Wed·Jan 5, 2022Wednesday·January 5, 2022

1. 01*

   One-Loop Matching Conditions in Neutrino Effective Theory

   Tommy Ohlsson🇸🇪 · Marcus Pernow🇸🇪

   We investigate matching conditions and threshold corrections between full and effective theories based on the type I seesaw mechanism. In general, using an intuitive Feynman diagrammatical approach, we compute the amplitudes before and after integrating out heavy right-handed neutrinos at the matching scale. In particular, we derive the one-loop matching conditions between the full and the effective theories. The matching conditions of the parameters are influenced by one-loop corrections to the corresponding vertices as well as wave function corrections for the Higgs and the lepton fields. Our results are comparable to earlier results based on a functional approach.

   hep-phNPB(2022)·14 citations
2. 02*

   Imprints of MeV Scale Hidden Dark Sector at Planck Data

   Sougata Ganguly🇮🇳 · Sourov Roy🇮🇳 · Abhijit Kumar Saha🇮🇳

   New light species can contribute to the number of effective relativistic degrees of freedom ($N_{\mathrm{eff}}$) at Cosmic Microwave Background (CMB) which is precisely measured by Planck. In this work, we consider an MeV scale thermally decoupled non-minimal dark sector and study the imprint of the dark sector dynamics on the measurement of $N_{\mathrm{eff}}$ at the time of CMB formation. We have predicted the allowed region of model parameter space in the light of constraints arising from the measurements of both $N_{\mathrm{eff}}$ and dark matter relic density by Planck. It turns out that the impact of the dark sector dynamics on $N_{\mathrm{eff}}$ is significant in case of a non-hierarchical mass spectrum of the dark sector particles.

   hep-phPLB(2022)·6 citations
3. 03*

   Quasi-Sterile Neutrinos from Dark Sectors I. BSM matter effects in neutrino oscillations and the short-baseline anomalies

   Daniele S. M. Alves🇺🇸 · William C. Louis🇺🇸 · Patrick G. deNiverville🇺🇸

   Quasi-sterile neutrinos are a natural consequence of dark sectors interacting with the Standard Model (SM) sector via neutrino- and vector-portals. Essentially, quasi-sterile neutrinos are light dark sector fermions with two generic properties: (i) they mix with the active neutrinos of the SM, and (ii) they are charged under a vector mediator that couples feebly to SM matter. Various interesting phenomenological consequences result from this class of particles. In this article, we investigate one such consequence: new, beyond the SM matter effects that can alter in-medium neutrino oscillations. In particular, for special windows of energy and matter densities, active neutrinos can resonantly oscillate into sterile neutrinos. We take advantage of this feature to build a quasi-sterile neutrino model that can explain the MiniBooNE and LSND anomalies, while remaining compatible with observations from long-baseline reactor- and accelerator-based neutrino experiments. This model is also likely compatible with the recent results reported by the MicroBooNE collaboration (albeit we cannot precisely quantify this claim due to a lack of information in MicroBooNE's public data releases to date). Implications for solar neutrinos and ${\nu }_e$ disappearance searches are also briefly discussed.

   hep-phhep-exJHEP(2022)·10 citations
4. 04*

   Emergence of pion parton distributions

   Z.-F. Cui🇨🇳 · M. Ding🇩🇪 · J. M. Morgado🇪🇸 · K. Raya🇪🇸 · D. Binosi🇮🇹 · L. Chang🇨🇳 · F. De Soto🇪🇸 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇪🇸 · S. M. Schmidt🇩🇪

   Supposing only that there is an effective charge which defines an evolution scheme for parton distribution functions (DFs) that is all-orders exact, strict lower and upper bounds on all Mellin moments of the valence-quark DFs of pion-like systems are derived. Exploiting contemporary results from numerical simulations of lattice-regularised quantum chromodynamics (QCD) that are consistent with these bounds, parameter-free predictions for pion valence, glue, and sea DFs are obtained. The form of the valence-quark DF at large values of the light-front momentum fraction is consistent with predictions derived using the QCD-prescribed behaviour of the pion wave function.

   hep-phhep-exhep-latnucl-ex+1PRD(2022)·51 citations
5. 05*

   Neutrino bound states and bound systems

   Alexei Yu. Smirnov🇩🇪 · Xun-Jie Xu🇨🇳

   Yukawa interactions of neutrinos with a new light scalar boson $\varphi$ can lead to formation of stable bound states and bound systems of many neutrinos ($\nu$-clusters). For allowed values of the coupling $y$ and the scalar mass $m_{\varphi }$, the bound state of two neutrinos would have the size larger than $10^{12}$ cm. Bound states with sub-cm sizes are possible for keV scale sterile neutrinos with coupling $y>10^{-4}$. For $\nu$-clusters we study in detail the properties of final stable configurations. If there is an efficient cooling mechanism, these configurations are in the state of degenerate Fermi gas. We formulate and solve equations of the density distributions in $\nu$-clusters. In the non-relativistic case, they are reduced to the Lane-Emden equation. We find that (i) stable configurations exist for any number of neutrinos, $N$; (ii) there is a maximal central density $\sim 10^9$ cm${}^{-3}$ determined by the neutrino mass; (iii) for a given $m_{\varphi }$ there is a minimal value of $N{y}^3$ for which stable configurations can be formed; (iv) for a given strength of interaction, $S_{\varphi }=(y{m}_{\nu }/m_{\varphi }{)}^2$, the minimal radius of $\nu$-clusters exists. We discuss the formation of $\nu$-clusters from relic neutrino background in the process of expansion and cooling of the Universe. One possibility realized for $S_{\varphi }>700$ is the development of instabilities in the $\nu$-background at $T<m_{\nu }$ which leads to its fragmentation. For allowed values of $y$, cooling of $\nu$-clusters due to $\varphi$-bremsstrahlung and neutrino annihilation is negligible. The sizes of $\nu$-clusters may range from $\sim$ km to $\sim 5$ Mpc. Formation of clusters affects perspectives of detection of relic neutrinos.

   hep-phastro-ph.COJHEP(2022)·44 citations
6. 06*

   Electromagnetic properties of doubly heavy pentaquark states

   U. Ozdem🇹🇷

   Motivated by the latest discovery of doubly-charmed tetraquark $T_{cc}^{+}$ by LHCb collaboration, we have studied the magnetic moments of the possible doubly-heavy pentaquark states with quantum numbers $J^P=1/2^{-}$ and $J^P=3/2^{-}$ within the light-cone sum rules method. In the analysis, these possible pentaquark states are considered in diquark-diquark-antiquark structure. The magnetic moments of hadrons encode helpful details about the distributions of the charge and magnetization inside the hadrons, which help us to figure out their geometric configurations. As a by product, the electric quadrupole and magnetic octupole moments of the spin-3/2 doubly-heavy pentaquark states are also extracted. These values show a non-spherical charge distribution. It will be interesting and useful to examine the magnetic moments of these possible doubly-heavy pentaquark states with different theoretical approaches.

   hep-phhep-exhep-latEur.Phys.J.Plus(2022)·31 citations
7. 07*

   Oblique parameters of BSM models with three CP-even neutral scalars

   Swagata Ghosh🇮🇳

   We express the oblique parameters $S$, $T$, $U$, $V$, $W$, and $X$ in terms of the corresponding mixing matrices in the framework of three BSM models with three CP-even neutral scalars. We consider three types of the extension of the scalar sector of the SM with non-standard (i) two real singlet scalars, (ii) one complex doublet and one real singlet scalar, and (iii) two complex doublets. We present the expressions such that one can use these when all the neutral CP-even scalars have VEV, or one of them does not have any VEV. The principal benifit of presenting the oblique parameters in this way is, the sole knowledge of the mixing matrices in the corresponding scalar sector is enough to extract the expression of the oblique parameter of that particular BSM model. This paper also presents some plots, for reference, showing the allowed region of the masses of the three CP-even neutral scalars and the three mixing angles of the three above-mentioned models.

   hep-ph2 citations
8. 08*

   Universal Energy Dependence of Measured Temperatures for Baryons Produced in Heavy-ion Collisions

   Lilin Zhu🇨🇳 · Hua Zheng🇨🇳 · Ke Da🇨🇳 · Huanjing Gong🇨🇳 · Zhizhen Ye🇨🇳 · Guiqi Liu🇨🇳 · Rudolph C. Hwa🇺🇸

   From the data on baryon production in heavy-ion collisions it is shown that a set of measurable functions exist, one for each baryon type, that depend exponentially on transverse momenta up to the maximum values detected for all collision energies ranging from the low end of RHIC BES to the high end of CERN LHC. The implied temperatures satisfy a scaling law in collision energy with a universal exponent for all baryon types which is the novel discovery. A self-similar thermal source is implied. Furthermore, it is shown how the scaling behavior depends on centralities. Those features in the data are related to simple properties of light and strange quarks by use of the recombination model. Prediction of $\varphi$ meson production is made and then verified by existing data.

   hep-phhep-exPRC(2023)·6 citations
9. 09*

   Influence of QCD parton shower in deep learning invisible Higgs through vector boson fusion

   Partha Konar🇮🇳 · Vishal S. Ngairangbam🇮🇳

   Vector boson fusion established itself as a highly reliable channel to probe the Higgs boson and an avenue to uncover new physics at the Large Hadron Collider. This channel provides the most stringent bound on Higgs' invisible decay branching ratio, where the current upper limits are significantly higher than the one expected in the Standard Model. It is remarkable that merely low-level calorimeter data from this characteristically simple process can improve this limit substantially by employing sophisticated deep-learning techniques. The construction of such neural networks seems to comprehend the event kinematics and radiation pattern exceptionally well. However, the full potential of this outstanding capability also warrants a precise theoretical projection of QCD parton showering and corresponding radiation pattern. This work demonstrates the relation using different recoil schemes in the parton shower with leading order and higher-order computation.

   hep-phPRD(2022)·5 citations
10. 10*

    Flavour violating charged lepton decays in Little Randall-Sundrum Model

    Akshay A🇮🇳 · Mathew Thomas Arun🇮🇳

    The Little Randall-Sundrum (Little RS) model receives significantly stronger constraints from the flavour observables in comparison to Randall-Sundrum (RS) model. In this paper, we analyse the effect of the electro-weak sector in Little RS on flavour changing decays of charged leptons. We compare the predictions of the model with the current limits on the flavour violating Branching Ratios of $\mu \to eee$, $\tau \to eee$, $\tau \to \mu \mu \mu$, $\tau \to \mu ee$, $\tau \to e\mu \mu$ , $\mu \to e\gamma$, and $\mu Ti\to eTi$. And we show that the dominant constraint arises from the $\mu Ti\to eTi$ process which strongly limits the KK-1 gauge boson mass ($M_{KK}$) to be $\gtrsim 30.7TeV$. We then derive and show that generalising the electro-weak gauge sector to include the Brane Localised Kinetic Term (BLKT) relaxes this constraint to $\gtrsim 12TeV$. Towards the conclusion, we comment on the possibility that the large flavour violating currents can be mitigated by relaxing the assumption regarding the unnatural thinness and rigidity of the UV-brane and discuss the possibility of suppression of these currents in presence of fat fluctuating branes.

    hep-phhep-thPRD(2023)·2 citations
11. 11*

    Spectroscopic Properties of $B$ and $B_s$ meson using Screened Potential

    Vikas Patel🇮🇳 · Raghav Chaturvedi🇮🇳 · A. K. Rai🇮🇳

    Inspired by the recent observations of $B$ and $B_s$ meson states at LHCb\cite{Aaij:2020hcw} we calculate the masses of ground, orbitally, and radially excited states. Also, we estimate the mixing parameters, decay constant, leptonic decay width, and corresponding branching ratios, as well as electromagnetic transition widths. $\mathcal{O}\left(\frac{1}{m}\right)$ and $\mathcal{O}(p^{10})$ relativistic corrections to potential and kinetic energy terms have been added to the Hamiltonian. The screening potential employed is solved by applying the gaussian wave function. The estimated masses are used to construct the Regge trajectories, which help us in the association of some newly observed states to $B$ and $B_s$ meson family. Overall, the results from the present study are in fair agreement with available experimental and theoretical studies.

    hep-ph11 citations
12. 12*

    Gauge-Higgs models from Nilmanifolds

    Aldo Deandrea🇫🇷 · Fabio Dogliotti🇫🇷 · Dimitrios Tsimpis🇫🇷

    We consider the compactification of a Yang-Mills theory on a three-dimensional nilmanifold. The compactification generates a Yang-Mills theory in four space-time dimensions, coupled to a specific scalar sector. The compactification geometry gives rise to masses for the zero-modes, proportional to the twist parameter of the nilmanifold. We study the simple example of an SU (3) model broken by a non-trivial vacuum of the scalar potential which generates three mass scales, two being at tree level, and the third one at loop level. We point out the relevance of general twisted geometries for model building and in particular for gauge-Higgs type models, as the twist generates tree-level mass hierarchies useful for grand unification and for the Higgs sector in electroweak symmetry breaking.

    hep-phhep-thPLB(2022)·4 citations
13. 13*

    Lattice simulations of the QCD chiral transition at real ${\mu }_B$

    Attila Pasztor🇭🇺 · Szabolcs Borsanyi🇩🇪 · Zoltan Fodor🇩🇪 · Matteo Giordano🇭🇺 · Sandor D. Katz🇭🇺 · Daniel Nogradi🇭🇺 · Chik Him Wong🇩🇪

    Most lattice studies of hot and dense QCD matter rely on extrapolation from zero or imaginary chemical potentials. The ill-posedness of numerical analytic continuation puts severe limitations on the reliability of such methods. We studied the QCD chiral transition at finite real baryon density with the more direct sign reweighting approach. We simulate up to a baryochemical potential-temperature ratio of ${\mu }_B/T=2.7$, covering the RHIC Beam Energy Scan range, and penetrating the region where methods based on analytic continuation are unpredictive.This opens up a new window to study QCD matter at finite ${\mu }_B$ from first principles.

    ↳ hep-lathep-phnucl-thSciPost Phys.Proc.(2022)·0 citations
14. 14*

    Entropy constraints on effective field theory

    Qing-Hong Cao🇨🇳 · Daiki Ueda🇨🇳

    In effective field theory, the positivity bounds of higher derivative operators are derived from analyticity, causality, and unitarity. We show that the positivity bounds on some operators of the effective field theory, e.g., dimension-eight term of a single massless scalar field, the Standard Model Effective Field Theory dimension-eight $SU(N)$ gauge bosonic operators, and higher-derivative operators in the Einstein-Maxwell theory, generated by interactions between heavy and light degrees of freedom can be derived by the non-negativity of relative entropy. For such effective field theories, we prove that the interactions increase thermodynamic entropy at a fixed charge and an extremal point of energy, which is intimately connected with the extremality relations of black holes exhibiting Weak-Gravity-Conjecture. These arguments are applicable when corrections from the interactions involving higher-derivative operators of light fields are not dominant in the effective field theories. The entropy constraint is a consequence of the Hermiticity of Hamiltonian, and any theory violating the non-negativity of entropy would not respect the second law of thermodynamics.

    ↳ hep-thhep-phquant-phPRD(2023)·19 citations
15. 15*

    The single-particle space-momentum angle distribution effect on two-pion HBT correlation with the Coulomb interaction

    Hang Yang🇨🇳 · Qichun Feng🇨🇳 · Jingbo Zhang🇨🇳

    We calculate the HBT radius Rs for {\pi}+ particles with the Coulomb interaction by using the string melting version of a multiphase transport(AMPT) model. We study the relationship between the single-particle space-momentum angle and the particle sources and discuss HBT radii without single-particle space-momentum correlation. Additionally, we study the Coulomb interaction effect on the numerical connection between the single-particle space-momentum angle distribution and the transverse momentum dependence of Rs.

    ↳ nucl-thhep-phCPC(2022)·0 citations
16. 16*

    Limits on primordial black holes detectability with Isatis: A BlackHawk tool

    Jérémy Auffinger🇫🇷

    Primordial black holes (PBHs) are convenient candidates to explain the elusive dark matter (DM). However, years of constraints from various astronomical observations have constrained their abundance over a wide range of masses, leaving only a narrow window open at $10^{17}\mathrm{g}\lesssim M\lesssim 10^{22}$g for all DM in the form of PBHs. We reexamine this disputed window with a critical eye, interrogating the general hypotheses underlying the direct photon constraints. We review 4 levels of assumptions: i) instrument characteristics, ii) prediction of the (extra)galactic photon flux, iii) statistical method of signal-to-data comparison and iv) computation of the Hawking radiation rate. Thanks to Isatis, a new tool designed for the public Hawking radiation code BlackHawk, we first revisit the existing and prospective constraints on the PBH abundance and investigate the impact of assumptions i)-iv). We show that the constraints can vary by several orders of magnitude, advocating the necessity of a reduction of the theoretical sources of uncertainties. Second, we consider an "ideal" instrument and we demonstrate that the PBH DM scenario can only be constrained by the direct photon Hawking radiation phenomenon below $M_{\max }\sim 10^{20}$g. The upper part of the mass window should therefore be closed by other means.

    ↳ astro-ph.HEastro-ph.COgr-qchep-ph+1EPJC(2022)·26 citations
17. 17*

    On the nature of radio-wave radiation from particle cascades

    Clancy W. James🇦🇺

    The nature of the radio-wave radiation generated by particle cascades in both the Earth's atmosphere and dense media such as ice has, historically, been much debated. This situation changed in the early 2010's, with the community converging on the common terminology of "geomagnetic" and "Askaryan" radiation to describe the two emission mechanisms. However, this convergence arose from discussions at various conferences and workshops, and was ultimately reached through agreement between simulation codes and experimental measurements. In this article therefore, I use relatively simple geometrical arguments, and a minimum of calculations based on single particle tracks, to explain the nature of radiation from extensive air showers (EAS) and cascades in dense media such as ice. I identify well-determined frequency regimes where the radiation from the Askaryan effect will be bremsstrahlung-like and Cherenkov-like, being respectively below/above 1 GHz in EAS and 100 MHz in dense media; and where geomagnetic emission will be transverse-current-like and where it will resemble synchrotron radiation, respectively below/above a few GHz in EAS, depending on the height of cascade development. I suggest how these transitions in the nature of the emission may be experimentally observed.

    ↳ astro-ph.HEastro-ph.IMhep-exhep-phPRD(2022)·24 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.