Wed·Apr 21, 2021Wednesday·April 21, 2021

1. 01*

   Vacuum Stability vs. Positivity in Real Singlet Scalar Extension of the Standard Model

   Parsa Ghorbani🇮🇷

   We assume a generic real singlet scalar extension of the Standard Model living in the vacuum $(v,w)$ at the electroweak scale with $v=246$ GeV and $w$ being respectively the Higgs and the singlet scalar vacuum expectation values. By requiring {\it absolute} vacuum stability for the vacuum $(v,w)$, the positivity condition and the perturbativity up to the Planck scale, we show that the viable space of parameters in the model is strongly constrained for various singlet scalar vacuum expectation values $w=0.1,1,10,100$ TeV. Also, it turns out that the singlet scalar mass can be from a few GeV up to less than TeV.

   hep-phhep-thNPB(2021)·22 citations
2. 02*

   Lepton Flavour Violation in a radiative neutrino mass model with the asymmetric Yukawa structure

   Yoko Irie🇯🇵 · Osamu Seto🇯🇵 · Tetsuo Shindou🇯🇵

   Though models with the radiative neutrino mass generation are phenomenologically attractive, the complicated relationship between the flavour structure of additional Yukawa matrices and the neutrino mass matrix sometimes is a barrier to explore the models. We introduce a simple prescription to analyze the relation in a class of models with the asymmetric Yukawa structure. We then apply the treatment to the Zee-Babu model as a concrete example of the class and discuss the phenomenological consequences of the model. The combined studies among the neutrino physics, the lepton flavour violation, and the search for the new particles at the collider experiments provide the anatomy of the Zee-Babu model.

   hep-phPLB(2021)·6 citations
3. 03*

   Searches for new physics at SND@LHC

   Alexey Boyarsky🇳🇱 · Oleksii Mikulenko🇳🇱 · Maksym Ovchynnikov🇳🇱 · Lesya Shchutska🇨🇭

   SND@LHC is an approved experiment equipped to detect scattering of neutrinos produced in the far-forward direction at the LHC, and aimed to measure their properties. In addition, the detector has a potential to search for new feebly interacting particles (FIPs) that may be produced in proton-proton collisions. In this paper, we discuss FIPs signatures at SND@LHC considering two classes of particles: stable FIPs that may be detected via their scattering, and unstable FIPs that decay inside the detector. We estimate the sensitivity of SND@LHC to probe scattering of leptophobic dark matter, and to detect decays of neutrino, scalar, and vector portal particles. Finally, we also compare and qualitatively analyze the potential of SND@LHC and FASER/FASER{\nu} experiments for these searches.

   hep-phhep-exJHEP(2022)·57 citations
4. 04*

   Constraints on axionic fuzzy dark matter from light bending and Shapiro time delay

   Tanmay Kumar Poddar🇮🇳

   Ultralight axion like particles (ALPs) of mass $m_a\in (10^{-21}\mathrm{eV}-10^{-22}\mathrm{eV})$ with axion decay constant $f_a\sim 10^{17}\mathrm{GeV}$ can be candidates for fuzzy dark matter (FDM). If celestial bodies like Earth and Sun are immersed in a low mass axionic FDM potential and if the ALPs have coupling with nucleons then the coherent oscillation of the axionic field results a long range axion hair outside of the celestial bodies. The range of the axion mediated Yukawa type fifth force is determined by the distance between the Earth and the Sun which fixes the upper bound of the mass of axion as $m_a\lesssim 10^{-18}\mathrm{eV}$. The long range axionic Yukawa potential between the Earth and Sun changes the gravitational potential between them and contribute to the light bending and the Shapiro time delay. From the observational uncertainties of those experiments, we put an upper bound on the axion decay constant as $f_a\lesssim 9.85\times 10^6\mathrm{GeV}$, which is the stronger bound obtained from Shapiro time delay. This implies if ALPs are FDM, then they do not couple to nucleons.

   hep-phastro-ph.COgr-qchep-thJCAP(2021)·21 citations
5. 05*

   The effective radius for production of baryon-antibaryon pairs from $\psi$ decays

   Shu-Ming Wu🇨🇳 · Jia-Jun Wu🇨🇳 · Bing-Song Zou🇨🇳

   By using the covariant L-S Scheme for the partial wave analysis, we deduce the ratios between the S-wave and D-wave contributions from the recent data of $\psi (1^{-})\to B_8(1/2^{+}){\bar{B}}_8(1/2^{-})$ from the BESIII collaboration. For the $J/\psi \to \Lambda \bar{\Lambda }$ and $J/\psi (\psi (2S))\to {\Sigma }^{+}{\bar{\Sigma }}^{-}$, the ratios are fixed and the average angular momenta are computed to estimate the effective radii of these processes. The results show that the effective radii of these decays of $J/\psi (\psi (2S))$ are very small, which are around 0.04 fm. Thus, it is a nice place to search excited baryon resonances with lower spin in the decays of $J/\psi (\psi (2S))$. Furthermore, for the other $\psi (1^{-})\to B_8(1/2^{+}){\bar{B}}_8(1/2^{-})$ reactions, we propose some methods to get such effective radius.

   hep-phhep-exPRD(2021)·11 citations
6. 06*

   Scalar mesons and the fragmented glueball

   Eberhard Klempt🇩🇪

   The center-of-gravity rule is tested for heavy and light-quark mesons. In the heavy-meson sector, the rule is excellently satisfied. In the light-quark sector, the rule suggests that the $a_0(980)$ could be the spin-partner of $a_2(1320)$, $a_1(1260)$, and $b_1(1235)$; $f_0(500)$ the spin-partner of $f_2(1270)$, $f_1(1285)$, and $h_1(1170)$; and $f_0(980)$ the spin-partner of $f_2^{\prime }(1525)$, $f_1(1420)$, and $h_1(1415)$. From the decay and the production of light scalar mesons we find a consistent mixing angle ${\theta }^{\mathrm{s}}=(14\pm 4{)}^{\circ }$. We conclude that $f_0(980)$ is likely "octet-like" in SU(3) with a slightly larger $s\bar{s}$ content and $f_0(500)$ is SU(3) "singlet-like" with a larger $n\bar{n}$ component. The $a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1500)$ and $f_0(1370)$ are suggested as nonet of radial excitations. The scalar glueball is discussed as part of the wave function of scalar isoscalar mesons and not as additional "intruder". It seems not to cause supernumerosity.

   hep-phPLB(2021)·43 citations
7. 07*

   The Stochastic Axiverse

   Mario Reig🇪🇸

   In addition to spectacular signatures such as black hole superradiance and the rotation of CMB polarization, the plenitude of axions appearing in the string axiverse may have potentially dangerous implications. An example is the cosmological overproduction of relic axions and moduli by the misalignment mechanism, more pronounced in regions where the signals mentioned above may be observable, that is for large axion decay constant. In this work, we study the minimal requirements to soften this problem and show that the fundamental requirement is a long period of low-scale inflation. However, in this case, if the inflationary Hubble scale is lower than around $O(100)$ eV, no relic DM axion is produced in the early Universe. Cosmological production of some axions may be activated, via the misalignment mechanism, if their potential minimum changes between inflation and today. As a particular example, we study in detail how the maximal-misalignment mechanism dilutes the effect of dangerous axions and allows the production of axion DM in a controlled way. In this case, the potential of the axion that realises the mechanism shifts by a factor $\Delta \theta =\pi$ between the inflationary epoch and today, and the axion starts to oscillate from the top of its potential. We also show that axions with masses $m_a\sim O(1-100)H_0$ realising the maximal-misalignment mechanism generically behave as dark energy with a decay constant that can take values well below the Planck scale, avoiding problems associated to super-Planckian scales. Finally, we briefly study the basic phenomenological implications of the mechanism and comment on the compatibility of this type of maximally-misaligned quintessence with the swampland criteria.

   hep-phhep-thJHEP(2021)·39 citations
8. 08*

   Soft Gluon Resummation in Double Heavy Quarkonium Production at LHC

   Chong-Yang Lu🇨🇳 · Dan-Dan Shen🇨🇳 · Peng Sun🇨🇳 · Ruilin Zhu🇨🇳

   In this paper, the soft gluon resummation effect in double heavy quarkonium production at the LHC is studied. By applying the transverse momentum dependent factorization formalism, the large logarithms introduced by the small total transverse momentum of heavy quarkonium pair final state system, are resummed to all orders in the expansion of the strong interaction coupling at the Next-to-Leading Logarithm accuracy. We also compare our result with the LHC data. We find that the distribution shape predicted by resummation calculation is consistent with experimental data very well. Since this process is mainly initiated by gluon fusion, it supplies us an important channel to study the gluon parton property in hadrons.

   hep-phhep-ex2 citations
9. 09*

   More Indications for Lepton Nonuniversality in $b\to s{\ell }^{+}{\ell }^{-}$

   T. Hurth🇩🇪 · F. Mahmoudi🇨🇭 · D. Martinez Santos🇪🇸 · S. Neshatpour🇫🇷

   Recently the LHCb collaboration has confirmed the evidence for lepton flavour nonuniversality at the $3.1\sigma$ level via an updated measurement of $R_K$. In this work we analyse this evidence within a model-independent approach. We make projections for future measurements which indicate that LHCb will be in the position to discover lepton nonuniversality with the Run 3 data in a single observable. We analyse other ratios based on our analysis of the present measurements of the ratios $R_{K^{(\ast )}}$ and analyse if they are able to differentiate between various new physics options within the effective field theory at present or in the near future. We also compare the present deviations in the ratios with NP indications in the angular observables of exclusive $b\to s\ell \ell$ transitions. Finally, we update our global analysis considering all $b\to s\ell \ell$ observables altogether, including a 20-parameter fit in connection of a Wilks' test.

   hep-phPLB(2022)·147 citations
10. 10*

    Yukawa coupling unification in an $\mathsf{SO}(10)$ model consistent with Fermilab $(g-2{)}_{\mu }$ result

    Amin Aboubrahim🇩🇪 · Pran Nath🇺🇸 · Raza M. Syed🇦🇪

    We investigate the Yukawa coupling unification for the third generation in a class of $\mathsf{SO}(10)$ unified models which are consistent with the 4.2 $\sigma$ deviation from the standard model of the muon $g-2$ seen by the Fermilab experiment E989. A recent analysis in supergravity grand unified models shows that such an effect can arise from supersymmetric loops correction. Using a neural network, we further analyze regions of the parameter space where Yukawa coupling unification consistent with the Fermilab result can appear. In the analysis we take into account the contributions to Yukawas from the cubic and the quartic interactions. We test the model at the high luminosity and high energy LHC and estimate the integrated luminosities needed to discover sparticles predicted by the model.

    hep-phJHEP(2021)·28 citations
11. 11*

    Type-X two Higgs doublet model in light of the muon $\mathbf{g}-2$: confronting Higgs and collider data

    Adil Jueid🇰🇷 · Jinheung Kim🇰🇷 · Soojin Lee🇰🇷 · Jeonghyeon Song (Konkuk University, Korea)🇰🇷

    The recent Fermilab measurement of the muon anomalous magnetic moment yields $4.2\sigma$ deviations from the SM prediction when combined with the BNL E821 experiment results. In the Type-X two Higgs doublet model, we study the consequence of imposing the observed muon $g-2$, along with the constraints from theoretical stabilities, electroweak oblique parameters, Higgs precision data, and direct searches. For a comprehensive study, we scan the whole parameter space in two scenarios, the normal scenario where $h_{\mathrm{SM}}=h$ and the inverted scenario where $h_{\mathrm{SM}}=H$, where $h$ ($H$) is the light (heavy) CP-even Higgs boson. We found that large $\tan \beta$ (above 100) and light pseudoscalar mass $M_A$ are required to explain the muon $g-2$ anomaly. This breaks the theoretical stability unless the scalar masses satisfy $M_A^2\simeq M_{H^{\pm }}^2\simeq m_{12}^2\tan \beta \approx M_{H/h}^2$. The direct search bounds at the LEP and LHC exclude the light $A$ window with $M_A\lesssim 62.5$GeV. We also show that the observed electron anomalous magnetic moment is consistent with the model prediction, but the lepton flavor universality data in the $\tau$ and $Z$ decays are not. For a separate exploration of the model, we propose the golden mode $pp\to Ah/AH\to 4\tau$ at the HL-LHC.

    hep-phPRD(2021)·47 citations
12. 12*

    Is the Standard Model in the Swampland? Consistency Requirements from Gravitational Scattering

    Katsuki Aoki🇯🇵 · Tran Quang Loc🇬🇧 · Toshifumi Noumi🇯🇵 · Junsei Tokuda🇯🇵

    We study compatibility of the Standard Model of particle physics and General Relativity by means of gravitational positivity bounds, which provide a necessary condition for a low-energy gravitational theory to be UV completable within the weakly coupled regime of gravity. In particular, we identify the cutoff scale of the Standard Model coupled to gravity by studying consistency of light-by-light scattering. While the precise value depends on details of the Pomeron effects in QCD, the cutoff scale reads $10^{16}$GeV if the single-Pomeron exchange picture works well up to this scale. We also demonstrate that the cutoff scale is lowered to $10^{13}$GeV if we consider the electroweak theory without the QCD sector.

    ↳ hep-thgr-qchep-phPRL(2021)·43 citations
13. 13*

    Constraining Mixed Dark-Matter Scenarios of WIMPs and Primordial Black Holes from CMB and 21-cm observations

    Hiroyuki Tashiro🇯🇵 · Kenji Kadota🇰🇷

    We consider the dark matter (DM) scenarios consisting of the mixture of WIMPs and PBHs and study how much fraction of the total DM can be PBHs. In such scenarios, PBHs can accrete the WIMPs and consequently enhance the heating and ionization in the intergalactic medium due to WIMP annihilations. We demonstrate that the CMB data can give the stringent bounds on the allowed PBH fraction which are comparable or even tighter than those from the gamma ray data depending on the DM masses. For instance, the MCMC likelihood analysis using the Planck CMB data leads to the bound on PBH DM fraction with respect to the total dark matter $f_{\mathrm{PBH}}\lesssim \mathcal{O}(10^{-10}\sim 10^{-8})$ for the WIMP mass $m_{\chi }\sim \mathcal{O}(10\sim 10^3)$ GeV with the conventional DM annihilation cross section $⟨\sigma v⟩=3\times 10^{-26}\mathrm{c}{\mathrm{m}}^3/s$. We also investigate the feasibility of the global 21-cm signal measurement to provide the stringent constraints on the PBH fraction.

    ↳ astro-ph.COgr-qchep-phPRD(2021)·32 citations
14. 14*

    Improved $V_{cs}$ determination using precise lattice QCD form factors for $D\to K\ell \nu$

    Bipasha Chakraborty🇬🇧 · W. G. Parrott🇬🇧 · C. Bouchard🇬🇧 · C. T. H. Davies🇬🇧 · J. Koponen🇩🇪 · G. P. Lepage🇺🇸

    We provide a 0.8\%-accurate determination of $V_{cs}$ from combining experimental results for the differential rate of $D\to K$ semileptonic decays with precise form factors that we determine from lattice QCD. This is the first time that $V_{cs}$ has been determined with an accuracy that allows its difference from 1 to be seen. Our lattice QCD calculation uses the Highly Improved Staggered Quark (HISQ) action for all valence quarks on gluon field configurations generated by the MILC collaboration that include the effect of $u$, $d$, $s$ and $c$ HISQ quarks in the sea. We use eight gluon field ensembles with five values of the lattice spacing ranging from 0.15 fm to 0.045 fm and include results with physical $u/d$ quarks for the first time. Our calculated form factors cover the full $q^2$ range of the physical decay process and enable a Standard Model test of the shape of the differential decay rate as well as the determination of $V_{cs}$ from a correlated weighted average over $q^2$ bins. We obtain $|V_{cs}|=0.9663(53{)}_{\text{latt}}(39{)}_{\text{exp}}(19{)}_{{\eta }_{EW}}(40{)}_{\text{EM}}$, where the uncertainties come from lattice QCD, experiment, short-distance electroweak and electromagnetic corrections, respectively. This last uncertainty, neglected for $D\to K\ell \nu$ hitherto, now needs attention if the uncertainty on $V_{cs}$ is to be reduced further. We also determine $V_{cs}$ values in good agreement using the measured total branching fraction and the rates extrapolated to $q^2=0$. Our form factors enable tests of lepton flavour universality violation. We find the ratio of branching fractions for $D^0\to K^{-}$ with $\mu$ and $e$ in the final state to be $R_{\mu /e}=0.9779(2{)}_{\text{latt}}(50{)}_{\mathrm{EM}}$ in the Standard Model, with the uncertainty dominated by that from electromagnetic corrections.

    ↳ hep-lathep-phPRD(2021)·46 citations
15. 15*

    Prospects for the measurement of the $b$-quark mass at the ILC

    Juan Fuster (1)🇪🇸 · Adrian Irles (1)🇪🇸 · German Rodrigo (1)🇪🇸 · Seidai Tairafune (2)🇯🇵 · Marcel Vos (1)🇪🇸 · Hitoshi Yamamoto (1)🇪🇸 · Ryo Yonamine (2) ((1) IFIC, CSIC and Universitat de València, Spain, (2) Tohoku University Japan)🇯🇵

    This note presents an analysis of the potential of future high-energy electron-positron colliders to measure the $b$-quark mass. We perform a full-simulation study of the measurement of the ratio of the three-jet rates in events with $b\bar{b}(g)$ and $q\bar{q}(g)$ production, $R_3^{bl}$, and assess the dominant uncertainties, including theory and experimental systematic uncertainties. We find that the ILC "Higgs factory" stage, with an integrated luminosity of 2 ab${}^{-1}$ at $\sqrt{s}=$ 250 GeV can measure the $b-$quark $barMS$ mass at a scale of 250 GeV ($m_b(250$GeV$)$) with a precision of 1 GeV. From this result we extrapolate the potential of the GigaZ run running at $\sqrt{s}=m_Z$. We expect $m_b(m_Z)$ can be determined with an 0.12 GeV uncertainty, exceeding the precision of the LEP and SLD measurements by a factor $\sim$3.

    ↳ hep-exhep-ph11 citations
16. 16*

    Static magnetic susceptibility in finite-density SU(2) lattice gauge theory

    P. V. Buividovich🇬🇧 · D. Smith🇩🇪 · L. von Smekal🇩🇪

    We study static magnetic susceptibility $\chi (T,\mu )$ in $SU(2)$ lattice gauge theory with $N_f=2$ light flavours of dynamical fermions at finite chemical potential $\mu$. Using linear response theory we find that $SU(2)$ gauge theory exhibits paramagnetic behavior in both the high-temperature deconfined regime and the low-temperature confining regime. Paramagnetic response becomes stronger at higher temperatures and larger values of the chemical potential. For our range of temperatures $0.727\le T/T_c\le 2.67$, the first coefficient of the expansion of $\chi (T,\mu )$ in even powers of $\mu /T$ around $\mu =0$ is close to that of free quarks and lies in the range $(2\dots 5)\cdot 10^{-3}$. The strongest paramagnetic response is found in the diquark condensation phase at $\mu >m_{\pi }/2$.

    ↳ hep-lathep-phhep-thEPJA(2021)·23 citations
17. 17*

    $S$-matrix approach to general gravity and beyond

    Pierre Vanhove🇫🇷

    In this text we outline the motivation for developping a quantum $S$-matrix approach for the classical gravitational two-body scattering. As an application we briefly present the derivation of black-hole metrics in various dimensions.

    ↳ gr-qchep-phhep-th6 citations
18. 18*

    Options for a finite group model of quantum mechanics

    Robert A. Wilson🇬🇧

    There are four finite groups that could plausibly play the role of the spin group in a finite or discrete model of quantum mechanics, namely the four double covers of the three rotation groups of the Platonic solids. In an earlier paper I have considered in detail how the smallest of these groups, namely the binary tetrahedral group, of order 24, could give rise to a non-relativistic theory that contains much of the structure of the standard model of particle physics. In this paper I consider how one of the two double covers of the rotation group of the cube might extend this to a relativistic theory.

    ↳ math.GRhep-ph7 citations
19. 19*

    Radioactive background for ProtoDUNE detector

    Mihaela Parvu🇷🇴 · Ionel Lazanu🇷🇴

    The Deep Underground Neutrino Experiment (DUNE) is a leading-edge, international experiment for neutrino science and proton decay studies. This experiment is looking for answers regarding several fundamental questions about the nature of matter and the evolution of the universe: origin of matter, unification of forces, physics of black holes. Two far detector prototypes using two distinct technologies have been developed at CERN. The prototypes are testing and validating the liquid argon time projection chamber technology (LArTPC). In neutrino physics, as well as in any experiment with rare interaction rate, the good knowledge of the radioactive backgrounds is important to the success of the study. Unlike most of the charged particles or short lived neutral particles, muons and neutrons represent the main sources of background for this kind of experiments. In this paper, we have considered two sources of neutrons: cosmic neutrons and neutrons coming from the accelerating tunnel. Also, cosmic muons are taken into account. The contribution of these particles to the production of radioactive isotopes inside the active volume of the detector in comparison to the one corresponding to muons is shown. Also, simulations of nuclear reactions for the processes of interest for investigating the radioactive background due to the lack of measurements or insufficient experimental data are presented. The results presented are of interest for the future underground DUNE experiment.

    ↳ physics.ins-dethep-exhep-phJCAP(2021)·4 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.