Tue·Oct 8, 2019Tuesday·October 8, 2019

1. 01*

   Dirac Materials for Sub-MeV Dark Matter Detection: New Targets and Improved Formalism

   R. Matthias Geilhufe🇸🇪 · Felix Kahlhoefer🇩🇪 · Martin Wolfgang Winkler🇸🇪

   Because of their tiny band gaps Dirac materials promise to improve the sensitivity for dark matter particles in the sub-MeV mass range by many orders of magnitude. Here we study several candidate materials and calculate the expected rates for dark matter scattering via light and heavy dark photons as well as for dark photon absorption. A particular emphasis is placed on how to distinguish a dark matter signal from background by searching for the characteristic daily modulation of the signal, which arises from the directional sensitivity of anisotropic materials in combination with the rotation of the Earth. We revisit and improve previous calculations and propose two new candidate Dirac materials: BNQ-TTF and Yb${}_3$PbO. We perform detailed calculations of the band structures of these materials and of ZrTe${}_5$ based on density functional theory and determine the band gap, the Fermi velocities and the dielectric tensor. We show that in both ZrTe${}_5$ and BNQ-TTF the amplitude of the daily modulation can be larger than 10% of the total rate, allowing to probe the preferred regions of parameter space even in the presence of sizeable backgrounds. BNQ-TTF is found to be particularly sensitive to small dark matter masses (below 100 keV for scattering and below 50 meV for absorption), while Yb${}_3$PbO performs best for heavier particles.

   hep-phcond-mat.mtrl-scihep-exPRD(2020)·121 citations
2. 02*

   All two-loop scalar self-energies and tadpoles in general renormalisable field theories

   Mark D. Goodsell🇫🇷 · Sebastian Paßehr🇫🇷

   We calculate the complete tadpoles and self-energies at the two-loop order for scalars in general renormalisable theories, a crucial component for calculating two-loop electroweak corrections to Higgs-boson masses or for any scalar beyond the Standard Model. We renormalise the amplitudes using mass-independent renormalisation schemes, based on both dimensional regularisation and dimensional reduction. The results are presented here in Feynman gauge, with expressions for all 121 self-energy and 25 tadpole diagrams given in terms of scalar and tensor integrals with the complete set of rules to reduce them to a minimal basis of scalar integrals for any physical kinematic configuration. In addition, we simplify the results to a set of only 16 tadpole and 58 self-energy topologies using relations in order to substitute the ghost and Goldstone-boson couplings that we derive. To facilitate their application, we also provide our results in electronic form as a new code TLDR. We test our results by applying them to the Standard Model and compare with analytic expressions in the literature.

   hep-phEPJC(2020)·27 citations
3. 03*

   Expanded empirical formula for Coulomb final state interaction in the presence of Lévy sources

   Máté Csanád🇭🇺 · Sándor Lökös🇭🇺 · Márton Nagy🇭🇺

   Measurements of momentum space correlations in heavy ion reactions are a unique tools to investigate the properties of the created medium. However, these analyses require the careful handling of the final state interactions such as the Coulomb repulsion of the involved particles. In small systems such as $e^{+}+e^{-}$ or $p+p$ the well-known Gamow factor gives an acceptable description but in the case of extended sources like that are created in heavy ion collisions, a more sophisticated approach has to be developed. In this paper we expand our previous work on the investigation of the Coulomb final state interaction in the presence of a Lévy source. Such sources were shown to be a statistically acceptable assumption to describe the quantumstatistical correlation functions in high energy heavy ion reactions.

   hep-phnucl-thPhys.Part.Nucl.(2020)·18 citations
4. 04*

   Chiral transition and meson melting with finite chemical potential in an improved soft-wall AdS/QCD Model

   Zhen Fang🇨🇳 · Lin Zhang🇨🇳

   We give a further study on the improved soft-wall AdS/QCD model with two flavors. The chiral transition behaviors are studied in the case of finite chemical potential, with the chiral phase diagram obtained at zero quark mass. The thermal spectral functions of the vector and axial-vector mesons are calculated, and the in-medium melting properties of the mesons are investigated. We find that the chiral transition behaviors and the meson melting properties at finite chemical potential can be qualitatively described by the improved soft-wall AdS/QCD model, except in the region of large chemical potential. The reason for these inadequate descriptions may be that the background geometry adopted in the model is not a dynamical one which is able to produce the QCD equation of state. To give a quantitative description for these low-energy phenomenologies, we shall consider a more consistent AdS/QCD model which treats the background fields and the chiral fields on the same footing.

   hep-ph7 citations
5. 05*

   Probing model-independent limits on $W^{+}{W}^{-}\gamma$ triple gauge boson vertex at the LHeC and the FCC-he

   A. Gutiérrez-Rodríguez🇲🇽 · M. Köksal🇹🇷 · A. A. Billur🇹🇷 · M. A. Hernández-Ruíz🇲🇽

   We study the cross-section of production of a single $W^{-}$ boson in association with a neutrino through the process $e^{-}p\to e^{-}{\gamma }^{\ast }p\to {\nu }_e{W}^{-}p$. Additionally, we obtain the anomalous couplings $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ of the $W^{+}{W}^{-}\gamma$ vertex at the Large Hadron Electron Collider (LHeC) and the Future Circular Collider Hadron-Electron (FCC-he). The impact of the polarized beam due to the electron is also analyzed. Our best limits for $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ at the $95\%$ C.L. are: $\Delta {\kappa }_{\gamma }=\pm 0.0017$, ${\lambda }_{\gamma }=\pm 0.0053$ (unpolarized electron beam) and $\Delta {\kappa }_{\gamma }=\pm 0.0013$, ${\lambda }_{\gamma }=\pm 0.0046$ (polarized electron beam) identifying the $W^{-}$ boson through the hadronic decay channel. In addition, the $e^{-}{\gamma }^{\ast }\to {\nu }_e{W}^{-}$ collision is one of the clean, pure and simple process to investigate the $W^{+}{W}^{-}\gamma$ coupling without the complications of QCD backgrounds.

   hep-phJ.Phys.G(2020)·20 citations
6. 06*

   Pomeron/glueball and odderon/oddball trajectories

   István Szanyi🇭🇺 · László Jenkovszky🇺🇦 · Rainer Schicker🇩🇪 · Volodymyr Svintozelskyi🇺🇦

   We predict glueball/oddball resonances lying on the pomeron/odderon trajectories. A simple new form of the trajectories, with threshold and asymptotic behaviour required by analyticity and unitarity, is proposed. The parameters of these (pomeron and odderon) trajectories are fitted to the data on high-energy elastic proton-proton scattering. The fitted trajectories are extrapolated to the resonance region to predict masses and widths of glueballs and oddballs. The (pomeron and odderon) trajectories may be used to calculate processes of central exclusive diffraction (CED).

   hep-phNPA(2020)·31 citations
7. 07*

   Pomeron-pomeron scattering

   István Szanyi🇭🇺 · Volodymyr Svintozelskyi🇺🇦

   Central exclusive diffractive (CED) production of meson resonances potentially is a factory producing new particles, in particular a glueball. The produced resonances lie in trajectories with vacuum quantum numbers, essentially on the pomeron trajectory. A tower of resonance recurrences, the production cross section and the resonances widths are predicted. A new feature is the form of the non-linear pomeron trajectory, producing resonances (glueballs) with increasing widths. At LHC energies, in the nearly forward direction the $t$-channel both in elastic, single or double diffraction dissociation as well as in CED is dominated by pomeron exchange (the role of secondary trajectories is negligible, however a small contribution from the odderon may be present).

   hep-phUkr.J.Phys.(2019)·1 citation
8. 08*

   Corrections to the Elastic Proton-Proton Analyzing Power Parametrization at High Energies

   A.A. Poblaguev🇺🇸

   The HJET Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) polarimeter was designed to measure the absolute polarization of the proton beams at the Relativistic Heavy Ion Collider. In these measurements, the small scattering angle elastic $pp$ single $A_N(t)$ and double $A_{NN}(t)$ spin analyzing powers can be precisely determined. The experimental accuracy achieved at HJET requires corrections to the $A_N(t)$ parametrization, conventionally used for such studies. In this paper we evaluate the corrections to the analyzing powers due to (i) the differences between the electromagnetic and hadronic form factors and (ii) the $m_p^2/s$ terms in the elastic spin-flip $pp$ electromagnetic amplitude. The corresponding alterations of the evaluated hadronic spin-flip amplitudes are about the same as the experimental uncertainties of the HJET measurements. The proposed corrections may have implications for the elastic $pp$ forward real-to-imaginary amplitude ratios $\rho$ determined in unpolarized $pp$ experiments.

   hep-phPRD(2019)·12 citations
9. 09*

   Same-sign Charged Higgs Pair Production in bosonic decay channels at the HL-LHC and HE-LHC

   Abdesslam Arhrib🇲🇦 · Kingman Cheung🇹🇼 · Chih-Ting Lu🇰🇷

   Same-sign charged Higgs pair production via vector-boson scattering is a useful probe of the mass spectrum among the heavier scalar, pseudoscalar, and charged Higgs bosons in two-Higgs-doublet models. It has been shown that the production cross section scales as the square of the mass difference $\Delta m=(m_{H^0}-m_{A^0})$ in the alignment limit $(\cos (\beta -\alpha )=0)$. We study the potential measurement of this same-sign charged Higgs pair production at the high-luminosity LHC (HL-LHC) and the proposed 27 TeV $pp$ collider, with emphasis in the decay channel $H^{\pm }{H}^{\pm }\to (W^{\pm }{A}^0)(W^{\pm }{A}^0)$, which is in general the dominant mode when the charged Higgs mass is above the $W^{\pm }{A}^0$ threshold. We also examine the current allowed parameter space taking into account the theoretical constraints on the model, the electroweak precision measurements, $B$ decays, and direct searches in the $H^{\pm }\to {\tau }^{\pm }{\nu }_{\tau }$ and $H^{\pm }\to W^{\pm }{A}^0\to ({\ell }^{\pm }{\nu }_{\ell })(\mu \mu )$.

   hep-phPRD(2020)·18 citations
10. 10*

    Effective Theory Approach to New Physics with Flavour: General Framework and a Leptoquark Example

    Marzia Bordone🇩🇪 · Oscar Catà🇩🇪 · Thorsten Feldmann🇩🇪

    Extending the Standard Model with higher-dimensional operators in an effective-field-theory (EFT) approach provides a systematic framework to study new-physics (NP) effects from a bottom-up perspective, as long as the NP scale is sufficiently large compared to the energies probed in the experimental observables. However, when taking into account the different quark and lepton flavours, the number of free parameters increases dramatically, which makes generic studies of the NP flavour structure infeasible. In this paper, we address this issue in view of the recently observed "flavour anomalies" in $B$-meson decays, which we take as a motivation to develop a general framework that allows us to systematically reduce the number of flavour parameters in the EFT. This framework can be easily used in global fits to flavour observables at Belle II and LHCb as well as in analyses of flavour-dependent collider signatures at the LHC. Our formalism represents an extension of the well-known minimal-flavour-violation approach, and uses Froggatt-Nielsen charges to define the flavour power-counting. As a relevant illustration of the formalism, we apply it to the flavour structures which could be induced by a $U_1$ vector leptoquark, which represents one of the possible explanations for the recent hints of flavour non-universality in semileptonic $B$-decays. We study the phenomenological viability of this specific framework performing a fit to low-energy flavour observables.

    hep-phJHEP(2020)·65 citations
11. 11*

    Phenomenological Advantages of the Normal Neutrino Mass Ordering

    Shao-Feng Ge🇨🇳 · Jing-yu Zhu🇨🇳

    The preference of the normal neutrino mass ordering from the recent cosmological constraint and the global fit of neutrino oscillation experiments does not seem like a wise choice at first glance since it obscures the neutrinoless double beta decay and hence the Majorana nature of neutrinos. Contrary to this naive expectation, we point out that the actual situation is the opposite. The normal neutrino mass ordering opens the possibility of excluding the higher solar octant and simultaneously measuring the two Majorana CP phases in future $0\nu 2\beta$ experiments. Especially, the funnel region will completely disappear if the solar mixing angle takes the higher octant. The combined precision measurement by the JUNO and Daya Bay experiments can significantly reduce the uncertainty in excluding the higher octant. With a typical $\mathcal{O}(\text{mbox}meV)$ sensitivity on the effective mass $|m_{ee}^{}|$, the neutrinoless double beta decay experiment can tell if the funnel region really exists and hence exclude the higher solar octant. With the sensitivity further improved to sub-meV, the two Majorana CP phases can be simultaneously determined. Thus, the normal neutrino mass ordering clearly shows phenomenological advantages over the inverted one.

    hep-phhep-exCPC(2020)·14 citations
12. 12*

    Properties of excited charmed-bottom mesons

    Ishrat Asghar🇵🇰 · Faisal Akram🇵🇰 · Bilal Masud🇵🇰 · M. Atif Sultan🇵🇰

    We calculate the spectrum of $B_c$ mesons using a non-relativistic quark potential model. Using the calculated wave functions, we compute the radiative widths of $B_c$ excited states. The strong decay widths are calculated in a modified ${}^3{P}_0$ model, assuming harmonic oscillator wave functions. The hadronic transition rates of $B_c$ mesons are calculated using the Kuang-Yan approach. These results are used to determine branching ratios of possible decay channels of several $B_c$ excited states. Calculated branching ratios are then combined with production cross section of $B_c$ states at the LHC to suggest strategies to find missing excited states of $B_c$ mesons.

    hep-phPRD(2019)·27 citations
13. 13*

    A Study of Power Suppressed Contributions in $J/\psi \to p\bar{p}$ Decay

    Nikolay Kivel🇷🇺

    The power suppressed amplitude which describes the Pauli (${\sigma }^{\mu \nu }$) coupling in the $J/\psi \to p\bar{p}$ decay is calculated within the effective field theory framework. It is shown that at the leading-order approximation this contribution is factorisable and the overlap with the hadronic final state can be described by collinear matrix elements. The obtained contribution depends on the nucleon light-cone distribution amplitudes of twist-3 and twist-4. This result is used for a qualitative phenomenological analysis of existing data for $J/\psi \to p\bar{p}$ decay: branching ratio and the angular distribution in the cross section $e^{+}{e}^{-}\to J/\psi \to p\bar{p}$.

    hep-phEPJA(2020)·9 citations
14. 14*

    Probing Unification With Precision Higgs Physics

    Sibo Zheng🇨🇳

    We propose a novel approach of probing grand unification through precise measurements on the Higgs Yukawa couplings at the LHC. This idea is well motivated by the appearance of effective operators not suppressed by the mass scale of unification $M_{\mathrm{U}}$ in realistic models of unification with the minimal structure of Yukawa sector. Such operators modify the Higgs Yukawa couplings in correlated patterns at scale $M_{\mathrm{U}}$ that hold up to higher-order corrections. The coherences reveal a feature that, the deviation of tau Yukawa coupling relative to its standard model value at the weak scale is the largest one among the third-generation Yukawa couplings. This feature, if verified by the future LHC, can serve as a hint of unification.

    hep-phhep-exhep-thPRD(2020)·0 citations
15. 15*

    Axial-vector exchange contribution to the hadronic light-by-light piece of the muon anomalous magnetic moment

    Pablo Roig🇲🇽 · Pablo Sanchez-Puertas🇪🇸

    In this work we study the axial contributions to the hadronic light-by-light piece of the muon anomalous magnetic moment using the framework of resonance chiral theory. As a result, we obtain $a_{\mu }^{\text{HLbL};A}=\left(0.8_{-0.1}^{+3.5}\right)\cdot 10^{-11}$, that might suggest a smaller value than most recent calculations, underlining the need of future work along this direction. In particular, we find that our results depend critically on the asymptotic behavior of the form factors, and as such, emphasizes the relevance of future experiments for large photon virtualities. In addition, we present general results regarding the involved axial form factors description, comprehensively examining (and relating) the current approaches, that shall be of general interest.

    hep-phPRD(2020)·183 citations
16. 16*

    The transverse nucleon single-spin asymmetry for the semi-inclusive production of photons in lepton-nucleon scattering

    Weeam S. Albaltan🇺🇸 · Alexei Prokudin🇺🇸 · Marc Schlegel🇺🇸

    We study the semi-inclusive production of real, high-$p_T$, isolated photons in unpolarized and polarized lepton-proton collisions, $\ell p\to \ell \gamma X$. In particular we analyze the transverse nucleon single-spin asymmetry within the collinear twist-3 formalism in perturbative QCD to leading order (LO) accuracy. We find that this spin asymmetry is generated by twist-3 dynamical quark-gluon-quark ($qgq$) correlations in the nucleon through the so-called soft-fermion and hard pole contributions. Hence, this process unprecedentedly allows for a point-by-point scan of the support of the dynamical $qgq$ twist-3 matrix elements $F_{FT}(x,x^{\prime })$ and $G_{FT}(x,x^{\prime })$ in lepton-nucleon scattering experiments.

    hep-phhep-exPLB(2020)·6 citations
17. 17*

    MADHAT: Model-Agnostic Dark Halo Analysis Tool

    Kimberly K. Boddy🇺🇸 · Stephen Hill🇺🇸 · Jason Kumar🇺🇸 · Pearl Sandick🇺🇸 · Barmak Shams Es Haghi🇺🇸

    We present the Model-Agnostic Dark Halo Analysis Tool (MADHAT), a numerical tool which implements a Fermi-LAT data-driven, model-independent analysis of gamma-ray emission from dwarf satellite galaxies and dwarf galaxy candidates due to dark matter annihilation, dark matter decay, or other nonstandard or unknown astrophysics. This tool efficiently provides statistical upper bounds on the number of observed photons in excess of the number expected, based on empirical determinations of foregrounds and backgrounds, using a stacked analysis of any selected set of dwarf targets. It also calculates the resulting bounds on the properties of dark matter under any assumptions the user makes regarding dark sector particle physics or astrophysics. As an application, we determine new bounds on Sommerfeld-enhanced dark matter annihilation in a set of eight dwarfs. MADHAT v1.0 includes 58 dwarfs and dwarf candidate targets, and we discuss future planned developments. MADHAT is available and will be maintained at https://github.com/MADHATdm

    hep-phastro-ph.HEComput.Phys.Commun.(2021)·20 citations
18. 18*

    Investigating saturation effects in ultraperipheral collisions at the LHC with the color dipole model

    Bharath Sambasivam🇺🇸 · Tobias Toll🇮🇳 · Thomas Ullrich🇺🇸

    We investigate saturation effects in $ep$ scattering as well as in ultraperipheral $p$A and AA collisions at small $x$ with four variants of the impact parameter dependent color dipole model: with and without gluon saturation and with and without a novel mechanism that suppresses unphysical dipole radii above the confinement scale, a problem not addressed by most implementations. We show that $ep$ scattering at HERA can be very well described by any of the four variants. When going from $ep$ to $e$A scattering, saturation effects are expected to increase as $\sim$A${}^{1/3}$. In lieu of an electron-ion collider, we confront the different versions of the dipole model with data recorded in ultraperipheral collisions at the LHC in order to estimate the sensitivity of the data to gluon saturation in the target nuclei. We find that ultraperipheral PbPb collisions indicate strong saturation effects while $p$Pb collisions turn out to not have any discriminating power to distinguish saturation from non-saturation scenarios.

    hep-phnucl-exnucl-thPLB(2020)·41 citations
19. 19*

    On the shape of the $\bar{d}-\bar{u}$ asymmetry

    A. Accardi · C.E. Keppel · S. Li · W. Melnitchouk · J.F. Owens

    Using data from a recent reanalysis of neutron structure functions extracted from inclusive proton and deuteron deep-inelastic scattering (DIS), we re-examine the constraints on the shape of the $\bar{d}-\bar{u}$ asymmetry in the proton at large parton momentum fractions $x$. A global analysis of the proton-neutron structure function difference from BCDMS, NMC, SLAC and Jefferson Lab DIS measurements, and of Fermilab Drell-Yan lepton-pair production cross sections, suggests that existing data can be well described with $\bar{d}>\bar{u}$ for all values of $x$ currently accessible. We compare the shape of the fitted $\bar{d}-\bar{u}$ distributions with expectations from nonperturbative models based on chiral symmetry breaking, which can be tested by upcoming Drell-Yan data from the SeaQuest experiment at larger values of $x$.

    hep-phhep-exnucl-thPLB(2020)·10 citations
20. 20*

    eV-scale sterile neutrinos from an extra dimension

    Shinsuke Kawai🇰🇷 · Nobuchika Okada🇺🇸

    Motivated by the short-baseline neutrino oscillation anomalies that suggest the existence of sterile neutrinos at the eV scale, we construct a scenario of a seesaw mechanism for 3+1 light neutrinos implemented by warped compactification of an extra dimension. As the seesaw mechanism necessitates at least two right-handed neutrinos at mass scales much larger than eV, incorporating an eV-scale sterile neutrino into a seesaw entails large mass hierarchies among the singlet neutrinos. We show that such hierarchies can be naturally explained by moderate fluctuations of the five-dimensional fermion mass parameters.

    hep-phhep-thPRD(2019)·4 citations
21. 21*

    Dirac neutrinos from Peccei-Quinn symmetry: a fresh look at the axion

    Eduardo Peinado🇲🇽 · Mario Reig🇪🇸 · Rahul Srivastava🇪🇸 · Jose W. F. Valle🇪🇸

    We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a type I Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.

    hep-phastro-ph.COhep-exhep-thMod.Phys.Lett.A(2020)·38 citations
22. 22*

    Consistent QFT description of non-standard neutrino interactions

    Adam Falkowski🇫🇷 · Martín González-Alonso🇪🇸 · Zahra Tabrizi🇧🇷

    Neutrino oscillations are precision probes of new physics beyond the Standard Model. Apart from neutrino masses and mixings, they are also sensitive to possible deviations of low-energy interactions between quarks and leptons from the Standard Model predictions. In this paper we develop a systematic description of such non-standard interactions (NSI) in oscillation experiments within the quantum field theory framework. We calculate the event rate and oscillation probability in the presence of general NSI, starting from the effective field theory (EFT) in which new physics modifies the flavor or Lorentz structure of charged-current interactions between leptons and quarks. We also provide the matching between the EFT Wilson coefficients and the widely used simplified quantum-mechanical approach, where new physics is encoded in a set of production and detection NSI parameters. Finally, we discuss the consistency conditions for the standard NSI approach to correctly reproduce the quantum field theory result.

    hep-phhep-thJHEP(2020)·45 citations
23. 23*

    Light- and strange-quark mass dependence of the $\rho (770)$ meson properties

    R. Molina🇧🇷 · J. Ruiz de Elvira🇨🇭

    From an analysis of recent ($I=J=1$)-$\pi \pi$-phase-shift and pseudoscalar-meson decay-constant lattice data on two distinct chiral trajectories, where either the sum of the up, down and strange quark masses, or the mass of the strange quark is kept fixed, we extract the light and strange quark mass dependence of the rho meson parameters, and make predictions of those on chiral trajectories which involve lighter masses than the physical strange quark mass. We find that the mass of the rho meson can get as light as $700$ MeV for strange quark mass zero at physical pion masses. While the ratio of the couplings to the $\pi \pi$ and $K\bar{K}$ channels is equal to $\sqrt{2}$ at the SU(3) symmetric chiral trajectory.

    ↳ hep-lathep-ph0 citations
24. 24*

    Addressing $\gamma$-ray emissions from dark matter annihilations in 45 milky way satellite galaxies and in extragalactic sources with particle dark matter models

    Ashadul Halder🇮🇳 · Shibaji Banerjee🇮🇳 · Madhurima Pandey🇮🇳 · Debasish Majumdar🇮🇳

    The mass to luminosity ratio of the dwarf satellite galaxies in the Milky Way suggests that these dwarf galaxies may contain substantial dark matter. The dark matter at the dense region such as within or at the vicinity of the centres of these dwarf galaxies may undergo the process of self annihilation and produce $\gamma$-rays as the end product. The satellite borne $\gamma$-ray telescope such as Fermi-LAT reported the detection of $\gamma$-rays from around 45 Dwarf Spheroidals (dSphs) of Milky Way. In this work, we consider particle dark matter models described in the literature and after studying their phenomenologies, we calculate the $\gamma$-ray fluxes from the self annihilation of the dark matter within the framework of these models in case of each of these 45 dSphs. we then compare the computed results with the observational upper bounds for $\gamma$-ray flux reported by Fermi-LAT and Dark Energy Survey (DES) for each of the 45 dSphs. The fluxes are calculated by adopting different dark matter density profiles. We then extend similar analysis for the observational upper bounds given by Fermi-LAT for the continuum $\gamma$-ray fluxes originating from extragalactic sources.

    ↳ astro-ph.COhep-phMNRAS(2020)·7 citations
25. 25*

    Bridging the Chiral symmetry and Confinement with Singularity

    Yoon-Seok Choun🇰🇷 · Sang-Jin Sin🇰🇷

    We consider a holographic quark model where the confinement is a consequence of the quark condensate. Surprisingly, the equation of motion of our holographic model can be mapped to the old spin-less bag model. Both models correctly reproduce the linear Regge trajectory of hadrons for zero quark mass. For the case of non-zero quark mass, the model lead us to Heun's equation. The mass term is precisely the origin of the higher singularity, which changes the system behavior drastically. Our result can shed some light on why the chiral transition is so close to the confinement transition. In the massive case, the Schroedinger equation is exactly solvable, but only if a surprising new quantization condition, additional to the energy quantization, is applied.

    ↳ hep-thhep-phnucl-thPLB(2020)·4 citations
26. 26*

    Joint constraint on primordial gravitational waves and polarization rotation angle with current CMB polarization data

    Hua Zhai🇨🇳 · Si-Yu Li🇨🇳 · Mingzhe Li🇨🇳 · Xinmin Zhang🇨🇳

    Cosmological CPT violation will rotate the polarized direction of CMB photons, convert partial CMB E mode into B mode and vice versa. It will generate non-zero EB, TB spectra and change the EE, BB, TE spectra. This phenomenon gives us a way to detect the CPT-violation signature from CMB observations, and also provides a new mechanism to produce B mode polarization. In this paper, we perform a global analysis on tensor-to-scalar ratio $r$ and polarization rotation angles based on current CMB datasets with both low $\ell$ (Planck, BICEP2/Keck Array) and high $\ell$ (POLARBEAR, SPTpol, ACTPol). Benefited from the high precision of CMB data, we obtain the isotropic rotation angle $\bar{\alpha }=-0.01^{\circ }\pm 0.37^{\circ }$ at 68% C.L., the variance of the anisotropic rotation angles $C^{\alpha }(0)<0.0032{\mathrm{rad}}^2$, the scale invariant power spectrum $D_{\ell \in [2,350]}^{\alpha \alpha }<4.71\times 10^{-5}{\mathrm{rad}}^2$ and $r<0.057$ at 95% C.L.. Our result shows that with the polarization rotation effect, the 95% upper limit on $r$ gets tightened by 17%.

    ↳ astro-ph.COhep-phhep-thPLB(2020)·7 citations
27. 27*

    Instability of Higgs Vacuum via String Cloud

    Issei Koga🇯🇵 · Sachiko Kuroyanagi🇯🇵 · Yutaka Ookouchi🇯🇵

    We study the instability of the Higgs vacuum caused by a cloud of strings. By catalysis, the decay rate of the vacuum is highly enhanced and, when the energy density of the cloud is larger than the critical value, a semi-classical vacuum decay occurs. We also discuss the relation between the string cloud and observational constraints on the cosmic strings from the viewpoint of the catalysis, which are converted into bounds on the parameters of the Higgs potential.

    ↳ hep-thhep-phPLB(2020)·11 citations
28. 28*

    Hunt for dark subhalos in the galactic stellar field using computer vision

    Mihael Petac🇮🇹

    The lack of tangible evidence for non-gravitational interactions between dark and visible sectors drives the need for exploring new avenues of inferring dark matter properties through purely gravitational probes. In particular, addressing small-scale distribution of dark matter could lead to valuable new insights into its particle nature, either confirming predictions of the collisionless cold dark matter hypothesis or favouring models with suppressed small-scale matter power spectrum. In this work we propose a novel machine learning approach for constraining the abundance of galactic dark matter subhaloes through the analysis of Milky Way's stellar field that has been only recently mapped with sufficient coverage thanks to the Gaia mission. Our method is based on convolutional neural networks which represent a powerful tool for identifying characteristic perturbations in spatial maps of stellar number density and velocity distribution moments. For generating the training data we develop a robust and computationally efficient algorithm, capable of generating mock stellar fields from an arbitrary underlying phase-space distribution of stars. By preforming a preliminary study of the outlined approach on synthetic datasets we demonstrate that sensitivities down to (or even below) $10^8{M}_{\odot }$ could be reached. Furthermore, our results show that the accuracy of the advocated technique crucially depends on the kinematic properties of mapped stars and could be further improved by applying it to abundant stellar populations with particularly low velocity dispersion, such as the galactic thin disc stars.

    ↳ astro-ph.GAhep-ph5 citations
29. 29*

    Diphoton elastic scattering in UPC at smaller $W_{\gamma \gamma }$

    Antoni Szczurek🇵🇱

    We present a study of photon-photon scattering for $W_{\gamma \gamma }<5$ GeV. We extend earlier calculations of this cross section for $W_{\gamma \gamma }>$ 5 GeV into the low mass range where photoproduction of the pseudoscalar mesons $\eta$(548), ${\eta }^{{}^{\prime }}(958)$ and other mesonic resonances contribute to the two-photon final states. We consider the dominant background of the two photon final state which arises from $\gamma \gamma$ decays of photoproduced ${\pi }^0{\pi }^0$-pairs. We discuss how to reduce the background by imposing cuts on different kinematical variables. We present results for ALICE and LHCb kinematics.

    ↳ nucl-thhep-phFrascati Phys.Ser.(2019)·0 citations
30. 30*

    Scalar-field dark energy nonminimally and kinetically coupled to dark matter

    Ryotaro Kase🇯🇵 · Shinji Tsujikawa🇯🇵

    We provide a general framework for studying the dark energy cosmology in which a scalar field $\varphi$ is nonminimally and kinetically coupled to Cold Dark Matter (CDM). The scalar-graviton sector is described by the action of Horndeski theories with the speed of gravitational waves equivalent to that of light, whereas CDM is treated as a perfect fluid given by a Schutz-Sorkin action. We consider two interacting Lagrangians of the forms $f_1(\varphi ,X){\rho }_c(n_c)$ and $f_2(n_c,\varphi ,X)J_c^{\mu }{\partial }_{\mu }\varphi$, where $X=-{\partial }^{\mu }\varphi {\partial }_{\mu }\varphi /2$, ${\rho }_c$ and $n_c$ are the energy density and number density of CDM respectively, and $J_c^{\mu }$ is a vector field related to the CDM four velocity. We derive the scalar perturbation equations of motion without choosing any special gauges and identify conditions for the absence of ghosts and Laplacian instabilities on scales deep inside the sound horizon. Applying a quasi-static approximation in a gauge-invariant manner, we also obtain the effective gravitational couplings felt by CDM and baryons for the modes relevant to the linear growth of large-scale structures. In particular, the $n_c$ dependence in the coupling $f_2$ gives rise to an interesting possibility for realizing the gravitational coupling with CDM weaker than the Newton gravitational constant $G$.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·71 citations
31. 31*

    Do charged pions condense in a magnetic field with rotation?

    Hao-Lei Chen🇨🇳 · Xu-Guang Huang🇨🇳 · Kazuya Mameda🇨🇳

    We revisit the condensation scenario of charged pions in external magnetic field and rotation, which was first considered by Y. Liu and I. Zahed. Based on the Ginzburg-Landau analysis of the Nambu--Jona-Lasinio model, we find that the charged-pion condensation takes place only when both a strong coupling constant and negatively large baryon chemical potential are applied. Besides, our numerical calculation shows that the chiral restoration induced by the interplay between magnetic field and rotation (i.e., the rotational magnetic inhibition) interrupts the formation of the charged-pion condensate. This suggests that the analysis of such condensation requires a careful treatment of the inner structure of pions, which was not taken into account before. We also discuss the underlying physical mechanism of our finding and the indication of charged-rho condensation.

    ↳ nucl-thhep-phJHEP(2024)·41 citations
32. 32*

    Rotation induced charged pion condensation in a strong magnetic field: A Nambu--Jona-Lasino model study

    Gaoqing Cao🇨🇳 · Lianyi He🇨🇳

    We investigate the possibility of charged pion condensation in the presence of parallel rotation and magnetic field within the Nambu--Jona-Lasinio model with quarks as the fundamental degrees of freedom. Previous study based on non-interacting Klein-Gordon theory for pions showed that the charged pions will undergo Bose-Einstein condensation under this circumstance [Y. Liu and I. Zahed, Phys. Rev. Lett. $120$, 032001 (2018)]. In this work, we take into account the internal quark structures of charged pions self-consistently through quark polarization loops in an interacting theory, i.e., the Nambu--Jona-Lasino model. The stability of the system is explored against the formation of a nonzero expectation value of the composite charged pion field $\bar{u}i{\gamma }_{5}d$. We find that two competing effects are induced by the rotation: the isospin enhancement which favors charged pion condensation and the spin breaking which disfavors the condensation. For a strong magnetic field ($\sqrt{eB}\sim 1\mathrm{GeV}$) and system size of a few fermi, the isospin enhancement effect is stronger than the spin breaking one, and the charged pion condensation becomes energetically favored beyond a critical angular velocity of a few MeV.

    ↳ nucl-thhep-phhep-thPRD(2019)·36 citations
33. 33*

    Possible lightest $\Xi$ Hypernucleus with Modern $\Xi N$ Interactions

    E. Hiyama🇯🇵 · K. Sasaki🇯🇵 · T. Miyamoto🇯🇵 · T. Doi🇯🇵 · T. Hatsuda🇯🇵 · Y. Yamamoto🇯🇵 · Th. A. Rijken🇳🇱

    Experimental evidence exists that the $\Xi$-nucleus interaction is attractive. We search for $NN\Xi$ and $NNN\Xi$ bound systems on the basis of the AV8 $NN$ potential combined with either a phenomenological Nijmegen $\Xi N$ potential or a first principles HAL QCD $\Xi N$ potential. The binding energies of the three-body and four-body systems (below the $d+\Xi$ and ${}^3\mathrm{H}$/${}^3\mathrm{He}+\Xi$ thresholds, respectively) are calculated by a high precision variational approach, the Gaussian Expansion Method. Although the two $\Xi N$ potentials have significantly different isospin ($T$) and spin ($S$) dependence, the $NNN\Xi$ system with quantum numbers $(T=0,J^{\pi }=1^{+}$) appears to be bound (one deep for Nijmegen and one shallow for HAL QCD) below the ${}^3\mathrm{H}$/${}^3\mathrm{He}+\Xi$ threshold. Experimental implications for such a state are discussed.

    ↳ nucl-thhep-lathep-phnucl-exPRL(2020)·61 citations
34. 34*

    Hubble-rate-dependent Dark Energy in Brans-Dicke Cosmology

    E. Karimkhani🇮🇷 · A.Khodam-Mohammadi🇮🇷

    Three general cases of dynamical interacting dark energy models ($\mathcal{D}$-class) are investigated in the context of Brans-Dicke cosmology. Some of important cosmological quantities are calculated for every cases as a function of redshift parameter. The most important part of this paper deals with fitting models with two different expansion history: (SNIa+BAO${}_A$+$Om{h}^2$ and SNIa+BAO${}_A$+H(z)) and with two different sets of data for Hubble parameter. This provides a remarkable feature to could analytically see the effects of each analyzes and each data sets on final results. The best fitted values of parameters according to these analyzes and data points, ${\chi }_{tot}^2/dof$, AIC and BIC are reported. By these diagnostic tools we found that some of these models have no chance against $\Lambda$CDM, even without need to study the structure formation, and could be ruled out. While some (e.g. $\mathcal{B}\mathcal{D}-\mathcal{D}C2$ and $\mathcal{B}\mathcal{D}-\mathcal{D}{A}^{\ast }$) render the best fit quality,i.e. the value of AIC and BIC and figures show that they fit perfectly with overall data and reveals a strong evidence in favor of these two models against $\Lambda$CDM.

    ↳ astro-ph.COgr-qchep-phhep-thAstrophys.Space Sci.(2019)·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.