Fri·Apr 2, 2021Friday·April 2, 2021

1. 01*

   Seesaw determination of the dark matter relic density

   Rupert Coy🇧🇪 · Aritra Gupta🇧🇪 · Thomas Hambye🇧🇪

   In this article, we show that in the usual type-I seesaw framework, augmented solely by a neutrino portal interaction, the dark matter (DM) relic density can be created through freeze-in in a manner fully determined by the seesaw interactions and the DM particle mass. This simple freeze-in scenario, where dark matter is not a seesaw state, proceeds through slow, seesaw-induced decays of Higgs, $W$ and $Z$ bosons. We identify two scenarios, one of which predicts the existence of an observable neutrino line.

   hep-phPRD(2021)·26 citations
2. 02*

   Extended scalar sectors at future colliders

   Tania Robens🇭🇷 · Jan Kalinowski🇵🇱 · Aleksander Filip Zarnecki🇵🇱 · Andreas Papaefstathiou🇺🇸

   After the discovery of the Higgs boson in 2012, particle physics has entered an exciting era. An important question is whether the Standard Model of particle physics correctly describes the scalar sector realized by nature, or whether it is part of a more extended model, featuring additional particle content. A prime way to test this is to probe models with extended scalar sectors at future collider facilities. We here discuss such models in the context of high-luminosity LHC, a possible proton-proton collider with 27 and 100 TeV center-of-mass energy, as well as future lepton colliders with various center-of-mass energies.

   hep-phActa Phys.Polon.B(2021)·7 citations
3. 03*

   Sterile neutrinos with non-standard interactions in $\beta$- and $0\nu \beta \beta$-decay experiments

   Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Tom Tong🇺🇸

   Charged currents are probed in low-energy precision $\beta$-decay experiments and at high-energy colliders, both of which aim to measure or constrain signals of beyond-the-Standard-Model physics. In light of future $\beta$-decay and LHC measurements that will further explore these non-standard interactions, we investigate what neutrinoless double-$\beta$ decay ($0\nu \beta \beta$) experiments can tell us if a nonzero signal were to be found. Using a recently developed effective-field-theory framework, we consider the effects that interactions with right-handed neutrinos have on $0\nu \beta \beta$ and discuss the range of neutrino masses that current and future $0\nu \beta \beta$ measurements can probe, assuming neutrinos are Majorana particles. For non-standard interactions at the level suggested by recently observed hints in $\beta$ decays, we show that next-generation $0\nu \beta \beta$ experiments can determine the Dirac or Majorana nature of neutrinos, for sterile neutrino masses larger than $\mathcal{O}(10)$ eV.

   hep-phJHEP(2021)·20 citations
4. 04*

   LHC signals of the next-to-lightest scalar Higgs state of the NMSSM in the $4\tau$ decay channel

   M. M. Almarashi🇸🇦

   We study the $a_1{a}_1$ and $Z{a}_1$ decay channels of the next-to-lightest CP-even Higgs boson $h_2$ of the NMSSM at the LHC, where the $h_2$ is produced in gluon fusion. It is found that while the $h_2$ discovery is impossible through the latter channel, the former one in the $4\tau$ final state is a promising channel to discover the $h_2$ with masses up to around 250 GeV at the LHC. Such a discovery of the $h_2$ is mostly accompanied with a light $a_1$, which is a clear evidence for distinguishing the NMSSM from the MSSM since such a light $a_1$ is impossible in the MSSM.

   hep-phAdv.High Energy Phys.(2021)·3 citations
5. 05*

   The $D_s$-meson leading-twist distribution amplitude within the QCD sum rules and its application to the $B_s\to D_s$ transition form factor

   Yi Zhang🇨🇳 · Tao Zhong🇨🇳 · Hai-Bing Fu🇨🇳 · Wei Cheng🇨🇳 · Xing-Gang Wu🇨🇳

   We make a detailed study on the $D_s$ meson leading-twist LCDA ${\varphi }_{2;D_s}$ by using the QCD sum rules within the framework of the background field theory. To improve the precision, its moments $⟨{\xi }^n{⟩}_{2;D_s}$ are calculated up to dimension-six condensates. At the scale $\mu =2\mathrm{GeV}$, we obtain: $⟨{\xi }^1{⟩}_{2;D_s}=-0.261_{-0.020}^{+0.020}$, $⟨{\xi }^2{⟩}_{2;D_s}=0.184_{-0.012}^{+0.012}$, $⟨{\xi }^3{⟩}_{2;D_s}=-0.111_{-0.012}^{+0.007}$ and $⟨{\xi }^4{⟩}_{2;D_s}=0.075_{-0.005}^{+0.005}$. Using those moments, the ${\varphi }_{2;D_s}$ is then constructed by using the light-cone harmonic oscillator model. As an application, we calculate the transition form factor $f_{+}^{B_s\to D_s}(q^2)$ within the light-cone sum rules (LCSR) approach by using a right-handed chiral current, in which the terms involving ${\varphi }_{2;D_s}$ dominates the LCSR. It is noted that the extrapolated $f_{+}^{B_s\to D_s}(q^2)$ agrees with the Lattice QCD prediction. After extrapolating the transition form factor to the physically allowable $q^2$-region, we calculate the branching ratio and the CKM matrix element, which give $\mathcal{B}({\bar{B}}_s^0\to D_s^{+}\ell {\nu }_{\ell })=(2.03_{-0.49}^{+0.35})\times 10^{-2}$ and $|V_{cb}|=(40.00_{-4.08}^{+4.93})\times 10^{-3}$.

   hep-phPRD(2021)·19 citations
6. 06*

   Neutral and charged mesons in magnetic fields: A resonance gas in a non-relativistic quark model

   Toru Kojo🇨🇳

   We analyze mesons in constant magnetic fields ($B$) within a non-relativistic constituent quark model. Our quark model contains a harmonic oscillator type confining potential, and we perturbatively treat short range correlations to account for the spin-flavor energy splittings. We study both neutral and charged mesons taking into account the internal quark dynamics. The neutral states are labelled by two-dimensional momenta for magnetic translations, while the charged states by two discrete indices related to angular momenta. For $B\ll {\Lambda }_{\mathrm{QCD}}^2$ (${\Lambda }_{\mathrm{QCD}}\sim 200$ MeV: the QCD scale), the analyses proceed as in usual quark models, while special precautions are needed for strong fields, $B\sim {\Lambda }_{QCD}^2$, especially when we treat short range correlations such as the Fermi-Breit-Pauli interactions. We compute the energy spectra of mesons up to energies of $\sim 2.5$ GeV and use them to construct the meson resonance gas. Within the assumption that the constituent quark masses are insensitive to magnetic fields, the phase space enhancement for mesons significantly increases the entropy, assisting a transition from a hadron gas to a quark gluon plasma. We confront our results with the lattice data, finding reasonable agreement for the low-lying spectra and the entropy density at low temperature less than $\sim 100$ MeV, but our results at higher energy scale suffer from artifacts of our confining potential and non-relativistic treatments.

   hep-phhep-latnucl-thEPJA(2021)·25 citations
7. 07*

   CP-Violating and Charged Current Neutrino Non-standard Interactions in CE$\nu$NS

   Amir N. Khan🇩🇪 · Douglas W. McKay🇺🇸 · Werner Rodejohann🇩🇪

   Neutrino non-standard interactions (NSI) can be constrained using coherent elastic neutrino-nucleus scattering. We discuss here two aspects in this respect, namely the effects of (i) charged current NSI in neutrino production and (ii) CP-violating phases associated with neutral current NSI in neutrino detection. Effects of CP-phases require the simultaneous presence of two different flavor-changing neutral current NSI parameters. Applying these two scenarios to the COHERENT measurement, we derive limits on charged current NSI and find that more data is required to compete with the existing limits. Regarding CP-phases, we show how the limits on the NSI parameters depend dramatically on the values of the phases. Accidentally, the same parameters influencing coherent scattering also show up in neutrino oscillation experiments. We find that COHERENT provides complementary constraints on the set of NSI parameters that can explain the discrepancy in the best-fit value of the standard CP-phase obtained by T2K and NO$\nu$A, while the significance with which the LMA-Dark solution is ruled out can be weakened by the presence of additional NSI parameters introduced here.

   hep-phhep-exPRD(2021)·27 citations
8. 08*

   Spectroscopic Investigation of Light Strange S=-1 $\Lambda$, $\Sigma$ and S=-2 $\Xi$ Baryons

   Chandni Menapara🇮🇳 · Ajay Kumar Rai🇮🇳

   The present study is dedicated to light-strange $\Lambda$ with strangeness S=-1, isospin I=0; $\Sigma$ with S=-1, I=1 and $\Xi$ baryon with S=-2 and $I=\frac{1}{2}$. In this article, hypercentral Constituent Quark Model with linear confining potential has been employed along with first order correction term to obtain the resonance masses for nearly upto 4 GeV. The calculated states include 1S-5S, 1P-4P, 1D-3D, 1F-2F and 1G (in few case) along with all the possible spin-parity assignments. Regge Trajectories have been explored for the linearly of the calculated masses for $(n,M^2)$ and $(J,M^2)$ respectively. Magnetic moments have been intensively studied for ground state spin $\frac{1}{2}$ and $\frac{3}{2}$, in addition to the configuration mixing for first negative parity state for $\Xi$. Lastly, transition magnetic moment and radiative decay width have been presented.

   hep-phCPC(2021)·43 citations
9. 09*

   Revisiting Hadronic Mass Relations from First Order Flavor Symmetry Breaking

   Luiz Frederic Wagner🇩🇪

   The Gell-Mann$-$Okubo (GMO) mass relations following from $\text{SU}(3)$-flavor symmetry breaking in the strong sector have been proven to be of great success for describing hadron masses and classifying them into multiplets. Nowadays, it is widely believed that baryons being fermions have to obey GMO relations which are linear in the baryon masses, whilst mesons as bosons follow quadratic GMO relations. In this work, I challenge the distinction of GMO relations for baryons and mesons and conclude that both linear and quadratic GMO relations apply to both baryons and mesons in most instances (exceptions are the pseudoscalar meson octet and the mass relations following from heavy quark symmetry). I support this claim by presenting an in-depth analysis of the GMO relations on a theoretical and experimental level. On the theoretical side, two approaches to the derivation of the GMO relations are given and isospin symmetry breaking, electromagnetic contributions, and heavy quark symmetry are incorporated into the mass relations. Both linear and quadratic mass relations are checked against experimentally determined hadron masses. Furthermore, the mass relations are used to classify unassigned resonances like ${\Lambda }_c^{+}(2940)$ and ${\Xi }_c(3123)$ into multiplets and to predict the masses of missing particles in yet incomplete multiplets.

   hep-ph0 citations
10. 10*

    Future projections on the anomalous $WW\gamma \gamma$ couplings in hadron-hadron interactions at the FCC-hh

    A. Gutiérrez-Rodríguez🇲🇽 · V. Ari🇹🇷 · E. Gurkanli🇹🇷 · M. Köksal🇹🇷 · M. A. Hernández-Ruíz🇲🇽

    We carry out a study in the approach of a dimension-8 effective field theory on the anomalous quartic $WW\gamma \gamma$ couplings that arise from the process $pp\to W\gamma \gamma$ at the Future Circular Collider-hadron hadron (FCC-hh). The process is sensitive to the $WW\gamma \gamma$ vertex, and future projections on the anomalous $f_{M,i}/{\Lambda }^4$ and $f_{T,j}/{\Lambda }^4$ couplings can be put by measurements of $W\gamma \gamma$ production. We illustrate the physics opportunities and reach of the FCC-hh operating for a high integrated luminosity scenario of $\mathcal{L}=1,5,10,30$ ${\mathrm{ab}}^{-1}$ of proton-proton collisions at a center-of-mass energy of $\sqrt{s}=100$ TeV and systematic uncertainties of ${\delta }_{sys}=0\%,3\%,5\%,10\%$. Production cross-sections of the signal and the sensitivity constraints on the anomalous $f_{M,i}/{\Lambda }^4$ and $f_{T,j}/{\Lambda }^4$ couplings at $95\%$ C.L. are identified through the leptonic and hadronic decay modes of the $W$-boson. The FCC-hh sensitivity on these anomalous couplings is expected might reach up to the order of magnitude $\mathcal{O}(10^{-4}-10^1)$. These sensitivity perspectives indicate that the $pp\to W\gamma \gamma$ channel at the FCC-hh has a greater potential to search for the anomalous quartic $WW\gamma \gamma$ couplings and to search for new physics than present colliders.

    hep-phJ.Phys.G(2022)·12 citations
11. 11*

    Sensitivity analysis for the anomalous $W^{+}{W}^{-}\gamma$ couplings at the LHeC and the FCC-he

    S. Spor🇹🇷 · M. Köksal🇹🇷

    We study the anomalous $W^{+}{W}^{-}\gamma$ couplings in performing the production of the W-pair through the process $e^{-}p\to e^{-}{\gamma }^{\ast }{\gamma }^{\ast }p\to e^{-}{W}^{+}{W}^{-}p$ at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). We examine the pure hadronic, the semi-leptonic and the pure leptonic decay channels of the produced W-pair. We assume the center-of-mass energies of $\sqrt{s}=1.30$ and $1.98$ TeV and the integrated luminosities of 10-100 fb${}^{-1}$ for the LHeC and the center-of-mass energies of $\sqrt{s}=3.46$ and $5.29$ TeV and the integrated luminosities of 100-2000 fb${}^{-1}$ for the FCC-he. The best limits at 95$\%$ confidence level obtained for the anomalous couplings $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ are $\Delta {\kappa }_{\gamma }=[-0.00208;0.00206]$ and ${\lambda }_{\gamma }=[-0.00174;0.00834]$. By comparing these limits with the experimental limits, we present the potentials of the process and future $ep$ colliders.

    hep-phEur.Phys.J.Plus(2022)·7 citations
12. 12*

    Chiral gravitational effect in time-dependent backgrounds

    Kohei Kamada🇯🇵 · Jun'ya Kume🇯🇵 · Yusuke Yamada🇯🇵

    Gravitational counterpart of the chiral magnetic effect, which is referred as the chiral gravitational effect, can also be of interest in a cosmological setup. In this study, we investigate this effect in the time-dependent chiral asymmetric fermion background and in the expanding spacetime by formulating the effective action of gravitational waves. We also analyze the anomaly equation to see how the backreaction from gravitational waves to thermal chiral plasma occurs. We find that the non-trivial time dependence of chiral chemical potential, which can be induced in some scenarios of baryogenesis, is the key ingredient of the chiral gravitational effect. It turns out that the "memory" of the effect is imprinted on the high frequency gravitational waves propagating in the plasma. Cosmological implications and potential effects on the gravitational wave observation are briefly discussed.

    hep-phastro-ph.COgr-qchep-thJHEP(2021)·15 citations
13. 13*

    A New Approach to Electroweak Symmetry Non-Restoration

    Marcela Carena🇺🇸 · Claudius Krause🇺🇸 · Zhen Liu🇺🇸 · Yikun Wang🇺🇸

    Electroweak symmetry non-restoration up to high temperatures well above the electroweak scale offers new alternatives for baryogenesis. We propose a new approach for electroweak symmetry non-restoration via an inert Higgs sector that couples to the Standard Model Higgs as well as an extended scalar singlet sector. We implement renormalization group improvements and thermal resummation, necessary to evaluate the effective potential spanning over a broad range of energy scales and temperatures. We present examples of benchmark scenarios that allow for electroweak symmetry non-restoration all the way up to hundreds of TeV temperatures, and also feature suppressed sphaleron washout factors down to the electroweak scale. Our method for transmitting the Standard Model broken electroweak symmetry to an inert Higgs sector has several intriguing implications for (electroweak) baryogenesis, early universe thermal histories, and can be scrutinized through Higgs physics phenomenology and electroweak precision measurements at the HL-LHC.

    hep-phPRD(2021)·45 citations
14. 14*

    Magnetic monopole in a chiral plasma: chiral dyon

    Michael Lublinsky🇮🇱 · Jared Reiten🇺🇸 · Andrey V. Sadofyev🇪🇸

    The placement of a magnetic monopole into an electrically-neutral chiral plasma with a non-zero axial density results in an electric polarization of the matter. The electric current produced by the chiral magnetic effect is balanced by charge diffusion and Ohmic dissipation, which generates a non-trivial charge distribution. In turn, the latter induces a separation of chiralities along the magnetic field of the monopole due to the chiral separation effect. We find the stationary states of such a system, with vanishing total electric current and stationary axial current balanced by the chiral anomaly. In this solution, the monopole becomes "dressed" with an electric charge that is proportional to the averaged chiral density of the matter -- forming a chiral dyon. The interplay between the chiral effects on the one hand, and presence of magnetic field of the monopole on the other, may affect the evolution of the monopole density in the early Universe, contribute to the process of baryogenesis, and can also be instrumental for detection of relic monopoles using chiral materials.

    hep-phhep-thnucl-thPRD(2021)·0 citations
15. 15*

    Conformal transformations of conservation equations in spin hydrodynamics

    Rajeev Singh🇵🇱

    We study and analyse the conformal transformations of different conservation laws in the spin hydrodynamics framework.

    hep-phgr-qchep-thnucl-thActa Phys.Polon.B(2021)·3 citations
16. 16*

    New Constraints on Lorentz Invariance Violation from Combined Linear and Circular Optical Polarimetry of Extragalactic Sources

    Roman Gerasimov🇺🇸 · Praneet Bhoj🇺🇸 · Fabian Kislat🇺🇸

    Expanding on our prior efforts to search for Lorentz invariance violation (LIV) using the linear optical polarimetry of extragalactic objects, we propose a new method that combines linear and circular polarization measurements. While existing work has focused on the tendency of LIV to reduce the linear polarization degree, this new method additionally takes into account the coupling between photon helicities induced by some models. This coupling can generate circular polarization as light propagates, even if there is no circular polarization at the source. Combining significant detections of linear polarization of light from extragalactic objects with the absence of the detection of circular polarization in most measurements results in significantly tighter constraints regarding LIV. The analysis was carried out in the framework of the Standard-Model Extension (SME), an effective field theory framework to describe the low-energy effects of an underlying fundamental quantum gravity theory. We evaluate the performance of our method by deriving constraints on the mass dimension $d=4$ CPT-even SME coefficients from a small set of archival circular and linear optical polarimetry constraints and compare them to similar constraints derived in previous works with far larger sample sizes and based on linear polarimetry only. The new method yielded constraints that are an order of magnitude tighter even for our modest sample size of 21 objects. Based on the demonstrated gain in constraining power from scarce circular data, we advocate for the need for future extragalactic circular polarization surveys.

    ↳ astro-ph.COastro-ph.HEhep-phSymmetry(2021)·15 citations
17. 17*

    Conformal Symmetry in Momentum Space and Anomaly Actions in Gravity

    Matteo Maria Maglio🇮🇹

    In this thesis we study the momentum space approach to the solution of the CWI's of CFT's in higher dimensions. Our work's goal is to illustrate the essential steps needed to build tensor correlators starting from the scalar solutions, for 3-point functions. In the case of 4-point functions, our attention is centred around scalar correlators for which the CWI's are sufficient to isolate the unique solution if we enhance the symmetry with the addition of a dual conformal symmetry. Dual conformal symmetry in momentum space is obtained once the momentum variables are rewritten in a dual form, as the difference of coordinate-like variables and treated as ordinary correlators in such variables, mirroring the action of coordinate space. This enhancement of the symmetry is sufficient to fix the solutions also for such correlators. The solution of the conformal constraints are given in terms of triple-$K$ integrals and are expressed in terms of a set of constants, specific for each correlator and spacetime dimension. We present a discussion of the intermediate steps in the description of two nontrivial correlators, the $TTO$ and the $TTT$, in a more pedagogical way, offering details that could help extend such methods to higher point function.

    ↳ hep-thhep-phmath-phmath.MP2 citations
18. 18*

    Constraints on ${\Xi }^{-}$ nuclear interactions from capture events in emulsion

    E. Friedman🇮🇱 · A. Gal🇮🇱

    Five ${\Xi }^{-}p\to \Lambda \Lambda$ two-body capture events in ${}^{12}$C and ${}^{14}$N emulsion nuclei, in which a pair of single-$\Lambda$ hypernuclei is formed and identified by their weak decay, have been observed in $(K^{-},K^{+})$ emulsion exposures at KEK and J-PARC. Applying a ${\Xi }^{-}$-nucleus optical potential methodology to study atomic and nuclear transitions, we confirm that these capture events occur from Coulomb assisted $1p_{{\Xi }^{-}}$ nuclear states. Long-range $\Xi N$ shell-model correlations are found essential to achieve consistency between the ${}^{12}$C and ${}^{14}$N events. The resulting $\Xi$-nuclear interaction is strongly attractive, with $\Xi$ potential depth in nuclear matter $V_{\Xi }\gtrsim 20$ MeV. Implications to multi-strangeness features of dense matter are outlined.

    ↳ nucl-thhep-phnucl-exPLB(2021)·49 citations
19. 19*

    Contracting Cosmologies and the Swampland

    Heliudson Bernardo🇨🇦 · Robert Brandenberger🇨🇦

    We consider the cosmology obtained using scalar fields with a negative potential energy, such as employed to obtain an Ekpyrotic phase of contraction. Applying the covariant entropy bound to the tower of states dictated by the distance conjecture, we find that the relative slope of the potential $|V^{\prime }|/|V|$ is bounded from below by a constant of the order one in Planck units. This is consistent with the requirement to obtain slow Ekpyrotic contraction. We also derive a refined condition on the potential which holds near local minima of a negative potential.

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

    Negative temperature: further extensions

    G.E. Volovik🇫🇮

    This paper is motivated by the recent paper M. Baldovin, S. Iubini, R. Livi and A. Vulpiani, Statistical mechanics of systems with negative temperature, arXiv:2103.12572. The authors suggest that negative absolute temperatures are consistent with equilibrium thermodynamics. This is correct, if the environment also has negative temperature. Otherwise such states represent the transient though maybe long-lived metastable effects. Here we consider the extension of the negative temperatures to the relativistic systems. We show that the negative state is possible in the Dirac vacuum, which is obtained by the $PT$ symmetry transformation from the conventional Dirac sea. If such vacuum with inverse population fills the whole Universe, its thermodynamics determined by negative temperatures becomes equilibrium.

    ↳ gr-qccond-mat.otherhep-phJETP Lett.(2021)·6 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.