Mon·Jul 29, 2019Monday·July 29, 2019

1. 01*

   Higgs Assisted Razor Search for Higgsinos at a 100 TeV pp Collider

   Adarsh Pyarelal🇺🇸 · Shufang Su🇺🇸

   A 100 TeV proton-proton collider will be an extremely effective way to probe the electroweak sector of the Minimal Supersymmetric Standard Model (MSSM). In this paper, we describe a search strategy for discovering pair-produced Higgsino-like next-to-lightest supersymmetric particles (NLSPs) at a 100 TeV hadron collider that decay to Bino-like lightest supersymmetric particle (LSP) via intermediate Z and SM Higgs boson that in turn decay to a pair of leptons and a pair of b-quarks respectively: ${\tilde{N}}_2^0{\tilde{N}}_3^0\to (Z{\tilde{N}}_1^0)(h{\tilde{N}}_1^0)\to bb\ell \ell +{\tilde{N}}_1^0{\tilde{N}}_1^0$. In addition, we examine the potential for machine learning techniques to boost the power of our searches. Using this analysis, Higgsinos up to 1.4 TeV can be discovered at $5\sigma$ level for a Bino with mass of about 0.9 TeV using 3000 fb${}^{-1}$ of data. Additionally, Higgsinos up to 1.8 TeV can be excluded at 95% C.L. for Binos with mass of about 1.4 TeV. This search channel extends the multi-lepton search limits, especially in the region where the mass difference between the Higgsino NLSPs and the Bino LSP is small.

   hep-phSCPMA(2020)·2 citations
2. 02*

   Lepton angular distributions of Drell-Yan process in pQCD and a geometric approach

   Wen-Chen Chang🇹🇼 · Randall Evan McClellan🇺🇸 · Jen-Chieh Peng🇺🇸 · Oleg Teryaev🇷🇺

   The lepton angular distributions of the Drell-Yan process in the fixed-target experiments are investigated by NLO and NNLO perturbative QCD. We present the calculated angular parameters $\lambda$, $\mu$, $\nu$ and the degree of violation of the Lam-Tung relation, $1-\lambda -2\nu$, for the E615 experiment as well as predictions for the COMPASS experiment. Many salient features of transverse momentum and rapidity dependence could be qualitatively understood by a geometric approach.

   hep-phnucl-exnucl-thPoS(2019)·1 citation
3. 03*

   Oscillating Composite Asymmetric Dark Matter

   Masahiro Ibe🇯🇵 · Shin Kobayashi🇯🇵 · Ryo Nagai🇯🇵 · Wakutaka Nakano🇯🇵

   The asymmetric dark matter (ADM) scenario can solve the coincidence problem between the baryon and the dark matter (DM) abundance when the DM mass is of $\mathcal{O}(1)$GeV. In the ADM scenarios, composite dark matter is particularly motivated, as it can naturally provide the DM mass in the $\mathcal{O}(1)$GeV range and a large annihilation cross section simultaneously. In this paper, we discuss the indirect detection constraints on the composite ADM model. The portal operators connecting the $B-L$ asymmetries in the dark and the Standard Model(SM) sectors are assumed to be generated in association with the seesaw mechanism. In this model, composite dark matter inevitably obtains a tiny Majorana mass which induces a pair-annihilation of ADM at late times. We show that the model can be efficiently tested by the searches for the $\gamma$-ray from the dwarf spheroidal galaxies and the interstellar electron/positron flux.

   hep-phastro-ph.HEJHEP(2020)·10 citations
4. 04*

   Thermodynamics and susceptibilities of isospin imbalanced QCD matter

   Zhen-Yan Lu🇨🇳 · Cheng-Jun Xia🇨🇳 · Marco Ruggieri🇨🇳

   We study the thermodynamics and the susceptibilities of quark matter in the framework of two-flavor Nambu-Jona-Lasinio model at finite isospin chemical potential and temperature. Isospin number density, normalized energy density and trace anomaly are shown to be in good agreement with the available lattice data as well as with the results from chiral perturbation theory at zero temperature. We also study how susceptibilities depend on the isospin chemical potential and on temperature. We find a peak for the chiral, pion, and isospin susceptibilities at the critical isospin chemical potential, ${\mu }_I^c(T)$, at the boundary of the phase transition between the normal and pion superfluid phase. Moreover, temperature makes the transition from normal to pion condended phase smoother. We also note that the pion susceptibility always remains zero in the normal phase while it is finite in the superfluid phase.

   hep-phEPJC(2020)·38 citations
5. 05*

   Radiative neutrino model with semi-annihilation dark matter

   Haiying Cai🇰🇷

   We propose a Two-Loop induced radiative neutrino model with hidden gauged $U(1)$ symmetry, in which a dark matter of Dirac fermion arises. The relic density gets contribution from annihilation and semi-annihilation due to a residual ${\mathbb{Z}}_3$ parity. After imposing the requirement of neutrino oscillation data and lepton flavour violation bounds, we find out that the semi-annihilation plays a crucial role in order to satisfy the relic density constraint $0.117<\Omega h^2<0.123$, by proceeding near either one of two deconstructive scalar resonances. Our numerical analysis demonstrates the allowed region for the DM-Scalar coupling with the DM mass in $(80,400)$ GeV.

   hep-phPRD(2020)·1 citation
6. 06*

   Simple operator formulation of the Bakamjian-Thomas approach to heavy quark current , with generalisation to HQET, and with applications to transitions of Lambda-b

   Damir Becirevic🇫🇷 · Vincent Morenas🇫🇷 · Alain Le-Yaouanc🇫🇷 · Luis Oliver🇫🇷

   Starting from the general formulation of current matrix elements in the Bakamjian-Thomas (BT) approach to quark models, certain aspects of their heavy quark limit are exhibited in an intuitive form, allowing a common treatment for any number of quarks and angular momenta j,j'. We use the general Falk interpretation of Isgur-Wise functions as overlaps of light parton states in motion. Then, in BT, for small collinear velocities, the motion of these states is described by a very simple dimensionless differential operator O acting on the internal wave functions of the light quarks, which is a relativistic generalisation of the dipole operator times the quark mass : it appears as the generator of Lorentz transformations for N free light particles.

   hep-ph3 citations
7. 07*

   Confronting the coloured sector of the MRSSM with LHC data

   Philip Diessner🇩🇪 · Jan Kalinowski🇵🇱 · Wojciech Kotlarski🇩🇪 · Dominik Stöckinger🇩🇪

   R-symmetry leads to a distinct low energy realisation of SUSY with a significantly modified colour-charged sector featuring a Dirac gluino and scalar colour octets (sgluons). In the present work we recast results from LHC BSM searches to discuss the impact of R-symmetry on the squark and gluino mass limits. We work in the framework of the Minimal R-symmetric Supersymmetric Standard Model and take into account the NLO corrections to the squark production cross sections in the MRSSM that have become available recently. We find substantially weaker limits on squark masses compared to the MSSM: for simple scenarios with heavy gluinos and degenerate squarks, the MRSSM mass limit is $m_{\tilde{q}}>1.7$ TeV, approximately 600 GeV lower than in the MSSM.

   hep-phJHEP(2019)·19 citations
8. 08*

   COHERENT constraints after the COHERENT-2020 quenching factor measurement

   Dimitrios K. Papoulias🇪🇸

   Recently an improved quenching factor (QF) measurement for low-energy nuclear recoils in CsI[Na] has been reported by the COHERENT Collaboration. The new energy-dependent QF is characterized by a reduced systematic uncertainty and leads to a better agreement between the experimental COHERENT data and the Standard Model (SM) expectation. In this work, we report updated constraints on parameters that describe the process of coherent elastic neutrino-nucleus scattering within and beyond the SM, and we also present how the new QF affects their interpretation.

   hep-phPRD(2020)·66 citations
9. 09*

   Hidden Treasures: sterile neutrinos as dark matter with miraculous abundance, structure formation for different production mechanisms, and a solution to the sigma-8 problem

   Kevork N. Abazajian (UC Irvine)🇺🇸 · Alexander Kusenko (UCLA)🇺🇸

   We discuss numerous mechanisms for production of sterile neutrinos, which can account for all or a fraction of dark matter, and which can range from warm to effectively cold dark matter, depending on the cosmological scenario. We investigate production by Higgs boson decay, $(B-L)$ gauge boson production at high temperature, as well as production via resonant and nonresonant neutrino oscillations. We calculate the effects on structure formation in these models, some for the first time. If two populations of sterile neutrinos, one warm and one cold, were produced by different mechanisms, or if sterile neutrinos account for only a fraction of dark matter, while the remainder is some other cold dark matter particle, the resulting multi-component dark matter may alleviate some problems in galaxy formation. We examine the X-ray constraints and the candidate signal at 3.5 keV. Finally, we also show that the ${\sigma }_8$ problem can be a signature of fractional dark matter in the form of sterile neutrinos in several mechanisms.

   hep-phastro-ph.COPRD(2019)·38 citations
10. 10*

    Modular $A_4$ Symmetry Models of Neutrinos and Charged Leptons

    Gui-Jun Ding🇨🇳 · Stephen F. King🇬🇧 · Xiang-Gan Liu🇨🇳

    We present a comprehensive analysis of neutrino mass and lepton mixing in theories with $A_4$ modular symmetry, where the only flavon field is the single modulus field $\tau$, and all masses and Yukawa couplings are modular forms. Similar to previous analyses, we discuss all the simplest neutrino sectors arising from both the Weinberg operator and the type I seesaw mechanism, with lepton doublets and right-handed neutrinos assumed to be triplets of $A_4$. Unlike previous analyses, we allow right-handed charged leptons to transform as all combinations of $1$, $1^{\prime }$ and $1^{\prime \prime }$ representations of $A_4$, using the simplest different modular weights to break the degeneracy, leading to ten different charged lepton Yukawa matrices, instead of the usual one. This implies ten different Weinberg models and thirty different type I seesaw models, which we analyse in detail. We find that fourteen models for both NO and IO neutrino mass ordering can accommodate the data, as compared to one in previous analyses, providing many new possibilities.

    hep-phJHEP(2019)·175 citations
11. 11*

    A renormalized approach to neutrinoless double-beta decay

    V. Cirigliano🇺🇸 · W. Dekens🇺🇸 · J. de Vries🇺🇸 · M. L. Graesser🇺🇸 · E. Mereghetti🇺🇸 · S. Pastore🇺🇸 · M. Piarulli🇺🇸 · U. van Kolck🇫🇷 · R. B. Wiringa🇺🇸

    The process at the heart of neutrinoless double-beta decay, $nn\to pp{e}^{-}{e}^{-}$ induced by a light Majorana neutrino, is investigated in pionless and chiral effective field theory. We show in various regularization schemes the need to introduce a short-range lepton-number-violating operator at leading order, confirming earlier findings. We demonstrate that such a short-range operator is only needed in spin-singlet $S$-wave transitions, while leading-order transitions involving higher partial waves depend solely on long-range currents. Calculations are extended to include next-to-leading corrections in perturbation theory, where to this order no additional undetermined parameters appear. We establish a connection based on chiral symmetry between neutrinoless double-beta decay and nuclear charge-independence breaking induced by electromagnetism. Data on the latter confirm the need for a leading-order short-range operator, but do not allow for a full determination of the corresponding lepton-number-violating coupling. Using a crude estimate of this coupling, we perform ab initio calculations of the matrix elements for neutrinoless double-beta decay for ${}^6$He and ${}^{12}$Be. We speculate on the phenomenological impact of the leading short-range operator on the basis of these results.

    ↳ nucl-thhep-phPRC(2019)·141 citations
12. 12*

    Projected Proca Field Theory: a One-Loop Study

    R. F. Ozela🇳🇱 · Van Sérgio Alves🇧🇷 · E. C. Marino🇧🇷 · Leandro O. Nascimento🇧🇷 · J. F. Medeiros Neto🇧🇷 · Rudnei O. Ramos🇧🇷 · C. Morais Smith🇳🇱

    The recent discovery of two-dimensional Dirac materials, such as graphene and transition-metaldichalcogenides, has raised questions about the treatment of hybrid systems, in which electrons moving in a two-dimensional plane interact via virtual photons from the three-dimensional space. In this case, a projected non-local theory, known as Pseudo-QED, or reduced QED, has shown to provide a correct framework for describing the interactions displayed by these systems. In a related situation, in planar materials exhibiting a superconducting phase, the electromagnetic field has a typical exponential decay that is interpreted as the photons having an effective mass, as a consequence of the Anderson-Higgs mechanism. Here, we use an analogous projection to that used to obtain the pseudo-QED to derive a Pseudo-Proca equivalent model. In terms of this model, we unveil the main effects of attributing a mass to the photons and to the quasi-relativistic electrons. The one-loop radiative corrections to the electron mass, to the photon and to the electron-photon vertex are computed. We calculate the quantum corrections to the electron g-factor and show that it smoothly goes to zero in the limit when the photon mass is much larger than the electron mass. In addition, we correct the results obtained for graphene within Pseudo-QED in the limit when the photon mass vanishes.

    ↳ hep-thcond-mat.supr-conhep-ph6 citations
13. 13*

    Upsilon decay widths in magnetized asymmetric nuclear matter

    Amruta Mishra🇮🇳 · S.P. Misra🇮🇳

    The in-medium partial decay widths of ${\rm Y}(4S)\to B\bar{B}$ in magnetized asymmetric nuclear matter are studied using a field theoretic model for composite hadrons with quark (and antiquark) constituents. The medium modifications of the decay widths of ${\rm Y}(4S)$ to $B\bar{B}$ pair in magnetized matter arise due to the mass modifications of the decaying ${\rm Y}(4S)$ as well as of the produced $B$ and $\bar{B}$ mesons. The in-medium masses of the open bottom meson in magnetized nuclear matter are computed from their interactions with the nucleons and the scalar mesons within a chiral effective model. The mass modification of the ${\rm Y}(4S)$ arises due to the medium modification of a scalar dilaton field, which is introduced in the model to simulate the gluon condensates of QCD. The charged $B^{\pm }$ mesons have additional contributions from the Landau energy levels, leading to positive shifts in their masses in the presence of a magnetic field. In the presence of an external magnetic field, there are contributions to the masses of the $B$, $\bar{B}$ mesons and ${\rm Y}(4S)$ state (longitudinal component) due to the pseudoscalar meson-vector meson (PV) mixing ($B-B^{\ast }$, $\bar{B}-\overline{B^{\ast }}$ and ${\rm Y}(4S)-{\eta }_b(4S)$ mixings), which are also considered in the present study. The PV mixing effects are observed to be the dominant contributions to the mass shifts of these mesons, which lead to appreciable modifications in the decay widths of ${\rm Y}(4S)$ to the neutral ($B^0\overline{B^0}$) and the charged ($B^{+}{B}^{-}$) pairs in the presence of a magnetic field. These should have observable consequence in the production of open bottom mesons and bottomonium states at LHC and RHIC, where huge magnetic fields are produced in ultra-relativistic peripheral heavy ion collisions.

    ↳ nucl-thhep-phIJMPE(2022)·15 citations
14. 14*

    Thermodynamics of Antiferromagnetic Solids in Magnetic Fields

    Tomáš Brauner🇳🇴 · Christoph P. Hofmann🇲🇽

    We analyze the thermodynamic properties of antiferromagnetic solids subjected to a combination of mutually orthogonal uniform magnetic and staggered fields. Low-temperature series for the pressure, order parameter and magnetization up to two-loop order in the effective expansion are established. We evaluate the self-energy and the dispersion relation of the dressed magnons in order to discuss the impact of spin-wave interactions on thermodynamic observables.

    ↳ cond-mat.str-elhep-lathep-phAnnals Phys.(2020)·3 citations
15. 15*

    Large $N_c$ scaling of meson masses and decay constants

    Pilar Hernández🇪🇸 · Carlos Pena🇪🇸 · Fernando Romero-López🇪🇸

    We perform an $\text{ab initio}$ calculation of the $N_c$ scaling of the low-energy couplings of the chiral Lagrangian of low-energy strong interactions, extracted from the mass dependence of meson masses and decay constants. We compute these observables on the lattice with four degenerate fermions, $N_f=4$, and varying number of colours, $N_c=3-6$, at a lattice spacing of $a\simeq 0.075$ fm. We find good agreement with the expected $N_c$ scaling and measure the coefficients of the leading and subleading terms in the large $N_c$ expansion. From the subleading $N_c$ corrections, we can also infer the $N_f$ dependence, that we use to extract the value of the low-energy couplings for different values of $N_f$. We find agreement with previous determinations at $N_c=3$ and $N_f=2,3$ and also, our results support a strong paramagnetic suppression of the chiral condensate in moving from $N_f=2$ to $N_f=3$.

    ↳ hep-lathep-phEPJC(2019)·40 citations
16. 16*

    The BAO+BBN take on the Hubble tension

    Nils Schöneberg🇩🇪 · Julien Lesgourgues🇩🇪 · Deanna C. Hooper🇩🇪

    Many attempts to solve the Hubble tension with extended cosmological models combine an enhanced relic radiation density, acting at the level of background cosmology, with new physical ingredients affecting the evolution of cosmological perturbations. Several authors have pointed out the ability of combined Baryon Acoustic Oscillation (BAO) and Big Bang Nucleosynthesis (BBN) data to probe the background cosmological history independently of both CMB maps and supernovae data. Using state-of-the-art assumptions on BBN, we confirm that combined BAO, deuterium, and helium data are in tension with the SH0ES measurements under the $\Lambda$CDM assumption at the 3.2$\sigma$ level, while being in close agreement with the CMB value. We subsequently show that floating the radiation density parameter $N_{\mathrm{eff}}$ only reduces the tension down to the 2.6$\sigma$ level. This conclusion, totally independent of any CMB data, shows that a high $N_{\mathrm{eff}}$ accounting for extra relics (either free-streaming or self-interacting) does not provide an obvious solution to the crisis, not even at the level of background cosmology. To circumvent this strong bound, (i) the extra radiation has to be generated after BBN to avoid helium bounds, and (ii) additional ingredients have to be invoked at the level of perturbations to reconcile this extra radiation with CMB and LSS data.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·250 citations
17. 17*

    Probing heavy dark matter decays with multi-messenger astrophysical data

    Koji Ishiwata🇯🇵 · Oscar Macias🇯🇵 · Shin'ichiro Ando🇳🇱 · Makoto Arimoto🇯🇵

    We set conservative constraints on decaying dark matter particles with masses spanning a very wide range ($10^4-10^{16}$ GeV). For this we use multimessenger observations of cosmic-ray (CR) protons/antiprotons, electrons/positrons, neutrinos/antineutrinos and gamma rays. Focusing on decays into the $\bar{b}b$ channel, we simulate the spectra of dark matter yields by using the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations and the $\text{Pythia}$ package. We then propagate the CRs of dark matter origin till Earth by using the state-of-the-art numerical frameworks $\text{CRPropa}$, $\text{GALPROP}$ and $\text{HelMod}$ for the solution of the CR transport equation in the extragalactic, Galactic region and the heliosphere, respectively. Conservative limits are obtained by requiring that the predicted dark matter spectra at Earth be less than the observed CR spectra. Overall, we exclude dark matter lifetimes of $10^{28}$ s or shorter for all the masses investigated in this work. The most stringent constraints reach $10^{30}$ s for very heavy dark matter particles with masses in the range $10^{11}-10^{14}$ GeV.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2020)·66 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.