Thu·Jan 14, 2021Thursday·January 14, 2021

1. 01*

   Local one-dimensional reggeon model of the interaction of pomerons and odderons

   M.A. Braun🇷🇺 · E.M. Kuzminskii🇷🇺 · M.I. Vyazovsky (Saint-Petersburg State University, Russia)🇷🇺

   We propose the one-dimensional reggeon theory describing local pomerons and odderons. It generalizes the well-known one-dimensional theory of pomerons (the Gribov model) and includes only triple interaction vertices. The proposed theory is studied by numerical methods: the one-particle pomeron and odderon propagators and the pA amplitude are found as functions of rapidity by integrating the evolution equation.

   hep-phEPJC(2021)·5 citations
2. 02*

   Laplace's method for elastic scattering diagrams within multi-particle fields model

   N.O. Chudak🇺🇦 · I.V. Sharph🇺🇦 · O.S. Potiienko🇺🇦 · K.K. Merkotan🇺🇦 · T.V. Yushkevych🇺🇦 · A.O. Milieva🇺🇦 · V.D. Rusov🇺🇦

   We apply the multi-particle fields model to calculate the differential cross-section d{\sigma}/dt of elastic proton-proton scattering. This problem includes the calculation of multidimensional integrals arising from the loop Feynman diagrams. We demonstrated how these integrals can be reduced with Laplace's method to one- and two-dimensional integrals which can be calculated numerically. The obtained result qualitatively describe the minimum in differential cross-section dependency d{\sigma}/dt(t).

   hep-phPRD(2022)·1 citation
3. 03*

   Analyticity, renormalization, and evolution of the soft-quark function

   Geoffrey T. Bodwin🇺🇸 · June-Haak Ee🇰🇷 · Jungil Lee🇰🇷 · Xiang-Peng Wang🇺🇸

   We compute the renormalization and evolution of the soft-quark function that appears in the factorization theorem for Higgs-boson decays to two photons through a $b$-quark loop. Our computation confirms a conjecture by Liu, Mecaj, Neubert, Wang, and Fleming for the form of the renormalization and evolution of the soft-quark function in order ${\alpha }_s$. We also work out the analyticity structure of the soft-quark function by making use of light-cone perturbation theory.

   hep-phPRD(2021)·13 citations
4. 04*

   Probing a degenerate-scalar scenario in a pseudoscalar dark-matter model

   Sachiho Abe🇯🇵 · Gi-Chol Cho🇯🇵 · Kentarou Mawatari🇯🇵

   We study a pseudoscalar dark-matter model arising from a complex singlet extension of the standard model (SM), and show that the dark-matter--nucleon scattering is suppressed when two CP-even scalars are degenerate. In such a degenerate-scalar scenario we explore the model parameter space which satisfies constraints from the direct detection experiments and the relic density of dark matter. In addition, we discuss a possibility to verify such a scenario by using the recoil mass technique at the International Linear Collider. We find that a pair of states separated by 0.2 GeV can be distinguished from the single SM-like Higgs state at 5$\sigma$ with integrated luminosity of 2 ab${}^{-1}$.

   hep-phPRD(2021)·29 citations
5. 05*

   The $\mathbf{sQ}\bar{\mathbf{q}}\bar{\mathbf{q}}$ $(\mathbf{q}=\mathbf{u},\mathbf{d};\mathbf{Q}=\mathbf{c},\mathbf{b})$ tetraquarks in the chiral quark model

   Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

   The low-lying $sQ\bar{q}\bar{q}$ $(q=u,d,Q=c,b)$ tetraquark states with $J^P=0^{+}$, $1^{+}$ and $2^{+}$, and in the isoscalar and isovector sectors, are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron and multiquark phenomenology, and thus all results presented here are pure predictions. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account; this includes meson-meson, diquark-antidiquark and K-type arrangements of quarks with all possible color wave functions in four-body sector. Among the different numerical techniques to solve the Schrödinger-like 4-body bound state equation, we use a variational method in which the trial wave function is expanded in complex-range Gaussian basis functions, because its simplicity and flexibility. Several compact bound states and narrow resonances are found in both charm-strange $cs\bar{q}\bar{q}$ and bottom-strange $bs\bar{q}\bar{q}$ tetraquark sectors, most of them as a product of the strong coupling between the different channels. The so-called $X_{0,1}(2900)$ signals, recently found by the LHCb collaboration, are unstable in our formalism with several candidates in the single-channel computations.

   hep-phhep-exhep-latnucl-ex+1PRD(2021)·41 citations
6. 06*

   Gauged $L_{\mu }^{}-L_{\tau }^{}$ at a muon collider

   Guo-yuan Huang🇩🇪 · Farinaldo S. Queiroz🇧🇷 · Werner Rodejohann🇩🇪

   We investigate the sensitivity of the projected TeV muon collider to the gauged $L_{\mu }^{}$-$L_{\tau }^{}$ model. Two processes are considered: $Z^{\prime }$-mediated two-body scatterings ${\mu }^{+}{\mu }^{-}\to {\ell }^{+}{\ell }^{-}$ with $\ell =\mu$ or $\tau$, and scattering with initial state photon emission, ${\mu }^{+}{\mu }^{-}\to \gamma Z^{\prime },Z^{\prime }\to \ell \overline{\ell }$, where $\ell$ can be $\mu$, $\tau$ or ${\nu }_{\mu /\tau }$. We quantitatively study the sensitivities of these two processes by taking into account possible signals and relevant backgrounds in a muon collider experiment with a center-of-mass energy $\sqrt{s}=3\mathrm{TeV}$ and a luminosity $L=1\mathrm{a}{\mathrm{b}}^{-1}$. For two-body scattering one can exclude $Z^{\prime }$ masses $M_{Z^{\prime }}^{}\lesssim 100\mathrm{TeV}$ with $\mathcal{O}(1)$ gauge couplings. When $M_{Z^{\prime }}^{}\lesssim 1\mathrm{TeV}<\sqrt{s}$, one can exclude $g^{\prime }\gtrsim 2\times 10^{-2}$. The process with photon emission is more powerful than the two-body scattering if $M_{Z^{\prime }}^{}<\sqrt{s}$. For instance, a sensitivity of $g^{\prime }\simeq 4\times 10^{-3}$ can be achieved at $M_{Z^{\prime }}^{}=1\mathrm{TeV}$. The parameter spaces favored by the $(g-2{)}_{\mu }^{}$ and $B$ anomalies with $M_{Z^{\prime }}^{}>100\mathrm{GeV}$ are entirely covered by a muon collider.

   hep-phhep-exPRD(2021)·111 citations
7. 07*

   Exact Oscillation Probabilities of Neutrinos in Three generations derived from Relativistic Equation

   Keiichi Kimura🇯🇵 · Akira Takamura🇯🇵

   In three generations or more, we derive the oscillation probabilities of both Dirac and Majorana neutrinos relativistically by using the Dirac equation. We present various oscillation probabilities for including wrong-helicity neutrinos, right-handed neutrinos, and anti-neutrinos. We summarize the relations between these probabilities. As neutrinos have finite mass, there are two components for each chirality corresponding to positive and negative helicities. We show that the probability is different for each component even if neutrinos have the same chirality. The probabilities derived by the relativistic equation depend on not only the mass squared differences but also the absolute masses of neutrinos. Besides, the new CP phases appear in the probabilities of oscillations with chirality-flip. These new CP phases are equivalent to the Majorana CP phases in the case of Majorana neutrinos. We investigate the CP dependence of oscillation probabilities in vacuum. There are no direct CP violation in ${\nu }_{\alpha }\leftrightarrow {\nu }_{\beta }^c$ oscillations even if the flavors, $\alpha$ and $\beta$, are different as in the same as two generations. In other words, the difference between the CP-conjugate probabilities vanishes. However, in three generations or more, the sine terms of new CP phases appear in the probabilities in addition to the cosine terms. This is different from the result obtained in two generations. Furthermore, the zero-distance effect does not appear in our formulation.

   hep-ph2 citations
8. 08*

   Electric charge renormalization to all orders

   Stefan Dittmaier🇩🇪

   The electric charge renormalization constant, as defined in the Thomson limit, is expressed in terms of self-energies of the photon-Z-boson system in an arbitrary R_\xi-gauge to all perturbative orders. The derivation as carried out in the Standard Model holds in all spontaneously broken gauge theories with the SU(2)_w \times U(1)_Y gauge group in the electroweak sector and is based on the application of charge universality to a fake fermion with infinitesimal weak hypercharge and vanishing weak isospin, which effectively decouples from all other particles. Charge universality, for instance, follows from the known universal form of the charge renormalization constant as derived within the background-field formalism. Finally, we have generalized the described procedure to gauge theories with gauge group U(1)_Y \times G with any Lie group G, only assuming that electromagnetic gauge symmetry is unbroken and mixes with U(1)_Y transformations in a non-trivial way.

   hep-phPRD(2021)·12 citations
9. 09*

   Axion assisted Schwinger effect

   Valerie Domcke🇨🇭 · Yohei Ema🇩🇪 · Kyohei Mukaida🇨🇭

   We point out an enhancement of the pair production rate of charged fermions in a strong electric field in the presence of time dependent classical axion-like background field, which we call axion assisted Schwinger effect. While the standard Schwinger production rate is proportional to $\exp (-\pi (m^2+p_T^2)/E)$, with $m$ and $p_T$ denoting the fermion mass and its momentum transverse to the electric field $E$, the axion assisted Schwinger effect can be enhanced at large momenta to $\exp (-\pi m^2/E)$. The origin of this enhancement is a coupling between the fermion spin and its momentum, induced by the axion velocity. As a non-trivial validation of our result, we show its invariance under field redefinitions associated with a chiral rotation and successfully reproduce the chiral anomaly equation in the presence of helical electric and magnetic fields. We comment on implications of this result for axion cosmology, focussing on axion inflation and axion dark matter detection.

   hep-phastro-ph.COcond-mat.mes-hallhep-thJHEP(2021)·31 citations
10. 10*

    Novel twist-three transverse-spin sum rule for the proton and related generalized parton distributions

    Yuxun Guo🇺🇸 · Xiangdong Ji🇺🇸 · Kyle Shiells🇺🇸

    We derive a new twist-3 partonic sum rule for the transverse spin of the proton, which involves the well-know quark spin structure function $g_T(x)=g_1(x)+g_2(x)$, the less-studied but known transverse gluon polarization density $\Delta G_T(x)$, and quark and gluon canonical orbital angular momentum densities associated with transverse polarization. This is the counter part of the sum rule for the longitudinal spin of the proton derived by Jaffe and Manohar previously. We relate the partonic canonical orbital angular momentum densities to a new class of twist-3 generalized parton distribution functions which are potentially measurable in deep-virtual exclusive processes. We also discuss in detail an important technicality related to the transverse polarization in the infinite momentum frame, i.e., separation of intrinsic contributions from the extrinsic ones. We apply our finding to the transverse-space distributions of partons, angular momentum, and magnetic moment, respectively, in a transversely polarized proton.

    hep-phhep-latnucl-exnucl-thNPB(2021)·36 citations
11. 11*

    New flavor physics in di- and tri-lepton events from single-top at the LHC and beyond

    Yoav Afik🇮🇱 · Shaouly Bar-Shalom🇮🇱 · Amarjit Soni🇺🇸 · Jose Wudka🇺🇸

    The associated production of a single-top with opposite-sign same-flavor (OSSF) di-leptons, $pp\to t{\ell }^{+}{\ell }^{-}$ and $pp\to t{\ell }^{+}{\ell }^{-}+j$ ($j=$light jet), can lead to striking tri-lepton $pp\to {\ell }^{\prime }{\ell }^{+}{\ell }^{-}+X$ and di-lepton $pp\to {\ell }^{+}{\ell }^{-}+j_b+X$ ($j_b=b$-jet) events at the LHC, after the top decays. Although these rather generic multi-lepton signals are flavor-blind, they can be generated by new 4-Fermi flavor changing (FC) $u_{i}t\ell \ell$ scalar, vector and tensor interactions ($u_i\in u,c$), which we study in this paper; we match the FC $u_{i}t\ell \ell$ 4-Fermi terms to the SMEFT operators and also to different types of FC underlying heavy physics. The main backgrounds to these di- and tri-lepton signals arise from $t\bar{t}$, $Z$+jets and $VV$ ($V=W,Z$) production, but they can be essentially eliminated with a sufficiently high invariant mass selection on the OSSF di-leptons, $m_{{\ell }^{+}{\ell }^{-}}^{\mathtt{min}}(OSSF)>1$ TeV; the use of $b$-tagging as an additional selection in the di-lepton final state case also proves very useful. We find, for example, that the expected 95\% CL bounds on the scale of a tensor(vector) $ut\mu \mu$ interaction, with the current $\sim 140$ fb${}^{-1}$ of LHC data, are $\Lambda <5(3.2)$ TeV or $\Lambda <4.1(2.7)$ TeV, if analyzed via the di-muon ${\mu }^{+}{\mu }^{-}+j_b$ signal or the $e{\mu }^{+}{\mu }^{-}$ tri-lepton one, respectively. The expected reach at the HL-LHC with 3000 fb${}^{-1}$ of data is $\Lambda <7.1(4.7)$ TeV and $\Lambda <2.4(1.5)$ TeV for the corresponding $ut\mu \mu$ and $ct\mu \mu$ operators. We also study the potential sensitivity at future 27 TeV and 100 TeV high-energy LHC successors and also discuss the possible implications of this class of FC 4-Fermi effective interactions on lepton non-universality tests at the LHC.

    hep-phhep-exPRD(2021)·21 citations
12. 12*

    Hydrodynamics of spin currents

    Domingo Gallegos🇳🇱 · Umut Gursoy🇳🇱 · Amos Yarom🇮🇱

    We study relativistic hydrodynamics in the presence of a non vanishing spin chemical potential. Using a variety of techniques we carry out an exhaustive analysis, and identify the constitutive relations for the stress tensor and spin current in such a setup, allowing us to write the hydrodynamic equations of motion to second order in derivatives. We then solve the equations of motion in a perturbative setup and find surprisingly good agreement with measurements of global $\Lambda$-hyperon polarization carried out at RHIC.

    ↳ hep-thhep-phnucl-thSciPost Phys.(2021)·155 citations
13. 13*

    Lattice determinations of the strong coupling

    Luigi Del Debbio🇬🇧 · Alberto Ramos🇮🇪

    Lattice QCD has reached a mature status. State of the art lattice computations include $u,d,s$ (and even the $c$) sea quark effects, together with an estimate of electromagnetic and isospin breaking corrections for hadronic observables. This precise and first principles description of the standard model at low energies allows the determination of multiple quantities that are essential inputs for phenomenology and not accessible to perturbation theory. One of the fundamental parameters that are determined from simulations of lattice QCD is the strong coupling constant, which plays a central role in the quest for precision at the LHC. Lattice calculations currently provide its best determinations, and will play a central role in future phenomenological studies. For this reason we believe that it is timely to provide a pedagogical introduction to the lattice determinations of the strong coupling. Rather than analysing individual studies, the emphasis will be on the methodologies and the systematic errors that arise in these determinations. We hope that these notes will help lattice practitioners, and QCD phenomenologists at large, by providing a self-contained introduction to the methodology and the possible sources of systematic error. The limiting factors in the determination of the strong coupling turn out to be different from the ones that limit other lattice precision observables. We hope to collect enough information here to allow the reader to appreciate the challenges that arise in order to improve further our knowledge of a quantity that is crucial for LHC phenomenology.

    ↳ hep-lathep-phPhys.Rept.(2021)·38 citations
14. 14*

    Stringent constraint on the radio signal from dark matter annihilation in dwarf spheroidal galaxies using the TGSS

    Arghyadeep Basu🇮🇳 · Nirupam Roy🇨🇦 · Samir Choudhuri🇬🇧 · Kanan K. Datta🇮🇳 · Debajyoti Sarkar🇮🇳

    Weakly Interacting Massive Particles (WIMPs) are considered to be one of the favoured dark matter candidates. Searching for any detectable signal due to the annihilation and decay of WIMPs over the entire electromagnetic spectrum has become a matter of interest for the last few decades. WIMP annihilation to Standard Model particles gives rise to a possibility of detection of this signal at low radio frequencies via synchrotron radiation. Dwarf Spheroidal Galaxies (dSphs) are expected to contain a huge amount of dark matter which makes them promising targets to search for such large scale diffuse radio emission. In this work, we present a stacking analysis of 23 dSph galaxies observed at low frequency (147.5MHz) as part of the TIFR-GMRT Sky Survey (TGSS). The non-detection of any signal from these stacking exercises put very tight constraints on the dark matter parameters. The best limit comes from the novel method of stacking after scaling the radio images of the individual dSph galaxy fields after scaling them by the respective half-light radius. The constraint on the thermally averaged cross-section is below the thermal relic cross-section value over a range of WIMP mass for reasonable choices of relevant astrophysical parameters. Such analysis using future deeper observation of individual targets as well as stacking can potentially reveal more about the WIMP dark matter properties.

    ↳ astro-ph.HEastro-ph.GAhep-phMNRAS(2021)·16 citations
15. 15*

    A Demonstration of Hadron Mass Origin from QCD Trace Anomaly

    Fangcheng He🇨🇳 · Peng Sun🇨🇳 · Yi-Bo Yang🇨🇳

    Quantum chromodynamics (QCD) claims that the major source of the nucleon invariant mass is not the Higgs mechanism but the trace anomaly in QCD energy momentum tensor. Although experimental and theoretical results support such conclusion, a direct demonstration is still absent. We present the first Lattice QCD calculation of the quark and gluon trace anomaly contributions to the hadron masses, using the overlap fermion on the 2+1 flavor dynamical Domain wall quark ensemble at $m_{\pi }=340$ MeV and lattice spacing $a=$0.1105 fm. The result shows that the gluon trace anomaly contributes to most of the nucleon mass, and the contribution in the pion state is smaller than that in others nearly by a factor $\sim$10 since the gluon trace anomaly density inside pion is different from the other hadrons and the magnitude is much smaller. The gluon trace anomaly coefficient $\beta /g^3=-0.056(6)$ we obtained is consistent with its regularization independent leading order value $(-11+\frac{2N_f}{3})/(4\pi {)}^2$ perfectly.

    ↳ hep-lathep-phnucl-thPRD(2021)·25 citations
16. 16*

    Angular Momentum and the Absence of Vortices in the Cores of Fuzzy Dark Matter Haloes

    Sonja O. Schobesberger🇦🇹 · Tanja Rindler-Daller🇦🇹 · Paul R. Shapiro🇺🇸

    Scalar Field Dark Matter (SFDM), comprised of ultralight ($\gtrsim 10^{-22}$ eV) bosons, is distinguished from massive ($\gtrsim$ GeV), collisionless Cold Dark Matter (CDM) by its novel structure-formation dynamics as Bose-Einstein condensate (BEC) and quantum superfluid with wave-like properties, described by the Gross-Pitaevski and Poisson (GPP) equations. In the free-field (fuzzy) limit of SFDM (FDM), structure is inhibited below the de Broglie wavelength ${\lambda }_{\text{deB}}$, but resembles CDM on larger scales. Virialized haloes have solitonic cores of radius $\sim {\lambda }_{\text{deB}}$ that follow the ground-state attractor solution of GPP, surrounded by CDM-like envelopes. As superfluid, SFDM is irrotational (vorticity-free) but can be unstable to vortex formation. We previously showed this can happen in halo cores, from angular momentum arising during structure formation, when repulsive self-interaction (SI) is present to support them out to a second length scale ${\lambda }_{\text{SI}}$ with ${\lambda }_{\text{SI}}>{\lambda }_{\text{deB}}$ (the Thomas-Fermi regime), but only if SI is strong enough. This suggested FDM cores (without SI) would not form vortices. FDM simulations later found vortices, but only outside halo cores, consistent with our previous suggestion based upon TF-regime analysis. We extend that analysis now to FDM, to show explicitly that vortices should not arise in solitonic cores from angular momentum, modelling them as either Gaussian spheres or compressible, ($n=2$)-polytropic, irrotational Riemann-S ellipsoids. We find that, for typical halo spin parameters, angular momentum per particle is below $\hslash$, the minimum required even for one singly-quantized vortex in the centre. Even for larger angular momentum, however, vortex formation is not energetically favoured.

    ↳ astro-ph.GAastro-ph.COcond-mat.quant-gashep-phMNRAS(2021)·20 citations
17. 17*

    Testing wormhole solutions in extended gravity through the Poynting-Robertson effect

    Vittorio De Falco🇮🇹 · Emmanuele Battista🇩🇪 · Salvatore Capozziello🇮🇹 · Mariafelicia De Laurentis🇮🇹

    We develop a model-independent procedure to single out static and spherically symmetric wormhole solutions based on the general relativistic Poynting-Robertson effect and the extension of the ray-tracing formalism in generic static and spherically symmetric wormhole metrics. Simulating the flux emitted by the Poynting-Robertson critical hypersurface (i.e., a stable structure where gravitational and radiation forces attain equilibrium) or also from another X-ray source in these general geometrical environments toward a distant observer, we are able to reconstruct, only locally to the emission region, the wormhole solutions which are in agreement with the high-energy astrophysical observational data. This machinery works only if wormhole evidences have been detected. Indeed, in our previous paper we showed how the Poynting-Robertson critical hypersurfaces can be located in regions of strong gravitational field and become valuable astrophysical probe to observationally search for wormholes' existence. As examples, we apply our method to selected wormhole solutions in different extended theories of gravity by producing lightcurves, spectra, and images of an accretion disk. In addition, the present approach may constitute a procedure to also test the theories of gravity. Finally, we discuss the obtained results and draw the conclusions.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2021)·132 citations
18. 18*

    No black holes from cosmic string cusps

    Jose J. Blanco-Pillado🇪🇸 · Ken D. Olum🇺🇸 · Alexander Vilenkin🇺🇸

    Recent work by Jenkins and Sakellariadou claims that cusps on cosmic strings lead to black hole production. To derive this conclusion they use the hoop conjecture in the rest frame of the string loop, rather than in the rest frame of the proposed black hole. Most of the energy they include is the bulk motion of the string near the cusp. We redo the analysis taking this into account and find that cusps on cosmic strings with realistic energy scale do not produce black holes, unless the cusp parameters are extremely fine-tuned.

    ↳ astro-ph.COgr-qchep-ph14 citations
19. 19*

    Resolving spacetime singularities in flux compactifications & KKLT

    Federico Carta🇬🇧 · Jakob Moritz🇺🇸

    In flux compactifications of type IIB string theory with D3 and seven-branes, the negative induced D3 charge localized on seven-branes leads to an apparently pathological profile of the metric sufficiently close to the source. With the volume modulus stabilized in a KKLT de Sitter vacuum this pathological region takes over a significant part of the entire compactification, threatening to spoil the KKLT effective field theory. In this paper we employ the Seiberg-Witten solution of pure $SU(N)$ super Yang-Mills theory to argue that wrapped seven-branes can be thought of as bound states of more microscopic exotic branes. We argue that the low-energy worldvolume dynamics of a stack of $n$ such exotic branes is given by the $(A_1,A_{n-1})$ Argyres-Douglas theory. Moreover, the splitting of the perturbative (in ${\alpha }^{\prime }$) seven-brane into its constituent branes at the non-perturbative level resolves the apparently pathological region close to the seven-brane and replaces it with a region of $\mathcal{O}(1)$ Einstein frame volume. While this region generically takes up an $\mathcal{O}(1)$ fraction of the compactification in a KKLT de Sitter vacuum we argue that a small flux superpotential \textit{dynamically} ensures that the 4d effective field theory of KKLT remains valid nevertheless.

    ↳ hep-thhep-phJHEP(2021)·37 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.