Wed·Jun 30, 2021Wednesday·June 30, 2021

1. 01*

   High-quality axions in solutions to the $\mu$ problem

   Prudhvi N. Bhattiprolu🇺🇸 · Stephen P. Martin🇺🇸

   Solutions to the $\mu$ problem in supersymmetry based on the Kim-Nilles mechanism naturally feature a Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion with decay constant of order the geometric mean of the Planck and TeV scales, consistent with astrophysical limits. We investigate minimal models of this type with two gauge-singlet fields that break a Peccei-Quinn symmetry, and extensions with extra vectorlike quark and lepton supermultiplets consistent with gauge coupling unification. We show that there are many anomaly-free discrete symmetries, depending on the vectorlike matter content, that protect the Peccei-Quinn symmetry to sufficiently high order to solve the strong CP problem. We study the axion couplings in this class of models. Models of this type that are automatically free of the domain wall problem require at least one pair of strongly interacting vectorlike multiplets with mass at the intermediate scale, and predict axion couplings that are greatly enhanced compared to the minimal supersymmetric DFSZ models, putting them within reach of proposed axion searches.

   hep-phPRD(2021)·30 citations
2. 02*

   Magnetic moments and transition magnetic moments of $P_c$ and $P_{cs}$ states

   Ming-Wei Li🇨🇳 · Zhan-Wei Liu🇨🇳 · Zhi-Feng Sun🇨🇳 · Rui Chen🇨🇳

   We study the magnetic moments and transition magnetic moments of $P_c$ and $P_{cs}$ states in the molecular picture. We first revisit the magnetic moments of $P_c$ states as the $S$ wave molecular states without coupled channel effects. The coupled channel effects and the $D$ wave contributions are then investigated carefully. The coupled channel effects contribute to the change of $0.1\sim 0.4$ nuclear magneton ${\mu }_N$ for most cases while the $D$ wave only induces the variation of less than $0.03{\mu }_N$. In addition, we obtain the transition magnetic moments between different $P_c$ states and the related electromagnetic decay widths of $P_c^{\prime }\to P_c\gamma$. The magnetic moments of $P_{cs}$ are much different for the assumption of spin being 1/2 and 3/2. The study of electromagnetic properties will help us disclose further the structure of these unconventional states.

   hep-phPRD(2021)·57 citations
3. 03*

   GTMD model predictions for diffractive dijet production at EIC

   Daniël Boer🇳🇱 · Chalis Setyadi🇳🇱

   In this paper we consider a small-$x$ model for gluon GTMDs that we fit to data on diffractive dijet production in electron-proton collisions obtained by HERA's H1 Collaboration. Assuming a small number of free parameters, each with a physical motivation, we are able to describe those data fairly well and with this model we obtain predictions for the EIC for both electroproduction and photoproduction which may allow to further test the underlying GTMD description. In the general discussion of the impact parameter dependence we recall some subtle issues related to localization of states, choice of frames, and discuss what these aspects imply for the range of applicability of the model.

   hep-phhep-exPRD(2021)·45 citations
4. 04*

   Line shape and the experimental determination of the $J/\psi \to \gamma {\eta }_c$ branching fraction

   Jorge Segovia🇪🇸 · Jaume Tarrús Castellà🇪🇸

   We study the photon spectrum line-shape of the $J/\psi \to \gamma {\eta }_c\to \gamma X$ decay process in a nonrelativistic effective field theory (EFT) framework of quantum chromodynamics (QCD). We take into account the finite width of the ${\eta }_c$ and include $\mathcal{O}(v^2)$ corrections. We observe that the photon spectrum line-shape is divergent at large energies due to polynomially and logarithmically divergent terms, that upon integration over the photon energies in Dimensional Regularization (DR) produce no contribution or can be renormalized. We propose to subtract these divergences at the line-shape level in a manner consistent with the calculation of the width in DR and $\overline{MS}$ scheme. We analyze CLEO's data with the proposed subtracted line-shape and find good agreement between the theoretical prediction and the experimental result.

   hep-phhep-exPRD(2021)·6 citations
5. 05*

   Axion Quality Straight from the GUT

   Luca Vecchi🇮🇹

   Composite axion scenarios offer a robust field theoretic justification for the existence of a Peccei-Quinn symmetry of high quality. We present a new class of realizations that are naturally embedded in Grand-Unified Theories, retain asymptotic freedom for all gauge groups, and protect the axion symmetry up to operators of dimension 12. Our setup leads to a number of distinctive signatures at low energies. First, additional composite scalars are predicted; some of these are viable dark matter candidates for values of the axion decay constant that are too low for the QCD axion abundance to be relevant. Second, an approximate unification of the Standard Model gauge couplings takes place at the axion scale, while leaving the actual quark-lepton unification at much higher energies as usual. This suggests the existence of GUT relics with Standard Model gauge quantum numbers at potentially accessible scales.

   hep-phEPJC(2021)·25 citations
6. 06*

   Imprint of SUSY in radiative B-meson decays

   H. Eberl (1)🇦🇹 · K. Hidaka (2)🇯🇵 · E. Ginina (1, 3)🇦🇹 · A. Ishikawa (4, 5,6) ((1) HEPHY, Vienna, (2) Tokyo Gakugei U., (3) VRV, Vienna, (4) KEK, Tsukuba, (5) SOKENDAI, Hayama, (6) ICEPP, Tokyo)🇯🇵

   We study supersymmetric (SUSY) effects on $C_7({\mu }_b)$ and $C_7^{\prime }({\mu }_b)$ which are the Wilson coefficients (WCs) for $b\to s\gamma$ at b-quark mass scale ${\mu }_b$ and are closely related to radiative $B$-meson decays. The SUSY-loop contributions to $C_7({\mu }_b)$ and $C_7^{\prime }({\mu }_b)$ are calculated at leading order (LO) in the Minimal Supersymmetric Standard Model (MSSM) with general quark-flavour violation (QFV). For the first time we perform a systematic MSSM parameter scan for the WCs $C_7({\mu }_b)$ and $C_7^{\prime }({\mu }_b)$ respecting all the relevant constraints, i.e. the theoretical constraints from vacuum stability conditions and the experimental constraints, such as those from $K$- and $B$-meson data and electroweak precision data, as well as recent limits on SUSY particle masses and the 125 GeV Higgs boson data from LHC experiments. From the parameter scan we find the following: (1) The MSSM contribution to Re($C_7({\mu }_b)$) can be as large as $\sim \pm 0.05$, which could correspond to about 3$\sigma$ significance of New Physics (NP) signal in the future LHCb and Belle II experiments. (2) The MSSM contribution to Re($C_7^{\prime }({\mu }_b)$) can be as large as $\sim -0.08$, which could correspond to about 4$\sigma$ significance of NP signal in the future LHCb and Belle II experiments. (3) These large MSSM contributions to the WCs are mainly due to (i) large scharm-stop mixing and large scharm/stop involved trilinear couplings, (ii) large sstrange-sbottom mixing and large sstrange-sbottom involved trilinear couplings and (iii) large bottom Yukawa coupling $Y_b$ for large $\tan \beta$ and large top Yukawa coupling $Y_t$. In case such large NP contributions to the WCs are really observed in the future experiments at Belle II and LHCb Upgrade, this could be the imprint of QFV SUSY (the MSSM with general QFV).

   hep-phPRD(2021)·14 citations
7. 07*

   Phenomenological study of quarkonium suppression and the impact of the energy gap between singlets and octets

   Jean-Paul Blaizot🇫🇷 · Miguel Ángel Escobedo🇪🇸

   The study of heavy quarkonium suppression in heavy-ion collisions represents an important source of information about the properties of the quark-gluon plasma produced in such collisions. In a previous paper, we have considered how to model the evolution of a quarkonium in such a way that the solution of the resulting equations evolves toward the correct thermal equilibrium distribution for an homogeneous and static medium. We found that it is crucial to take into account the energy gap between singlet and octet configurations when the temperature is not much greater than this energy gap. In this manuscript, we explore in more detail the phenomenological consequences of this observation in the more realistic situation of an expanding system. We consider two different scenarios, based on the same approximation scheme, but on different choices of parameters. In the first case, we rely on a Hard Thermal Loop approximation, while the second case is based on a recent determination of the static potential in lattice QCD. In both cases, we compute the decay width and the nuclear modification factor, both taking the energy gap into account and ignoring it. We find that the impact on the predictions is as large in the expanding medium as it is in the static case. Our conclusion is that this energy gap should be taken into account in phenomenological studies.

   hep-phnucl-thPRD(2021)·27 citations
8. 08*

   Confirmation of the existence of an exotic state in the $\pi D$ system

   Eric B. Gregory🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Stefan Krieg🇩🇪 · Thomas Luu🇩🇪

   In recent years many candidates for states beyond the most simple realization of the quark model were found in various experiments around the world. However, so far no consensus exists on their structure, although there is strong evidence that at least some of those are dynamically generated from meson-meson interactions. In this Letter we provide an important missing piece from the theoretical side to prove that the lightest open charm strange and non-strange scalars $D_{s0}^{\ast }(2317)$ and $D_0^{\ast }$ as well as their axial-vector partner states can all be understood as emerging from the interactions between Goldstone bosons stemming from the spontaneous breaking of chiral symmetry and the ground state charmed mesons. For that purpose we exploit the flavor multiplet structure of the lightest open-charm positive-parity scalar states in an SU(3) symmetric lattice QCD simulation at large pion masses to establish that there exists a bound state in the flavor-sextet representation, which cannot emerge for quark-antiquark states but appears naturally for four-quark configurations. Moreover, we find repulsion in the $[15]$ representation and thus no single-particle state in this representation exists, falsifying the expectation for tetraquark models. The findings establish the pattern predicted for the interactions of Goldstone bosons with $D$ mesons from chiral symmetry and the paradigm of the lowest-lying positive-parity charmed mesons as dynamically generated states.

   hep-phhep-lat20 citations
9. 09*

   $P$-wave charmed baryons of the $SU(3)$ flavor $6_F$

   Hui-Min Yang🇨🇳 · Hua-Xing Chen🇨🇳

   We use QCD sum rules to study mass spectra of $P$-wave charmed baryons of the $SU(3)$ flavor $6_F$. We also use light-cone sum rules to study their $S$- and $D$-wave decays into ground-state charmed baryons together with light pseudoscalar and vector mesons. We work within the framework of heavy quark effective theory, and we also consider the mixing effect. Our results can explain many excited charmed baryons as a whole, including the ${\Sigma }_c(2800{)}^0$, ${\Xi }_c(2923{)}^0$, ${\Xi }_c(2939{)}^0$, ${\Xi }_c(2965{)}^0$, ${\Omega }_c(3000{)}^0$, ${\Omega }_c(3050{)}^0$, ${\Omega }_c(3066{)}^0$, ${\Omega }_c(3090{)}^0$, and ${\Omega }_c(3119{)}^0$. Their masses, mass splittings within the same multiplets, and decay properties are extracted for future experimental searches.

   hep-phhep-exPRD(2021)·42 citations
10. 10*

    $P$-wave quarkonium wavefunctions at the origin in the $\overline{\mathrm{MS}}$ scheme

    Hee Sok Chung🇩🇪

    We compute $P$-wave quarkonium wavefunctions at the origin in the $\overline{\mathrm{MS}}$ scheme based on nonrelativistic effective field theories. We include nonperturbative effects from the long-distance behaviors of the potential, while the short-distance behaviors are determined from perturbative QCD. We obtain $\overline{\mathrm{MS}}$-renormalized $P$-wave quarkonium wavefunctions at the origin that have the correct scale dependences that are expected from factorization formalisms, so that the dependences on the scheme and scale cancel in physical quantities. This greatly reduces the theoretical uncertainties associated with scheme and scale dependences in predictions of decay and production rates. Based on the calculation of the $P$-wave wavefunctions at the origin in this work, we make first-principles predictions of electromagnetic decay rates and exclusive electromagnetic production rates of $P$-wave charmonia and bottomonia, and compare them with measurements.

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

    Cross-link relations between $\pi$ and $\rho$-meson channels and the QCD vacuum

    S. V. Mikhailov🇷🇺 · N. G. Stefanis🇩🇪

    We discuss cross-link relations between the $\pi$ and $\rho$-meson channels emerging from two different descriptions of the QCD vacuum: Instanton physics and QCD sum rules with nonlocal condensates (NLC). We derive in both schemes an intriguing linear relation between the $\pi$ and the ${\rho }^{\Vert }$-meson distribution amplitudes in terms of their conformal coefficients and work out the specific impact of the scalar NLC in these two channels. Using a simple model with Gaussian decay of the scalar NLC, we are able to relate it to the moments of the pion non-singlet parton distribution function measurable in experiment -- a highly nontrivial result. The implications for the pion and the ${\rho }^{\Vert }$-meson DAs entailed by the obtained cross-link relations are outlined in terms of two generic scenarios.

    hep-phhep-thPRD(2021)·2 citations
12. 12*

    Baryogenesis via relativistic bubble expansion

    Iason Baldes🇧🇪 · Simone Blasi🇧🇪 · Alberto Mariotti🇧🇪 · Alexander Sevrin🇧🇪 · Kevin Turbang🇧🇪

    We present a novel baryogenesis mechanism in which the asymmetry is sourced from heavy particles which either gain their mass or are created during bubble expansion in a strong first order phase transition. These particles then decay in a CP and baryon number violating way inside the bubble. The particles are inherently out-of-equilibrium and sufficiently dilute after wall crossing so the third Sakharov condition is easily met. Washout is avoided provided the reheat temperature is sufficiently below the scale of the heavy particles. The mechanism relies on moderate supercooling and relativistic walls which -- in contrast to electroweak baryogenesis -- generically leads to a sizable gravitational wave signal, although in the simplest realisations at frequencies beyond upcoming detectors. We present a simple example model and discuss the restrictions on the parameter space for the mechanism to be successful. We find that high reheat temperatures $T_{\mathrm{RH}}\gtrsim 10^{10}$ GeV are generally preferred, whereas stronger supercooling allows for temperatures as low as $T_{\mathrm{RH}}\sim 10^6$ GeV, provided the vacuum energy density is sufficiently suppressed. We briefly comment on using resonantly enhanced CP violation to achieve even lower scales.

    hep-phPRD(2021)·109 citations
13. 13*

    Symmetry breaking induced by pairwise conversion of neutrinos in compact sources

    Shashank Shalgar🇩🇰 · Irene Tamborra🇩🇰

    A surprising consequence of non-linear flavor evolution is the spontaneous breaking of the initial symmetries of the neutrino gas propagating in a dense astrophysical environment. We explore the flavor conversion physics by taking into account the polar and azimuthal angular distributions of neutrinos and present the very first example of spontaneous symmetry breaking in the context of fast flavor mixing in the nonlinear regime. Intriguingly, we find that fast flavor mixing does not always develop in the proximity of the angular regions with vanishing electron lepton number, as commonly assumed, and large flavor mixing can rapidly spread through all neutrino modes. Such behavior cannot be predicted from the linear regime of the flavor evolution. These results can have major consequences on the physics of compact astrophysical objects.

    hep-phastro-ph.HEPRD(2022)·19 citations
14. 14*

    Spin asymmetries in electron-jet production at the future electron ion collider

    Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Ding Yu Shao🇨🇳 · Fanyi Zhao🇺🇸

    We study all the possible spin asymmetries that can arise in back-to-back electron-jet production, $ep\to e+\text{jet}+X$, as well as the associated jet fragmentation process, $ep\to e+\text{jet}(h)+X$, in electron-proton collisions. We derive the factorization formalism for these spin asymmetries and perform the corresponding phenomenology for the kinematics relevant to the future electron ion collider. In the case of unpolarized electron-proton scattering, we also give predictions for azimuthal asymmetries for the HERA experiment. This demonstrates that electron-jet production is an outstanding process for probing unpolarized and polarized transverse momentum dependent parton distribution functions and fragmentation functions.

    hep-phhep-exnucl-exnucl-thJHEP(2021)·46 citations
15. 15*

    Muon g-2 from Millicharged Hidden Confining Sector

    Yang Bai🇺🇸 · Seung J. Lee🇰🇷 · Minho Son🇰🇷 · Fang Ye🇰🇷

    We provide a novel explanation to the muon $g-2$ excess with new physics contributions at the two-loop level. In this scenario, light millicharged particles are introduced to modify the photon vacuum polarization that contributes to muon $g-2$ at one additional loop. The muon $g-2$ excess can be explained with the millicharged particle mass $m_{\chi }$ around 10 MeV and the product of the multiplicity factor and millicharge squared of $N_{\chi }{\epsilon }^2\sim 10^{-3}$. The minimal model faces severe constraints from direct searches at fixed-target experiments and astrophysical observables. However, if the millicharged particles are also charged under a hidden confining gauge group $SU(N_{\chi })$ with a confinement scale of MeV, hidden-sector hadrons are unstable and can decay into neutrinos, which makes this scenario consistent with existing constraints. This explanation can be well tested at low-energy lepton colliders such as BESIII and Belle II as well as other proposed fixed-target experiments.

    hep-phhep-exJHEP(2021)·14 citations
16. 16*

    From B-meson anomalies to Kaon physics with scalar leptoquarks

    David Marzocca🇮🇹 · Sokratis Trifinopoulos🇮🇹 · Elena Venturini🇩🇪

    In this work we study possible connections between $B$-meson anomalies and Kaon physics observables in the context of combined solutions with the singlet and triplet scalar leptoquarks $S_1$ and $S_3$. By assuming a flavor structure for the leptoquark couplings dictated by a minimally broken $U(2{)}^5$ flavor symmetry we can make a sharp connection between these two classes of observables. We find that the bound on $\mathcal{B}(K^{+}\to {\pi }^{+}\nu \nu )$ from NA62 puts already some tension in the model, while the present limits on $\mathcal{B}(K_L\to {\mu }^{+}{\mu }^{-})$ and $\mu \to e$ conversion in nuclei can be saturated. Relaxing instead the flavor assumption we study what values for $\mathcal{B}(K^{+}\to {\pi }^{+}\nu \nu )$, as well as for $\mathcal{B}(K_L\to {\pi }^0\nu \nu )$ and $\mathcal{B}(K_{L,S}\to {\mu }^{+}{\mu }^{-})$, are viable compatibly with all other phenomenological constraints.

    hep-phEPJC(2022)·47 citations
17. 17*

    Complete analysis of all $B\to \pi K$ decays

    Anirban Kundu🇮🇳 · Sunando Kumar Patra🇮🇳 · Shibasis Roy🇮🇳

    The Standard Model (SM) predicts that $\Delta A_{\mathrm{CP}}$, the difference between the direct CP asymmetries for the modes $B^{+}\to {\pi }^0{K}^{+}$ and $B^0\to {\pi }^{-}{K}^{+}$ that are related by weak isospin, should be close to zero. There has been a recent claim by the LHCb Collaboration that the measured value of $\Delta A_{\mathrm{CP}}$ shows an uncomfortable tension with the SM prediction, almost at the $8\sigma$ level. Motivated by this claim, we critically re-examine the data on all the $B\to \pi K$ modes, including the CP asymmetries and CP-averaged branching fractions. From a combined Bayesian analysis with the topological amplitudes and their phases as the free parameters, we find that the best-fit region has a large overlap with the parameter space favoured in the SM, albeit with some enhancement for the electroweak penguin and the colour-suppressed tree amplitudes, consistent with the findings of earlier studies. We find that in this SM-like region, $\Delta A_{\mathrm{CP}}$ is more than 5$\sigma$ away from zero and the tension with the global average, as well as the LHCb result, is within $2\sigma$. Thus we conclude that there is not yet enough motivation to go beyond the SM.

    hep-phhep-exPRD(2021)·6 citations
18. 18*

    Confronting SO(10) GUTs with proton decay and gravitational waves

    Stephen F. King🇬🇧 · Silvia Pascoli🇬🇧 · Jessica Turner🇬🇧 · Ye-Ling Zhou🇨🇳

    Grand Unified Theories (GUT) predict proton decay as well as the formation of cosmic strings which can generate gravitational waves. We determine which non-supersymmetric $SO(10)$ breaking chains provide gauge unification in addition to a gravitational signal from cosmic string decay. We calculate the GUT and intermediate scales for these $SO(10)$ breaking chains by solving the renormalisation group equations at the two-loop level. This analysis predicts the GUT scale, hence the proton lifetime, in addition to the scale of cosmic string generation and thus the associated gravitational wave signal. We determine which $SO(10)$ breaking chains survive in the event of the null results of the next generation of gravitational waves and proton decay searches and determine the correlations between proton decay and gravitational waves scales if these observables are measured.

    hep-phJHEP(2021)·67 citations
19. 19*

    Large-scale gauge spectra and pseudoscalar couplings

    Massimo Giovannini🇨🇭

    It is shown that the slopes of the superhorizon hypermagnetic spectra produced by the variation of the gauge couplings are practically unaffected by the relative strength of the parity-breaking terms. A new method is proposed for the estimate of the gauge power spectra in the presence of pseudoscalar interactions during inflation. To corroborate the general results, various concrete examples are explicitly analyzed. Since the large-scale gauge spectra also determine the late-time magnetic fields it turns out that the pseudoscalar contributions have little impact on the magnetogenesis requirement. Conversely the parity-breaking terms crucially affect the gyrotropic spectra that may seed, in certain models, the baryon asymmetry of the Universe. In the most interesting regions of the parameter space the modes reentering prior to symmetry breaking lead to a sufficiently large baryon asymmetry while the magnetic power spectra associated with the modes reentering after symmetry breaking may even be of the order of a few hundredths of a nG over typical length scales comparable with the Mpc prior to the collapse of the protogalaxy. From the viewpoint of the effective field theory description of magnetogenesis scenarios these considerations hold generically for the whole class of inflationary models where the inflaton is not constrained by any underlying symmetry.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2021)·14 citations
20. 20*

    Jointly modelling Cosmic Inflation and Dark Energy

    Konstantinos Dimopoulos🇬🇧

    Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy. The requirements for modelling quintessential inflation are described and two explicit successful models are presented in the context of $\alpha$-attractors and Palatini modified gravity.

    ↳ gr-qcastro-ph.COhep-phhep-thJ.Phys.Conf.Ser.(2021)·11 citations
21. 21*

    Solving the puzzle of nuclear stopping power

    Marek Jeżabek🇵🇱 · Andrzej Rybicki🇵🇱

    This paper reviews our recent findings on the dynamics of transport of baryon number in proton-induced reactions at the CERN SPS. These are put in a more general context of the present understanding of baryon stopping phenomena up to LHC and cosmic ray energies. The implications of our studies, advantages to be provided by modern and high quality experimental data, and perspectives of new measurements are shortly discussed.

    ↳ nucl-thhep-phActa Phys.Polon.B(2021)·4 citations
22. 22*

    The Axial Anomaly in Lorentz Violating Theories: Towards the Electromagnetic Response of Weakly Tilted Weyl Semimetals

    Andrés Gómez🇲🇽 · Luis Urrutia🇲🇽

    Using the path integral formulation in Euclidean space, we extended the calculation of the abelian chiral anomalies in the case of Lorentz violating theories by considering a new fermionic correction term provided by the standard model extension, which arises in the continuous Hamiltonian of a weakly tilted Weyl semimetal, and whose cones have opposite tilting. We found that this anomaly is insensitive to the tilting parameter, retaining its well-known covariant form. This independence on the Lorentz violating parameters is consistent with other findings reported in the literature. The initially imposed gauge invariant regularization was consistently recovered at the end of the calculation by the appearance of highly non-trivial combinations of the covariant derivatives, which ultimately managed to give only terms containing the electromagnetic tensor. We emphasize that the value of the anomaly with an arbitrary parameter is not automatically related to the effective action describing the electromagnetic response of such materials

    ↳ cond-mat.mes-hallhep-phhep-thSymmetry(2021)·6 citations
23. 23*

    Multi-interacting dark energy and its cosmological implications

    Matteo Lucca🇧🇪

    In the effort to define the main features a successful solution to the Hubble tension should have, growing evidence has emerged pointing to the need for models able to modify the expansion (and possibly thermal) history of the universe both prior and after recombination, and that could thereby restore the overall concordance between early- and late-time observations without introducing nor worsening other cosmological tensions in the process. In precisely this spirit, here we consider a multi-interacting dark energy model with two complementary interaction channels: one with the dark matter and one with the photons. The former most significantly affects the matter dominated epoch as well as the very late universe, and has been shown to be able to significantly resolve the $S_8$ tension. The latter has been introduced in this work to allow for a larger and natural time dependence of the evolution of the universe since it mostly impacts the radiation dominated epoch as well as the temperature scaling of the photons, as extensively explained in the text. As a result, considering data from Planck+BAO+Pantheon+KV450+DES (which can be combined since the $S_8$ value is lowered even neglecting the weak lensing data) we find that the significance of the $H_0$ tension only reduces to about 3.5$\sigma$, while that of the $S_8$ tension falls below the 2$\sigma$ level. Also, the statistical analysis we perform strongly favors $\Lambda$CDM in all considered cases. Overall, we conclude that the specific multi-interacting dark energy model considered here, despite its broad generality and very rich cosmological phenomenology, cannot successfully restore the aforementioned overall concordance between early- and late-time observations.

    ↳ astro-ph.COhep-phPRD(2021)·50 citations
24. 24*

    On the most constraining cosmological neutrino mass bounds

    Eleonora Di Valentino🇬🇧 · Stefano Gariazzo🇮🇹 · Olga Mena🇪🇸

    We present here up-to-date neutrino mass limits exploiting the most recent cosmological data sets. By making use of the Cosmic Microwave Background temperature fluctuation and polarization measurements, Supernovae Ia luminosity distances, Baryon Acoustic Oscillation observations and determinations of the growth rate parameter, we are able to set the most constraining bound to date, $\sum m_{\nu }<0.09$ eV at $95\%$~CL. This very tight limit is obtained without the assumption of any prior on the value of the Hubble constant and highly compromises the viability of the inverted mass ordering as the underlying neutrino mass pattern in nature. The results obtained here further strengthen the case for very large multitracer spectroscopic surveys as unique laboratories for cosmological relics, such as neutrinos: that would be the case of the Dark Energy Spectroscopic Instrument (DESI) survey and of the Euclid mission.

    ↳ astro-ph.COhep-phPRD(2021)·146 citations
25. 25*

    Vacuum correlators at short distances from lattice QCD

    Marco Cè🇨🇭 · Tim Harris🇬🇧 · Harvey B. Meyer🇩🇪 · Arianna Toniato🇩🇪 · Csaba Török🇩🇪

    Non-perturbatively computing the hadronic vacuum polarization at large photon virtualities and making contact with perturbation theory enables a precision determination of the electromagnetic coupling at the $Z$ pole, which enters global electroweak fits. In order to achieve this goal ab initio using lattice QCD, one faces the challenge that, at the short distances which dominate the observable, discretization errors are hard to control. Here we address challenges of this type with the help of static screening correlators in the high-temperature phase of QCD, yet without incurring any bias. The idea is motivated by the observations that (a) the cost of high-temperature simulations is typically much lower than their vacuum counterpart, and (b) at distances $x_3$ far below the inverse temperature $1/T$, the operator-product expansion guarantees the thermal correlator of two local currents to deviate from the vacuum correlator by a relative amount that is power-suppressed in $(x_{3}T)$. The method is first investigated in lattice perturbation theory, where we point out the appearance of an O$(a^2\log (1/a))$ lattice artifact in the vacuum polarization with a prefactor that we calculate. It is then applied to non-perturbative lattice QCD data with two dynamical flavors of quarks. Our lattice spacings range down to 0.049 fm for the vacuum simulations and down to 0.033 fm for the simulations performed at a temperature of 250 MeV.

    ↳ hep-lathep-phJHEP(2021)·29 citations
26. 26*

    A special Higgs challenge: Measuring the mass and production cross section with ultimate precision at FCC-ee

    Paolo Azzurri🇮🇹 · Gregorio Bernardi🇫🇷 · Sylvie Braibant🇮🇹 · David d'Enterria🇨🇭 · Jan Eysermans🇺🇸 · Patrick Janot🇨🇭 · Ang Li🇫🇷 · Emmanuel Perez🇨🇭

    The FCC-ee offers powerful opportunities to determine the Higgs boson parameters, exploiting over $10^6$ ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to \mathrm{ZH}$ events and almost $10^5$ $\mathrm{WW}\to \mathrm{H}$ events at centre-of-mass energies around 240 and 365 GeV. This essay spotlights the important measurements of the ZH production cross section and of the Higgs boson mass. The measurement of the total ZH cross section is an essential input to the absolute determination of the HZZ coupling -- a "standard candle" that can be used by all other measurements, including those made at hadron colliders -- at the per-mil level. A combination of the measured cross sections at the two different centre-of-mass energies further provides the first evidence for the trilinear Higgs self-coupling, and possibly its first observation if the cross-section measurement can be made accurate enough. The determination of the Higgs boson mass with a precision significantly better than the Higgs boson width (4.1 MeV in the Standard Model) is a prerequisite to either constrain or measure the electron Yukawa coupling via direct ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to \mathrm{H}$ production at $\sqrt{s}=125$ GeV. Approaching the statistical limit of 0.1% and $\mathcal{O}(1)$ MeV on the ZH cross section and the Higgs boson mass, respectively, sets highly demanding requirements on accelerator operation (ZH threshold scan, centre-of-mass energy measurement), detector design (lepton momentum resolution, hadronic final state reconstruction performance), theoretical calculations, and analysis techniques (efficiency and purity optimization with modern tools, constrained kinematic fits, control of systematic uncertainties). These challenges are examined in turn in this essay.

    ↳ hep-exhep-phEur.Phys.J.Plus(2022)·37 citations
27. 27*

    Hunt for rare processes and long-lived particles at FCC-ee

    Marcin Chrzaszcz🇵🇱 · Rebeca Gonzalez Suarez🇸🇪 · Stéphane Monteil🇫🇷

    In this essay we discuss the possibilities and associated challenges concerning beyond the Standard Model searches at FCC-ee, such as rare decays of heavy-flavoured particles and long-lived particles. The Standard Model contains several suppression mechanisms, which cause a given group of processes to happen rarely, resulting in rare decays. The interest in these decays lies in the fact that the physics beyond the Standard Model does not need to be affected by the same suppression mechanism and therefore can naturally manifest in these decays. Their interest is reinforced by the recent report of several measurements of $b$-flavoured rare decays, showing deviations with respect to the Standard Model predictions. We will show how the FCC-ee project has unique capabilities to address these scientific questions and will consider the related detector design challenges to meet. Another group of processes discussed are those that produce new particles with relatively long lifetimes, that travel substantial distances inside the detectors before decaying. Models containing long-lived particles can give answers to many open questions of the Standard Model, such as the nature of dark matter, or the neutrino masses, among others; while providing an interesting experimental complement to mainstream searches. Long-lived particles often display unique experimental signatures, such as displaced tracks and vertices, disappearing tracks, or anomalously charged jets. Due to this, they are affected by very low background levels but in exchange, they often require dedicated reconstruction algorithms and triggers.

    ↳ hep-exhep-phEur.Phys.J.Plus(2021)·19 citations
28. 28*

    Exactly Solvable Vacuum Decays with Gravity

    J.R. Espinosa🇪🇸 · J.-F. Fortin🇨🇦 · J. Huertas🇪🇸

    Using a new approach to the analysis of false vacuum decay based on the so-called tunneling potential, we develop a general method to find scalar potentials with a false vacuum with exactly solvable decay at the semi-classical level, including gravitational corrections. We examine in particular the decays of de Sitter vacua providing concrete examples that allow to explore analytically the transition between the Coleman-De Luccia and Hawking-Moss regimes.

    ↳ hep-thgr-qchep-phPRD(2021)·16 citations
29. 29*

    Fast & accurate emulation of two-body scattering observables without wave functions

    J. A. Melendez🇺🇸 · C. Drischler🇺🇸 · A. J. Garcia🇺🇸 · R. J. Furnstahl🇺🇸 · Xilin Zhang🇺🇸

    We combine Newton's variational method with ideas from eigenvector continuation to construct a fast & accurate emulator for two-body scattering observables. The emulator will facilitate the application of rigorous statistical methods for interactions that depend smoothly on a set of free parameters. Our approach begins with a trial $K$ or $T$ matrix constructed from a small number of exact solutions to the Lippmann--Schwinger equation. Subsequent emulation only requires operations on small matrices. We provide several applications to short-range potentials with and without the Coulomb interaction and partial-wave coupling. It is shown that the emulator can accurately extrapolate far from the support of the training data. When used to emulate the neutron-proton cross section with a modern chiral interaction as a function of 26 free parameters, it reproduces the exact calculation with negligible error and provides an over 300x improvement in CPU time.

    ↳ nucl-thcond-mat.mtrl-scihep-lathep-ph+1PLB(2021)·54 citations
30. 30*

    Fibration, Nexus and Cosmological Composite Topological Defects in Uniaxially Disordered Superfluid ${}^3$He

    Kuang Zhang🇫🇮

    The composited cosmological defects in superfluids of nafen-disorded 3He are discussed in this review article. In spite of the existence of the half quantum vortices (Alice strings), more novel composited cosmological defects such as Nambu monople, Kibble-Lazarides-Shafi (KLS) string wall, and nexus objects appear in this system in the two-step successive symmetry breaking phase transition. To reveal them, we analyzed symmetry breaking patterns in detail by using the algebraic topology and group theory. It turns out that the fibrations of the degenerate parameter spaces of symmetry breaking patterns dominate the existence of composite cosmological defects in the successive symmetry breaking of nafen-distorted 3He. To compare our model with ROTA's experiment of string wall, we demonstrate how the KLS string wall extend to 1D nexus in equilibrium states. The equilibrium free energies, which determines the configurations 1D nexus, are evaluated by non-linear numerical optimization algorithm. Based on these equilibrium configurations, we calculated the spectrum of spin dynamical response of system under weak magnetic driving. The results exactly coincide with the experimental observations.

    ↳ cond-mat.othercond-mat.supr-conhep-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.