations
12. 12*

    Z lepton flavour violation as a probe for new physics at future $e^{+}{e}^{-}$ colliders

    Lorenzo Calibbi🇨🇳 · Xabier Marcano🇩🇪 · Joydeep Roy🇮🇳

    In this work we assess the potential of discovering new physics by searching for lepton-flavour-violating (LFV) decays of the $Z$ boson, $Z\to {\ell }_i{\ell }_j$, at the proposed circular $e^{+}{e}^{-}$ colliders CEPC and FCC-ee. Both projects plan to run at the $Z$-pole as a Tera Z factory, i.e., collecting $\mathcal{O}\left(10^{12}\right)$ $Z$ decays. In order to discuss the discovery potential in a model-independent way, we revisit the LFV $Z$ decays in the context of the Standard Model effective field theory and study the indirect constraints from LFV $\mu$ and $\tau$ decays on the operators that can induce $Z\to {\ell }_i{\ell }_j$. We find that, while the $Z\to \mu e$ rates are beyond the expected sensitivities, a Tera Z factory is promising for $Z\to \tau \ell$ decays, probing New Physics at the same level of future low-energy LFV observables.

    hep-phhep-exEPJC(2021)·68 citations
13. 13*

    Evolution of decaying particles and decay products in various scenarios for the future expansion of the universe

    Cameron E. Norton🇺🇸 · Robert J. Scherrer🇺🇸

    We examine nonrelativistic particles that decay into relativistic products in big rip, little rip, and pseudo-rip models for the future evolution of the universe. In contrast to decays that occur in standard $\Lambda$CDM, the evolution of the ratio $r$ of the energy density of the relativistic decay products to the energy density of the initially decaying particles can decrease with time in all of these models. In big rip and little rip models, $r$ always goes to zero asymptotically, while this ratio evolves to infinity or a constant in pseudo-rip models.

    ↳ astro-ph.COhep-phPRD(2021)·0 citations
14. 14*

    The spectrum of tensor perturbations in warm inflation

    Yue Qiu🇺🇸 · Lorenzo Sorbo🇺🇸

    We compute the spectrum of tensor perturbations in warm inflation. We find that the spectrum, besides the standard component $\propto H^2/M_P^2$ associated to the amplification of the tensor vacuum fluctuations, acquires a component $\propto {\ell }_{\mathrm{mfp}}{T}^5/M_P^4$, where ${\ell }_{\mathrm{mfp}}$ and $T$ are respectively the mean free path and the temperature of the thermal degrees of freedom. The new contribution is due to the direct production of gravitational waves by the thermal bath, and can exceed the standard one in a viable region of parameter space. This contribution is dominated by thermal fluctuations at scales longer than ${\ell }_{\mathrm{mfp}}$.

    ↳ astro-ph.COhep-phhep-thPRD(2021)·18 citations
15. 15*

    CEPC Research Report: Higgs Physics Analysis

    Manqi Ruan🇨🇳 · Yaquan Fang🇨🇳 · Gang Li🇨🇳 · Dan Yu🇨🇳

    In November 2018, the CEPC released the Conceptual Design Report (CDR) with the physics potential investigation and the analysis about different detector concepts. Since then, intensive researches on the Higgs Physics at the CEPC have been progressed. The run at top thresholds are also taken into consideration and the physics potential around the center-of-mass energy of 360GeV is studied. The $ttH$ channel information boost the precision of Higgs width measurement by a factor of 2 with respect to 240 GeV Higgs Runs. Different Higgs decay modes are analyzed in the CEPC Higgs factory at the center-of-mass energy of 240GeV, including Higgs to b/c/g and Higgs to $\tau \tau$, which improves the Higgs measurement. Advanced analysis technologies are developed and applied in the analysis, such as jet reconstruction and lepton identification in jets. New interpretations are under developing to improve the performance.

    ↳ hep-exhep-ph3 citations
16. 16*

    Future Physics Prospects with the CMS Detector at the High-Luminosity LHC

    Conor Henderson (for the CMS Collaboration)🇺🇸

    The High-Luminosity Large Hadron Collider is expected to deliver up to 3000 fb${}^{-1}$ of proton-proton collisions at 14 TeV center-of-mass energy. We present prospects for selected heavy-ion, Standard Model and Higgs sector measurements with the CMS detector at the HL-LHC, and discuss potential sensitivity to several beyond-Standard Model new physics scenarios.

    ↳ hep-exhep-phSciPost Phys.Proc.(2022)·5 citations
17. 17*

    Nonexistence of supersymmetry breaking counterexamples to the Nelson-Seiberg theorem

    Zhenhuan Li🇨🇳 · Zheng Sun🇨🇳

    Counterexample models to the Nelson-Seiberg theorem have been discovered, and their features have been studied in previous literature. All currently known counterexamples have generic superpotentials respecting the R-symmetry, and more R-charge 2 fields than R-charge 0 fields. But they give supersymmetric vacua with spontaneous R-symmetry breaking, thus violate both the Nelson-Seiberg theorem and its revisions. This work proves that the other type of counterexamples do not exist. When there is no R-symmetry, or there are no more R-charge 2 fields than R-charge 0 fields in models with R-symmetries, generic superpotentials always give supersymmetric vacua. There exists no specific arrangement of R-charges or non-R symmetry representations which makes a counterexample with a supersymmetry breaking vacuum. This nonexistence theorem contributes to a refined classification of R-symmetric Wess-Zumino models.

    ↳ hep-thhep-phJHEP(2021)·7 citations
18. 18*

    The BH-PSR Gravitational Molecule

    Tao Liu🇨🇳 · Kun-Feng Lyu🇨🇳

    While an axion-clouded black hole (BH) encounters a pulsar (PSR) or has a PSR companion, a "gravitational molecule" can be formed. In such a system, the axion cloud evolves at the binary hybrid orbitals, as it happens at microscopic level to electron cloud in a chemical molecule. To demonstrate this picture, we develop a semi-analytical formalism using the method of linear combination of atomic orbitals with an adiabatic approximation. An oscillating axion-cloud profile and a perturbed binary rotation, together with unique and novel detection signals, are then predicted. Remarkably, the proposed PSR timing and polarization observables, namely the oscillation of periastron time shift and the birefringence with multiple modulations, correlate in pattern, and thus can be properly combined to strengthen the detection.

    ↳ astro-ph.HEhep-phhep-th13 citations
19. 19*

    Singlet channel scattering in a Composite Higgs model on the lattice

    Vincent Drach🇬🇧 · Patrick Fritzsch🇮🇪 · Antonio Rago🇬🇧 · Fernando Romero-López🇪🇸

    We present the first calculation of the scattering amplitude in the singlet channel beyond QCD. The calculation is performed in $SU(2)$ gauge theory with $N_f=2$ fundamental Dirac fermions and based on a finite-volume scattering formalism. The theory exhibits a $SU(4)\to Sp(4)$ chiral symmetry breaking pattern that is used to design minimal composite Higgs models currently tested at the LHC. Our results show that, for the range of underlying fermion mass considered, the lowest flavour singlet state is stable.

    ↳ hep-lathep-phEPJC(2022)·31 citations
20. 20*

    Second order cumulants of conserved charge fluctuations revisited I. Vanishing chemical potentials

    D. Bollweg🇩🇪 · J. Goswami🇩🇪 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · P. Scior🇺🇸

    We update lattice QCD results for second order cumulants of conserved charge fluctuations and correlations at non-zero temperature and vanishing values of the conserved charge chemical potentials. We compare these results to hadron resonance gas calculations with and without excluded volume terms as well as S-matrix results in the hadronic phase of QCD, and comment on their current limitations. We, furthermore, use these results to characterize thermal conditions in the vicinity of the pseudo-critical line of the chiral transition in QCD. We argue that the ratio of strange to baryon chemical potentials is a robust observable that, on the one hand, deviates only little from hadron resonance gas results, but, on the other hand, is very sensitive to the spectrum of strange baryon resonances.

    ↳ hep-lathep-phnucl-thPRD(2021)·94 citations
21. 21*

    Transverse spin asymmetries for inclusive ${\rho }^0$ production in SIDIS at COMPASS

    A. Kerbizi (for the COMPASS Collaboration)🇮🇹

    The production of vector mesons in SIDIS is a particularly interesting channel to study the polarized fragmentation and related phenomena. Preliminary COMPASS results for the first measurement of inclusive ${\rho }^0$ Collins and Sivers transverse-spin asymmetries are presented here for the first time. The analysis is based on the data-set collected by COMPASS in $2010$ using a $160\mathrm{GeV}/c$ ${\mu }^{+}$ beam and a transversely polarized $N{H}_3$ target. The asymmetries are extracted as function of Bjorken-$x$, of the total transverse momentum of the oppositely charged hadron pair and of the fraction of available energy $z$ carried by the pair. Indications for positive Collins and Sivers asymmetries are obtained as expected from models.

    ↳ hep-exhep-phSciPost Phys.Proc.(2022)·3 citations
22. 22*

    Light-Front Transverse Momentum Distributions for $\mathcal{J}$=1/2 Hadronic Systems in Valence Approximation

    Rocco Alessandro🇮🇹 · Alessio Del Dotto🇮🇹 · Emanuele Pace🇮🇹 · Gabriele Perna🇮🇹 · Giovanni Salmè🇮🇹 · Sergio Scopetta🇮🇹

    The semi-inclusive correlator for a $\mathcal{J}$=1/2 bound-system, composed by A spin-1/2 fermions, is linearly expressed in terms of the light-front Poincaré covariant spin-dependent spectral function, in valence approximation. The light-front spin-dependent spectral function is fully determined by six scalar functions that allow for a complete description of the six T-even transverse-momentum distributions, suitable for a detailed investigation of the dynamics inside the bound system. The application of the developed formalism to a case with a sophisticated dynamical content, like ${}^3$He, reaches two goals: (i) to illustrate a prototype of an investigation path for gathering a rich wealth of information on the dynamics and also finding valuable constraints to be exploited from the phenomenological standpoint; (ii) to support for the three-nucleon system a dedicated experimental effort for obtaining a detailed 3D picture in momentum space. In particular, the orbital-angular momentum decomposition of the bound state can be studied through the assessment of relations among the transverse-momentum distributions, as well as the relevance of the relativistic effect generated by the implementation of macrocausality. A fresh evaluation of the longitudinal and transverse polarizations of the neutron and proton is also provided, confirming essentially the values used in the standard procedure for extracting the neutron structure functions from both deep-inelastic scattering and semi-inclusive reactions, in the same kinematical regime.

    ↳ nucl-thhep-phPRC(2021)·9 citations
23. 23*

    A method to remove lower order contributions in multi-particle femtoscopic correlation functions

    Raffaele Del Grande🇩🇪 · Laura Šerkšnytė🇩🇪 · Laura Fabbietti🇩🇪 · Valentina Mantovani Sarti🇩🇪 · Dimitar Mihaylov🇩🇪

    In recent years the femtoscopy technique has been used by the ALICE Collaboration in small colliding systems at the LHC to investigate the strong-interaction of hadron pairs in the low-energy regime. The extension of this technique to the study of many-body correlations aims to deliver in the next years the first experimental measurements of the genuine many-hadron interactions, provided that the contributions due to the lower order terms are properly accounted for. In this paper we present a method that allows to determine the residual lower order contributions to the three-body correlation functions, based on the cumulant decomposition approach and on kinematic transformations. A procedure to simulate genuine three-body correlations in three-baryon correlation functions is also developed. A qualitative study of the produced correlation signal is performed by varying the strength of the adopted three-body interaction model and comparisons with the expectations for the lower order contributions to the correlation function are shown. The method can be also applied to evaluate the combinatorial background in the two-body correlation functions, providing an improved statistical accuracy with respect to the standard techniques. The example of the contribution by the pK${}^{+}$K${}^{-}$ channel to the recently measured p$\varphi$ correlation is discussed.

    ↳ nucl-thhep-exhep-phnucl-exEPJC(2022)·23 citations
24. 24*

    Stochastic Properties of Ultralight Scalar Field Gradients

    Mariangela Lisanti🇺🇸 · Matthew Moschella🇺🇸 · William Terrano🇺🇸

    Ultralight axion-like particles are well-motivated dark matter candidates that are the target of numerous direct detection efforts. In the vicinity of the Solar System, such particles can be treated as oscillating scalar fields. The velocity dispersion of the Milky Way determines a coherence time of about 10^6 oscillations, beyond which the amplitude of the axion field fluctuates stochastically. Any analysis of data from an axion direct detection experiment must carefully account for this stochastic behavior to properly interpret the results. This is especially true for experiments sensitive to the gradient of the axion field that are unable to collect data for many coherence times. Indeed, the direction, in addition to the amplitude, of the axion field gradient fluctuates stochastically. We present the first complete stochastic treatment for the gradient of the axion field, including multiple computationally efficient methods for performing likelihood-based data analysis, which can be applied to any axion signal, regardless of coherence time. Additionally, we demonstrate that ignoring the stochastic behavior of the gradient of the axion field can potentially result in failure to discover a true axion signal.

    ↳ astro-ph.COhep-exhep-phphysics.atom-phPRD(2021)·60 citations
25. 25*

    Cosmic-Ray Positrons Strongly Constrain Leptophilic Dark Matter

    Isabelle John🇸🇪 · Tim Linden🇸🇪

    Cosmic-ray positrons have long been considered a powerful probe of dark matter annihilation. In particular, myriad studies of the unexpected rise in the positron fraction have debated its dark matter or pulsar origins. In this paper, we instead examine the potential for extremely precise positron measurements by AMS-02 to probe hard leptophilic dark matter candidates that do not have spectral features similar to the bulk of the observed positron excess. Utilizing a detailed cosmic-ray propagation model that includes a primary positron flux generated by Galactic pulsars in addition to a secondary component constrained by Helium and proton measurements, we produce a robust fit to the local positron flux and spectrum. We find no evidence for a spectral bump correlated with leptophilic dark matter, and set strong constraints on the dark matter annihilation cross-section that fall below the thermal annihilation cross-section for dark matter masses below 60 GeV and 380 GeV for annihilation into ${\tau }^{+}{\tau }^{-}$ and $e^{+}{e}^{-}$, respectively, in our default model.

    ↳ astro-ph.HEastro-ph.GAhep-phJCAP(2021)·42 citations
26. 26*

    The Inflationary Wavefunction from Analyticity and Factorization

    David Meltzer🇺🇸

    We study the analytic properties of tree-level wavefunction coefficients in quasi-de Sitter space. We focus on theories which spontaneously break dS boost symmetries and can produce significant non-Gaussianities. The corresponding inflationary correlators are (approximately) scale invariant, but are not invariant under the full conformal group. We derive cutting rules and dispersion formulas for the late-time wavefunction coefficients by using factorization and analyticity properties of the dS bulk-to-bulk propagator. This gives a unitarity method which is valid at tree-level for general $n$-point functions and for fields of arbitrary mass. Using the cutting rules and dispersion formulas, we are able to compute $n$-point functions by gluing together lower-point functions. As an application, we study general four-point, scalar exchange diagrams in the EFT of inflation. We show that exchange diagrams constructed from boost-breaking interactions can be written as a finite sum over residues. Finally, we explain how the dS identities used in this work are related by analytic continuation to analogous identities in Anti-de Sitter space.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2021)·112 citations
27. 27*

    Proca Q-balls and Q-shells

    Julian Heeck🇺🇸 · Arvind Rajaraman🇺🇸 · Rebecca Riley🇺🇸 · Christopher B. Verhaaren🇺🇸

    Non-topological solitons such as Q-balls and Q-shells have been studied for scalar fields invariant under global and gauged U(1) symmetries. We generalize this framework to include a Proca mass for the gauge boson, which can arise either from spontaneous symmetry breaking or via the Stückelberg mechanism. A heavy (light) gauge boson leads to solitons reminiscent of the global (gauged) case, but for intermediate values these Proca solitons exhibit completely novel features such as disconnected regions of viable parameter space and Q-shells with unbounded radius. We provide numerical solutions and excellent analytic approximations for both Proca Q-balls and Q-shells. These allow us to not only demonstrate the novel features numerically, but also understand and predict their origin analytically.

    ↳ hep-thhep-phJHEP(2021)·22 citations
28. 28*

    Effect of the inner horizon on the black hole thermodynamics: Reissner-Nordström black hole and Kerr black hole

    G.E. Volovik🇫🇮

    For the Schwarzschild black hole the Bekenstein-Hawking entropy is proportional to the area of the event horizon. For the black holes with two horizons the thermodynamics is not very clear, since the role of the inner horizons is not well established. Here we calculate the entropy of the Reissner-Nordström black hole and of the Kerr black hole, which have two horizons. For the spherically symmetric Reissner-Nordström black hole we used several different approaches. All of them give the same result for the entropy and for the corresponding temperature of the thermal Hawking radiation. The entropy is not determined by the area of the outer horizon, and it is not equal to the sum of the entropies of two horizons. It is determined by the correlations between the two horizons, due to which the total entropy of the black hole and the temperature of Hawking radiation depend only on mass $M$ of the black hole and do not depend on the black hole charge $Q$. For the Kerr and Kerr-Newman black holes it is shown that their entropy has the similar property: it depends only on mass $M$ of the black hole and does not depend on the angular momentum $J$ and charge $Q$.

    ↳ gr-qccond-mat.otherhep-phMod.Phys.Lett.A(2021)·25 citations

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