Fri·Nov 2, 2018Friday·November 2, 2018

1. 01*

   Further signatures to support the tetraquark mixing framework for the two light-meson nonets

   Hungchong Kim🇰🇷 · K. S. Kim🇰🇷 · Myung-Ki Cheoun🇰🇷 · Daisuke Jido🇯🇵 · Makoto Oka🇯🇵

   In this work, we investigate additional signatures to support the tetraquark mixing framework that has been recently proposed as a possible structure for the two nonets, namely $a_0(980)$, $K_0^{\ast }(800)$, $f_0(500)$, $f_0(980)$ in the light nonet, $a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$ in the heavy nonet. First, we advocate that the two nonets form the flavor nonet approximately satisfying the Gell-Mann--Okubo mass relation. Then we reexamine the mass ordering generated from the tetraquark nonets and show that this mass ordering is satisfied by the two nonets although the ordering in the heavy nonet is marginal. The marginal mass ordering however can be regarded as another signature for tetraquarks because it can be explained partially by the hyperfine masses calculated from the tetraquark mixing framework. The tetraquark mixing parameters are found to be independent of isospins giving additional support for the formation of the flavor nonets. In addition, we discuss the other approaches like two-quark pictures or meson-meson bound states, and their possible limitations in explaining the two nonets. As a peculiar signature distinguished from other approaches, we investigate the fall-apart coupling strengths into two vector mesons from our tetraquarks. Coupling strengths into the two-vector modes are found to enhance strongly in the heavy nonet while they are suppressed in the light nonet. The coupling ratios, which depend on the isospin channel, are found to be huge around $\sim 15$. This trend in the two-vector modes, which is opposite to that in the two-pseudoscalar fall-apart modes, can provide another testing ground for the tetraquark mixing framework. Some experimental evidences related to the phenomena are discussed particularly from the resonances belonging to the heavy nonet.

   hep-phhep-exhep-latnucl-thPRD(2019)·20 citations
2. 02*

   Decay properties of singly charmed baryons

   Keval Gandhi🇮🇳 · Zalak Shah🇮🇳 · Ajay Kumar Rai🇮🇳

   The magnetic moments, transition magnetic moments and the radiative decay widths of singly charmed baryons are calculated with ${J^P=\frac{1}{2}}^{+}$ and ${J^P=\frac{3}{2}}^{+}$ in the constitute quark model. Further, the strong decay rates for $S$, $P$ and $D$ wave transitions are also presented. The singly charmed baryon masses used in the calculations were obtained from the hypercentral Constitute Quark Model (hCQM) without and with first order relativistic correction. Obtained results are compared with experimental observation as well as with the other theoretical predictions.

   hep-phEur.Phys.J.Plus(2018)·44 citations
3. 03*

   Unitarity and CP violation in leptogenesis at NLO: general considerations and top Yukawa contributions

   J. Racker🇦🇷

   With an emphasis on unitarity and CPT requirements, we study the inclusion of CP-violating processes in baryogenesis at next-to-leading order, particularly those involving the top Yukawa interaction in leptogenesis. We show that there are more contributions than previously considered, but also important cancellations. Some of these involve the interference of connected with disconnected diagrams. We also discuss on the application of the Kinoshita-Lee-Nauenberg theorem to treat the infrared divergences that are common at next-to-leading order. Finally, we calculate the CP asymmetry in the three-body decay of a sterile neutrino into a lepton and top quarks.

   hep-phhep-thJHEP(2019)·16 citations
4. 04*

   Proof of sum rules for double parton distributions in QCD

   Markus Diehl🇩🇪 · Peter Ploessl🇩🇪 · Andreas Schafer🇩🇪

   Double hard scattering can play an important role for producing multiparticle final states in hadron-hadron collisions. The associated cross sections depend on double parton distributions, which at present are only weakly constrained by theory or measurements. A set of sum rules for these distributions has been proposed by Gaunt and Stirling some time ago. We give a proof for these sum rules at all orders in perturbation theory, including a detailed analysis of the renormalisation of ultraviolet divergences. As a by-product of our study, we obtain the form of the inhomogeneous evolution equation for double parton distributions at arbitrary perturbative order.

   hep-phEPJC(2019)·39 citations
5. 05*

   The light scalar $K_0^{\ast }(700)$ in the vacuum and at nonzero temperature

   Francesco Giacosa🇵🇱

   There is mounting evidence toward the existence of a light scalar kaon $\kappa \equiv$ $K_0^{\ast }(700)$ with quantum numbers $I(J^P)=\frac{1}{2}(0^{+}).$ Here, we recall the results of an effective model with both derivative and non-derivative terms in which only one scalar kaonic field is present in the Lagrangian (the standard quark-antiquark ,,seed\textquotedblright\ state $K_0^{\ast }(1430)$): a second \textquotedblleft companion\textquotedblright\ pole $K_0^{\ast }(700)$ emerges as a dynamically generated state. A related question is the role of $K_0^{\ast }(700)$ at nonzero $T$: since it is the lightest scalar strange state, one would naively expect that it is relevant for $\pi$ and $K$ multiplicities. However, a repulsion in the $\pi K$ channel with $I=3/2$ cancels its effect.

   hep-ph3 citations
6. 06*

   Note on the gluino condensate in supersymmetric Yang Mills theory

   Renata Jora🇷🇴

   We calculate gluino condensate for supersymmetric Yang Mills theory on general grounds without making any assumption with regard to the weak or strong regime of the theory. Our result coincides with that obtained from an instanton superpotential when the theory is weakly interacting. The method also determines the corresponding partition function.

   hep-ph0 citations
7. 07*

   Comment on some particular phases of supersymmetric QCD

   Renata Jora🇷🇴

   We study two phases of supersymmetric QCD associated to the singularities of the renormalization constant of the fermion mass operator. We find a behavior of the potential between two charges for the phases of interest that it is consistent with Seiberg results on these aspects based on a different method.

   hep-phhep-th0 citations
8. 08*

   Radiative Corrections to Triple Higgs Coupling and Electroweak Phase Transition: Beyond One-loop Analysis

   Eibun Senaha🇰🇷

   We evaluate dominant two-loop corrections to the triple Higgs coupling and strength of a first-order electroweak phase transition in the inert Higgs doublet model. It is found that sunset diagrams can predominantly enhance the former and reduce the latter. As a result, the triple Higgs coupling normalized by the standard model value at two-loop level is more enhanced than the corresponding one-loop value.

   hep-phPRD(2019)·55 citations
9. 09*

   Like-sign dileptons with mirror type composite neutrinos at the HL-LHC

   Matteo Presilla🇮🇹 · Roberto Leonardi🇮🇹 · Orlando Panella🇮🇹

   Within a mirror type assignment for the excited composite fermions the neutrino mass term is built up from a Dirac mass, $m_{\ast }$, which gives the mass of charged lepton component of the $SU(2)$, right-handed, doublet, and a Majorana mass, $m_L$, for the left-handed component (singlet) of the excited neutrino. The mass matrix is diagonalized leading to two Majorana mass eigenstates. The active neutrino field ${\nu }_R^{\ast }$ is thus a superposition of the two mass eigenstates with mixing coefficients which depend on the ratio $m_L/m_{\ast }$. We discuss the prospects of discovery of these physical states at the HL-LHC as compared with the previous searches of composite Majorana neutrinos at the LHC based on sequential type Majorana neutrinos.

   hep-ph4 citations
10. 10*

    A Comparison of p-p, p-Pb, Pb-Pb Collisions in the Thermal Model: Multiplicity Dependence of Thermal Parameters

    Natasha Sharma🇮🇳 · Jean Cleymans🇿🇦 · Boris Hippolyte🇫🇷 · Masimba Paradza🇿🇦

    % An analysis is made of the particle composition (hadrochemistry) of the final state in proton-proton (p-p), proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions as a function of the charged particle multiplicity ($\text{dNchdeta}$). The thermal model is used to determine the chemical freeze-out temperature as well as the radius and strangeness saturation factor ${\gamma }_s$. Three different ensembles are used in the analysis namely, the grand canonical ensemble, the canonical ensemble with exact strangeness conservation and the canonical ensemble with exact baryon number, strangeness and electric charge conservation. It is shown that for high multiplicities (at least 20 charged hadrons in the mid-rapidity interval considered) the three ensembles lead to the same results.

    hep-phnucl-thPRC(2019)·73 citations
11. 11*

    Signatures of supersymmetry and a $L_{\mu }-L_{\tau }$ gauge boson at Belle-II

    Heerak Banerjee🇮🇳 · Sourov Roy🇮🇳

    We propose that the $\gamma +E/$ signal at the Belle-II will be a smoking gun for supersymmetry (SUSY) in the presence of a gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry. A striking consequence of breaking the enhanced symmetry in the limit of degenerate (s)leptons is the nondecoupling of the radiative contribution of heavy charged sleptons, appearing in SUSY, to the $\gamma -Z^{\prime }$ kinetic mixing. The signal process, $e^{+}{e}^{-}\to \gamma Z^{\prime }\to \gamma +E/$, is an outcome of this ubiquitous feature. We take into account the severe constraints on gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ models by several low-energy observables and show that any significant excess in all but the highest photon energy bin would be an undeniable signature of such heavy scalar fields in SUSY coupling to $Z^{\prime }$. The number of signal events depends crucially on the logarithm of the ratio of stau to smuon mass in the presence of SUSY. In addition, the number is also inversely proportional to the $e^{+}-e^{-}$ collision energy, making a low-energy, high-luminosity collider like Belle-II an ideal testing ground for this channel. This process can probe large swathes of the slepton mass ratio vs the additional gauge coupling ($g_X$) parameter space. More importantly, it can explore the narrow slice of $M_{Z^{\prime }}-g_X$ parameter space still allowed in gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ models for superheavy sparticles.

    hep-phhep-exPRD(2019)·28 citations
12. 12*

    Single and double nonlinear Compton scattering

    Victor Dinu🇷🇴 · Greger Torgrimsson🇩🇪

    We study single, double and higher-order nonlinear Compton scattering where an electron interacts nonlinearly with a high-intensity laser and emits one, two or more photons. We study, in particular, how double Compton scattering is separated into one-step and two-step parts, where the latter is obtained from an incoherent product of two single-photon emissions. We include all contributions to double Compton scattering and show that the exchange term, which was not calculated in previous constant-crossed field studies, is in general on the same order of magnitude as the other one-step terms. Our approach reveals practically useful similarities between double Compton scattering and the trident process, which allows us to transfer some of our previous results for trident to double Compton scattering. We provide a new gluing approach for obtaining the dominant contribution to higher-order Compton scattering for long laser pulses. Unlike the standard gluing approach, our new approach does not require the intensity parameter $a_0$ to be much larger than one. For `hard' photons we obtain several saddle-point approximations for various field shapes.

    hep-phhep-thPRD(2019)·55 citations
13. 13*

    Probing Lorentz violation effects via a laser beam interacting with a high-energy charged lepton beam

    Seddigheh Tizchang🇮🇷 · Rohoollah Mohammadi🇮🇷 · She-Sheng Xue🇮🇹

    In this work, the conversion of linear polarization of a laser beam to circular one through its forward scattering by a TeV order charged lepton beam in the presence of Lorentz violation correction is explored. We calculate the ratio of circular polarization to linear one (Faraday Conversion phase $\Delta {\varphi }_{\mathrm{FC}}$) of the laser beam interacting with either electron or the muon beam in the framework of the quantum Boltzmann equation. Regarding the experimentally available sensitivity to the Faraday conversion $\Delta {\varphi }_{\mathrm{FC}}\simeq 10^{-3}-10^{-2}$, we show that the scattering of a linearly polarized laser beam with energy $k_0\sim 0.1$ eV and an electron/muon beam with flux ${\overline{ϵ}}_{e,\mu }\sim 10^{10}/10^{12}$ TeV cm${}^{-2}$ s${}^{-1}$ places an upper bound on the combination of lepton sector Lorentz violation coefficients $c_{\mu \nu }$ components $(c_{TT}+1.4c_{(TZ)}+0.25(c_{XX}+c_{YY}+2c_{ZZ}))$. The obtained bound on the combination for the electron beam is at the $4.35\times 10^{-15}$ level and for the muon beam at the $3.9\times 10^{-13}$ level. It should be mentioned that the laser and charged lepton beams considered here to reach the experimentally measurable $\Delta {\varphi }_{\mathrm{FC}}$ are currently available or will be accessible in the near future. This study provides a valuable supplementary to other theoretical and experimental frameworks for measuring and constraining Lorentz violation coefficients.

    hep-phhep-thEPJC(2019)·8 citations
14. 14*

    Mono-Higgs Signature in the Scotogenic Model with Majorana Dark Matter

    Amine Ahriche🇩🇿 · Abdesslam Arhrib🇲🇦 · Adil Jueid🇨🇳 · Salah Nasri🇦🇪 · Alejandro de la Puente🇺🇸

    We study the phenomenology of scotogenic model in the case of Majorana Dark Matter (DM) candidate. This scenario gives important consequences since the parameter space of the model is almost unconstrained compared to the Inert Higgs Doublet Model (or the scotogenic model with scalar DM), and hence, offers new opportunities for discovery at future high energy collider, e.g. the HL-LHC. As an example, we focus on the production of the Standard Model (SM) Higgs boson in association with a pair of dark scalars. Owing to its clean signature, the $\gamma \gamma$ decay channel of the SM Higgs boson is investigated in great detail at both the HL-LHC (at $\sqrt{s}=14$ TeV) and the future FCC-hh (at $\sqrt{s}=100$ TeV). After revisiting the LHC constraints from run-II on the parameter space of the model, and selecting benchmark points satisfying all the theoretical and experimental constraints, we found that scalars with mass up to $140$ GeV ($160$ GeV) can be probed at the LHC (FCC-hh) with a $3$ ab${}^{-1}$ of integrated luminosity assuming $5\%$ of uncertainty.

    hep-phPRD(2020)·31 citations
15. 15*

    Simulation studies for the MADMAX axion direct detection experiment

    Jan Schütte-Engel (on behalf of the MADMAX collaboration)🇩🇪

    We present a general approach to solve the Maxwell-axion equations for arbitrary geometries and materials. The approach is based on the finite element method (FEM) and applied to experimental setups related to the new MADMAX (MAgnetized Disc and Mirror Axion eXperiment) project. Analytical methods are used to verify the FEM simulations. MADMAX is a dielectric haloscope which will utilize axion-photon conversion at many dielectric interfaces and probe axions in the mass range $m_a=40-400\mu \text{eV}$.

    hep-phhep-ex4 citations
16. 16*

    Analysis and implications of precision near-forward TOTEM data

    Giulia Pancheri🇮🇹 · Simone Pacetti🇮🇹 · Yogendra Srivastava🇮🇹

    Very precise data on elastic proton-proton scattering at $\sqrt{s}=7$, $8$ and $13$ TeV have been obtained by the TOTEM group at LHC in the near-forward region (momentum transfers down to $|t|=6\times 10^{-4}{\mathrm{GeV}}^2$ at $\sqrt{s}=8$ TeV and to $|t|=8\times 10^{-4}{\mathrm{GeV}}^2$ at $\sqrt{s}=13$ TeV). The Coulomb-nuclear interference has been measured with sufficient accuracy for TOTEM to establish the falloff of the $\rho$ parameter with increasing energy. The predictions from a previously studied model are shown to be in good agreement with the data and thus allow us to draw rather firm conclusions about the structure of the near-forward nuclear amplitude. We point out that due to a zero in the real part of the nuclear amplitude occurring at a very small momentum transfer--that can migrate into the Coulomb-nuclear interference (CNI) region at higher energies--much care is needed in extracting the numerical value of $\rho$ for such energies. Thus, the true value of $\rho$ would be higher than the TOTEM value for $\rho$ found under the hypothesis that the real part of the elastic nuclear amplitude is devoid of such a zero in the CNI region.

    hep-phhep-exPRD(2019)·26 citations
17. 17*

    Light Dark Matter at Neutrino Experiments

    Yohei Ema🇩🇪 · Filippo Sala🇩🇪 · Ryosuke Sato🇩🇪

    Sub-GeV Dark Matter particles upscattered by cosmic rays gain enough kinetic energy to pass the thresholds of large volume detectors on Earth. We then use public Super-Kamiokande and MiniBooNE data to derive a novel limit on the scattering cross section of Dark Matter with electrons that extends down to sub-keV masses, closing a previously allowed wide region of parameter space. We finally discuss search strategies and prospects at existing and planned neutrino facilities.

    hep-phastro-ph.HEhep-exPRL(2019)·238 citations
18. 18*

    Dark Energy and the Refined de Sitter Conjecture

    Prateek Agrawal🇺🇸 · Georges Obied🇺🇸

    We revisit the phenomenology of quintessence models in light of the recently refined version of the de Sitter Swampland conjecture, which includes the possibility of unstable de Sitter critical points. We show that models of quintessence can evade previously derived lower bounds on $(1+w)$, albeit with very finely-tuned initial conditions. In the absence of such tuning or other rolling quintessence fields, a field with mass close to Hubble is required, which has a generic prediction for $(1+w)$. Slow-roll single field inflation models remain in tension. Other phenomenological constraints arising from the coupling of the quintessence field with the Higgs or the QCD axion are significantly relaxed.

    hep-phastro-ph.COJHEP(2019)·59 citations
19. 19*

    A Solar System Test of Self-Interacting Dark Matter

    Cristian Gaidau🇺🇸 · Jessie Shelton🇺🇸

    Dark matter (DM) self-interactions affect the gravitational capture of DM in the Sun and Earth differently as a simple consequence of the differing kinematics of collisions within the two potential wells: the dominant effect of self-interactions in the Sun is to provide an additional channel for capture, while the dominant effect in the Earth is to eject previously captured DM. We point out that this simple observation can be used to deduce the existence of DM self-interactions by comparing the annihilation rates of DM gravitationally bound within the Sun and Earth. We compute the Sun and Earth annihilation fluxes for DM with spin-independent nuclear cross-sections and thermal annihilation cross-sections and demonstrate that, for cross-sections allowed by direct detection, self-interactions can easily suppress the expected Earth flux by multiple orders of magnitude. This suppression is potentially significant even for self-interaction cross-sections orders of magnitude below the Bullet Cluster bounds, making this solar system comparison a leading test of dark matter self-interactions. Additionally, we consider thermalization of the captured DM population with the nuclei of the capturing body in some detail, accounting for both nuclear and self-interactions, and point out some consequential and broadly applicable considerations.

    hep-phastro-ph.HEJCAP(2019)·14 citations
20. 20*

    Early Cosmological Period of QCD Confinement

    Seyda Ipek🇺🇸 · Tim Tait🇺🇸

    If the strong coupling is promoted to a dynamical field-dependent quantity, it is possible that the strong force looked very different in the early Universe. We consider a scenario in which the dynamics is such that QCD confines at high temperatures with a large dynamical scale, relaxing back to ~1 GeV before big bang nucleosynthesis. We discuss the cosmological implications and explore potential applications, including fleshing out a new mechanism for baryogenesis which opens up if QCD confines before the electroweak phase transition of the Standard Model.

    hep-phPRL(2019)·60 citations
21. 21*

    Electroweak Multiplet Dark Matter at Future Lepton Colliders

    Kenji Kadota🇰🇷 · Andrew Spray🇰🇷

    An electroweak multiplet stable due to a new global symmetry is a simple and well-motivated candidate for thermal dark matter. We study how direct searches at a future linear collider, such as the proposed CLIC, can constrain scalar and fermion triplets, quintets and septets, as well as a fermion doublet. The phenomenology is highly sensitive to charged state lifetimes and thus the mass splitting between the members of the multiplet. We include both radiative corrections and the effect of non-renormalisable operators on this splitting. In order to explore the full range of charged state lifetimes, we consider signals including long-lived charged particles, disappearing tracks, and monophotons. By combining the different searches we find discovery and exclusion contours in the mass-lifetime plane. In particular, when the mass splitting is generated purely through radiative corrections, we can exclude the pure-Higgsino doublet below 310 GeV, the pure-wino triplet below 775 GeV, and the minimal dark matter fermion quintet below 1025 GeV. The scenario where the thermal relic abundance of a Higgsino accounts for the whole dark matter of the Universe can be excluded if the mass splitting between the charged and neutral states is less than 230 MeV. Finally, we discuss possible improvements to these limits by using associated hard leptons to idenify the soft visible decay products of the charged members of the dark matter multiplet.

    hep-phJHEP(2019)·14 citations
22. 22*

    Why The Cosmological Constant is a Boundary Condition

    Tom Banks🇺🇸 · Willy Fischler🇺🇸

    We review arguments that the cosmological constant (c.c.) should not be thought of as a local contribution to the energy density, but rather as an infrared boundary condition specifying particular models of quantum gravity.

    ↳ hep-thgr-qchep-ph13 citations
23. 23*

    Strangeons constitute bulk strong matter-- To test using GW170817

    Xiaoyu Lai🇨🇳 · Enping Zhou🇩🇪 · Renxin Xu🇨🇳

    The fundamental strong interaction determines the nature of pulsar-like compact stars which are essentially in the form of bulk strong matter. From an observational point of view, it is proposed that bulk strong matter could be composed of strangeons, i.e. quark-clusters with there-light-flavor symmetry of quarks, and therefore pulsar-like compact objects could actually be strangeon stars. The equation of state (EOS) of strangeon stars is described in a Lennard-Jones model for the purpose of constraining the EOS by both the tidal deformability $\Lambda$ of GW170817 and $M_{\mathrm{TOV}}$. It is found that the allowed parameter space is quite large as most of the Lennard-Jones EOS models satisfy the tidal deformability constraint by GW170817. The future GW detections for smaller values of $\Lambda$ and mass measurement for larger values of $M_{\mathrm{TOV}}$ will help a better constraint on the strangeon star model.

    ↳ astro-ph.HEhep-phEPJA(2019)·41 citations
24. 24*

    Old and New in Strangeness Nuclear Physics

    Avraham Gal🇮🇱

    Several persistent problems in strangeness nuclear physics are discussed in this opening talk at HYP2018, Portsmouth-Norfolk VA, June 2018: (i) the ${}_{\Lambda }^3$H and ${}_{\Lambda }^3$n (if existing) lifetimes; (ii) charge symmetry breaking in $\Lambda$ hypernuclei; (iii) the overbinding of ${}_{\Lambda }^5$He which might be related to the hyperon puzzle in neutron stars; and (iv) does ${\Lambda }^{\ast }$(1405) survive in strange hadronic matter?

    ↳ nucl-thhep-phnucl-exAIP Conf.Proc.(2019)·2 citations
25. 25*

    Progress in the lattice simulations of Sp(2N) gauge theories

    Jong-Wan Lee🇰🇷 · Ed Bennett🇬🇧 · Deog Ki Hong🇰🇷 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇹

    We report on the status of our programme to simulate Sp($2N$) gauge theories on the lattice. Motivated by the potential realization of an SU($4$)/Sp($4$)$\sim$SO($6$)/SO($5$) composite Higgs model and the applications to self interacting dark matter, we first perform dynamical simulations of Sp($4$) theories with two Dirac flavors in the fundamental representation. Preliminary results of the meson spectrum are presented, along with discussion of the lattice systematics. We also introduce two-index anti-symmetric Dirac fermions. Such fermions are relevant in the context of partial top compositeness, provided they carry SU($3$) color quantum numbers, and hence we introduce three (Dirac) copies of them. We present the quenched meson spectrum and explore the phase space of bare lattice parameters. For all the numerical simulations we use the standard Wilson lattice gauge and fermion actions.

    ↳ hep-lathep-phPoS(2018)·39 citations
26. 26*

    Lambda polarization in heavy ion collisions: from RHIC BES to LHC energies

    Iurii Karpenko🇫🇷 · Francesco Becattini🇮🇹

    STAR collaboration at RHIC has recently measured the polarization of $\Lambda$ hyperons in non-central heavy ion collisions in the RHIC Beam Energy Scan (BES) program. The magnitude of the polarization was found to decrease from few percents at the lowest BES energies to $\approx 0.2$% at the top RHIC energy. The polarization signal has been reproduced in different hydrodynamic calculations assuming a thermodynamic spin-vorticity coupling mechanism at the Cooper-Frye hypersurface. In this work an extension of our existing calculations of the $\Lambda$ polarization in the RHIC BES program to the top RHIC and 2.76 TeV LHC energies is presented. The longitudinal component of the $\Lambda$ polarization, which is the dominant component of the polarization at the LHC energies, is discussed. Finally we show that the global polarization of $\Lambda$ originates dominantly from the relativistic analogue of the classical vorticity, whereas the quadrupole longitudinal component originates from the gradients of temperature and acceleration of the medium when the $\Lambda$s are produced out of the fluid.

    ↳ nucl-thhep-phnucl-exNPA(2019)·31 citations
27. 27*

    Effect of the Pauli exclusion principle in the electric dipole moment of ${}^9$Be with $|\Delta S|=1$ interactions

    Jehee Lee🇯🇵 · Nodoka Yamanaka🇫🇷 · Emiko Hiyama🇯🇵

    We calculate the contribution of the $|\Delta S|=1$ $K$ meson exchange process generated by the Cabibbo-Kobayashi-Maskawa matrix to the electric dipole moment (EDM) of the ${}^9$Be nucleus by considering the $\alpha n-\alpha \Lambda$ channel coupling. It is found that the effect of the Pauli exclusion principle is not important intermediate $S=-1$ state, and that the result is consistent with the EDM of ${}^9$Be calculated with the $|\Delta S|=1$ interactions as a perturbation without considering the nucleus-hypernucleus mixing. Our result suggests that the effect of the $|\Delta S|=1$ interactions is neither suppressed nor enhanced in nuclei, if the difference of binding energies between the nucleus and the hypernucleus is small compared to the hyperon-nucleon mass difference.

    ↳ nucl-thhep-phPRC(2019)·16 citations
28. 28*

    On chiral extrapolations of coupled-channel reaction dynamics for charmed mesons

    Xiao-Yu Guo🇩🇪 · Yonggoo Heo🇹🇭 · Matthias F.M. Lutz🇩🇪

    We perform an analysis of QCD lattice data on masses of charmed meson with J^P = 0^- and J^P =1^- quantum numbers. The quark-mass dependence of the data set is used to gain information on the size of counter terms in the chiral Lagrangian formulated with open-charm mesons. Of particular interest are those counter terms that are active in the exotic flavour sextet channel. A chiral expansion scheme is developed and applied to the lattice data set. An accurate reproduction of the lattice data based on ensembles of PACS-CS, MILC, ETMC and HSC with pion and kaon masses smaller than 600 MeV is achieved. It is argued that a unique set of low-energy parameters is obtainable only if additional information from an HSC ensemble on some scattering phase shifts is included in our global fits. Based on such low-energy parameters we find a clear signal for a member of the exotic flavour sextet states in the pi D phase shift, between the eta D and bar K D_s thresholds. A striking dependence of such phase shifts on the values of the up, down and strange quarks is predicted.

    ↳ hep-lathep-phPoS(2018)·7 citations
29. 29*

    A non-relativistic magnetized vector boson gas at any temperature

    L. C. Suárez-González🇨🇺 · G. Quintero Angulo🇨🇺 · A. Pérez Martínez🇨🇺 · H. Pérez Rojas🇨🇺

    We study the thermodynamic properties of a neutral vector boson gas in presence of a constant magnetic field, by means of a semi-classical approach that allows to introduce the spin in the non-relativistic spectrum of the bosons. Bose-Einstein condensation is obtained and it turns out to depend on all the parameters involved in the problem: temperature, particle density and magnetic field. An spontaneous magnetization appears at low temperature as a consequence of the condensed state. The axial symmetry imposed in the system by the magnetic field presence, splits the pressure in two components, one along and another perpendicular to the magnetic axis. Under certain conditions, the perpendicular pressure becomes negative signaling that the system undergoes a transversal magnetic collapse. The spontaneous magnetization might be useful to model magnetic field production inside compact stars, while the negative pressures imposes certain limits to the temperatures and densities needed inside these objects to support a given magnetic field.

    ↳ cond-mat.quant-gashep-phJ.Phys.Conf.Ser.(2019)·8 citations
30. 30*

    Vibrational modes of Skyrmions

    Sven Bjarke Gudnason🇯🇵 · Chris Halcrow🇬🇧

    We study the vibrational modes of Skyrmions with baryon numbers one through eight in the standard Skyrme model. The vibrational modes are found in the harmonic approximation around the classical soliton solution and the real parts of the frequencies of the modes are extracted. We further classify the vibrational modes into representations of the symmetries possessed by the Skyrmion solutions. We find that there are approximately 7B low-lying modes for a Skyrmion with baryon number B, in addition to an infinite continuum of scattering modes. This result suggests that the instanton moduli space, which is 8B-dimensional, does not accurately describe the deformation space of Skyrmions as previously conjectured.

    ↳ hep-thhep-phPRD(2018)·30 citations
31. 31*

    General Treatment of Reflection of Spherical Electromagnetic Waves from a Spherical Surface and its Implications for the ANITA Anomalous Polarity Events

    Paramita Dasgupta🇮🇳 · Pankaj Jain🇮🇳

    We develop a general formalism to treat reflection of spherical electromagnetic waves from a spherical surface. Our main objective is interpretation of radio wave signals produced by cosmic ray interactions with Earth's atmosphere which are observed by the Antarctica based ANITA detector after reflection off the ice surface. The incident wave is decomposed into plane waves and each plane wave is reflected off the surface using the standard Fresnel formalism. For each plane wave the reflected wave is assumed to be locally a plane wave. This is a very reasonable assumption and there are no uncontrolled approximations in our treatment of the reflection phenomenon. The surface roughness effects are also included by using a simple model. We apply our formalism to the radiation produced by the balloon-borne HiCal radio-frequency (RF) transmitter. Our final results for the reflected power are found to be in good agreement with data for all elevation angles. We also study the properties of reflected radio pulses in order to study their phase relationship with direct pulses. We find that for some roughness models the pulse shape can be somewhat distorted and may be misidentified as a direct pulse. However this is a rather small effect and is unable to provide an explanation for the observed mystery events by ANITA.

    ↳ physics.class-phhep-exhep-phAstropart.Phys.(2021)·8 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.