Mon·Jan 8, 2018Monday·January 8, 2018

1. 01*

   Non-Standard Neutrino Interactions : Obviating Oscillation Experiments

   Debajyoti Choudhury🇮🇳 · Kirtiman Ghosh🇮🇳 · Saurabh Niyogi🇮🇳

   Searching for non-standard neutrino interactions, as a means for discovering physics beyond the Standard Model, has one of the key goals of dedicated neutrino experiments, current and future. We demonstrate here that much of the parameter space accessible to such experiments is already ruled out by the RUN II data of the Large Hadron Collider experiment.

   hep-phhep-exPLB(2018)·24 citations
2. 02*

   Unintegrated dipole gluon distribution at small transverse momentum

   Raktim Abir🇮🇳 · Khatiza Banu🇿🇦 · Trambak Bhattacharyya🇿🇦 · Mariyah Siddiqah🇮🇳 · Nahid Vasim🇿🇦

   We derive analytical results for unintegrated color dipole gluon distribution function at small transverse momentum. By Fourier transforming the $S$-matrix for large dipoles we derive the results in the form of a series of Bells polynomials. Interestingly, when resumming the series in leading log accuracy, the results showing up striking similarity with the Sudakov form factor with role play of coupling is being done by a constant that stems from the saddle point condition along the saturation line.

   hep-phhep-thnucl-thPRD(2018)·9 citations
3. 03*

   The implication of gauge-Higgs unification to the hierarchical fermion masses

   C.S. Lim🇯🇵

   The observed hierarchical charged fermion masses of three generations seem to imply that these masses are originally universal for three generations and then get exponential suppression with "quantized exponents" by some mechanism. We argue that such remarkable feature of hierarchical fermion mass spectrum may be naturally understood in the scenario of gauge-Higgs unification, where the universality of fermion masses is guaranteed by the fact that Higgs boson is originally gauge boson in this scenario and also the quantized exponents may be attributed to the well-known quantization condition of magnetic charge of the magnetic monopole placed inside the torus, as the extra dimensional space. Because of the presence of the magnetic monopole, we get a chiral theory and multiple Kaluza-Klein zero modes even if we introduce only a single 6-dimensional Weyl fermion. We present two types of three generation model, which succeed to realize the remarkable hierarchical mass spectrum.

   hep-phhep-thPTEP(2018)·9 citations
4. 04*

   $\psi (2S)$ photoproduction in high energy nuclear collisions

   Baoyi Chen🇨🇳 · Carsten Greiner🇩🇪 · Wei Shi · Wangmei Zha🇨🇳 · Pengfei Zhuang🇨🇳

   We study coherent photoproduction of ${\psi }^{\prime }$ and the subsequent suppression in high energy nuclear collisions. The hot medium effect on charmonium photoproduction is controlled by the competition between the fireball size and nuclear size. When the former is smaller than the later, the photoproduction is only slightly affected by the hot medium. We calculate the yield ratio of ${\psi }^{\prime }$ to $J/\psi$ in semi-central Pb-Pb collisions at LHC energy, while the high $p_T$ limit is characterized by the fireball, its value in low $p_T$ limit can still reach the significant enhancement by photoproduction.

   hep-phnucl-th5 citations
5. 05*

   Proton structure in a light-front quark-diquark model: Collins asymmetry

   Tanmay Maji🇮🇳 · Dipankar Chakrabarti🇮🇳

   We present model predictions of Collins asymmetries for proton in the SIDIS process for ${\pi }^{+}$ and ${\pi }^{-}$ channels. We use a recently proposed light-front quark-diquark model for proton with the light-front wave functions predicted in soft-wall AdS/QCD. The model predictions are compared with the HERMES and COMPASS data.

   hep-phPoS(2018)·0 citations
6. 06*

   Parton distribution functions of proton in a light-front quark-diquark model

   Tanmay Maji🇮🇳 · Dipankar Chakrabarti🇮🇳

   We present the parton distribution functions (PDFs) for un- polarised, longitudinally polarized and transversely polarized quarks in a proton using the light-front quark diquark model. We also present the scale evolution of PDFs and calculate axial charge and tecsor charge for $u$ and $d$ quarks at a scale of experimental findings.

   hep-phSpringer Proc.Phys.(2018)·2 citations
7. 07*

   RG-improvement of the effective action with multiple mass scales

   Satoshi Iso🇯🇵 · Kiyoharu Kawana🇯🇵

   Improving the effective action by the renormalization group (RG) with several mass scales is an important problem in quantum field theories. A method based on the decoupling theorem was proposed in \cite{Bando:1992wy} and systematically improved \cite{Casas:1998cf} to take threshold effects into account. In this paper, we apply the method to the Higgs-Yukawa model, including wave-function renormalizations, and to a model with two real scalar fields $(\phi ,h)$. In the Higgs-Yukawa model, even at one-loop level, Feynman diagrams contain propagators with different mass scales and decoupling scales must be chosen appropriately to absorb threshold corrections. On the other hand, in the two-scalar model, the mass matrix of the scalar fields is a function of their field values $(\phi ,h)$ and the resultant running couplings obey different RGEs on a different point of the field space. By solving the RGEs, we can obtain the RG improved effective action in the whole region of the scalar fields.

   hep-phhep-thJHEP(2018)·10 citations
8. 08*

   Once More on Coulomb-Nuclear Interference

   Vladimir A. Petrov🇷🇺

   This is a critical reconsideration of the standard way of account for Coulomb-nuclear interference in elastic scattering amplitude.

   hep-phEPJC(2018)·30 citations
9. 09*

   Access to improve the muon mass and magnetic moment anomaly via the bound-muon $g$ factor

   B. Sikora🇵🇱 · H. Cakir🇩🇪 · N. Michel🇩🇪 · V. Debierre🇩🇪 · N. S. Oreshkina🇩🇪 · N. A. Belov🇩🇪 · V. A. Yerokhin🇩🇪 · C. H. Keitel🇩🇪 · Z. Harman🇩🇪

   A theoretical description of the $g$ factor of a muon bound in a nuclear potential is presented. One-loop self-energy and multi-loop vacuum polarization corrections are calculated, taking into account the interaction with the binding potential exactly. Nuclear effects on the bound-muon $g$ factor are also evaluated. We put forward the measurement of the bound-muon $g$ factor via the continuous Stern-Gerlach effect as an independent means to determine the free muons magnetic moment anomaly and mass. The scheme presented enables to increase the accuracy of the mass by more than an order of magnitude.

   hep-phphysics.atom-phPRD(2018)·9 citations
10. 10*

    Is the gamma-ray emission around the Coma galaxy cluster a dark matter origin?

    Yun-Feng Liang🇨🇳 · Zi-Qing Xia🇨🇳 · Shao-Qiang Xi🇨🇳 · Shang Li🇨🇳 · Zhao-Qiang Shen🇨🇳 · Yi-Zhong Fan🇨🇳

    Recently, gamma-ray emission in the direction of Coma, with a TS value of $\sim 40$, has been reported. In this work we will discuss the possibility of such a residual emission coming from dark matter annihilation. Our results show that the gamma-ray emission within the Coma region is also spatially correlated to the mass distribution derived from weak gravitational lensing measurements very well. However the dark matter models are not supported by the spectral analysis results and constraints by observations of other targets. Thus we derive the upper limits of the dark matter annihilation cross section according to the observation of the Coma region.

    ↳ astro-ph.HEhep-ph4 citations
11. 11*

    Searching for spectral oscillations due to photon-axionlike particle conversion using the Fermi-LAT observations of bright supernova remnants

    Zi-Qing Xia🇨🇳 · Cun Zhang🇨🇳 · Yun-Feng Liang🇨🇳 · Lei Feng🇨🇳 · Qiang Yuan🇨🇳 · Yi-Zhong Fan🇨🇳 · Jian Wu🇨🇳

    Axionlike-particles (ALPs) are one promising type of dark matter candidate particle that may generate detectable effects on $\gamma$-ray spectra other than the canonical weakly interacting massive particles. In this work we search for such oscillation effects in the spectra of supernova remnants caused by the photon-ALP conversion, using the Fermi Large Area Telescope data. Three bright supernova remnants, IC443, W44, and W51C, are analyzed. The inclusion of photon-ALP oscillations yields an improved fit to the $\gamma$-ray spectrum of IC443, which gives a statistical significance of $4.2\sigma$ in favor of such spectral oscillation. However, the best-fit parameters of ALPs ($m_a=6.6\mathrm{neV}$, $g_{a\gamma }=13.4\times 10^{-11}{\mathrm{GeV}}^{-1}$) are in tension with the upper bound ($g_{a\gamma }<6.6\times 10^{-11}{\mathrm{GeV}}^{-1}$) set by the CAST experiment. It is difficult to explain the results using the systematic uncertainties of the flux measurements. We speculate that the "irregularity" displayed in the spectrum of IC443 may be due to the superposition of the emission from different parts of the remnant.

    ↳ astro-ph.HEhep-phPRD(2018)·40 citations
12. 12*

    Nambu--Jona-Lasinio model in a parallel electromagnetic field

    Lingxiao Wang🇨🇳 · Gaoqing Cao🇨🇳 · Xu-Guang Huang🇨🇳 · Pengfei Zhuang🇨🇳

    We explore the features of the $U_A(1)$ and chiral symmetry breaking of the Nambu--Jona-Lasinio model without the Kobayashi-Maskawa-'t Hooft determinant term in the presence of a parallel electromagnetic field. We show that the electromagnetic chiral anomaly can induce both finite neutral pion condensate and isospin-singlet pseudo-scalar $\eta$ condensate and thus modifies the chiral symmetry breaking pattern. In order to characterize the strength of the $U_A(1)$ symmetry breaking, we evaluate the susceptibility associated with the $U_A(1)$ charge. The result shows that the susceptibility contributed from the chiral anomaly is consistent with the behavior of the corresponding $\eta$ condensate. The spectra of the mesonic excitations are also studied.

    ↳ nucl-thhep-phhep-thPLB(2018)·20 citations
13. 13*

    A fresh look at the (non-)Abelian Landau-Khalatnikov-Fradkin transformations

    T. De Meerleer🇧🇪 · D. Dudal🇧🇪 · S. P. Sorella🇧🇷 · P. Dall'Olio🇲🇽 · A. Bashir🇲🇽

    The Landau-Khalatnikov-Fradkin transformations (LKFTs) allow to interpolate $n$-point functions between different gauges. We first offer an alternative derivation of these LKFTs for the gauge and fermions field in the Abelian (QED) case when working in the class of linear covariant gauges. Our derivation is based on the introduction of a gauge invariant transversal gauge field, which allows a natural generalization to the non-Abelian (QCD) case of the LKFTs. To our knowledge, within this rigorous formalism, this is the first construction of the LKFTs beyond QED. The renormalizability of our setup is guaranteed to all orders. We also offer a direct path integral derivation in the non-Abelian case, finding full consistency.

    ↳ hep-thhep-lathep-phPRD(2018)·20 citations
14. 14*

    Bulk Properties of the Matter Produced at Energies of the Beam Energy Scan Program

    Yu. B. Ivanov🇷🇺 · A. A. Soldatov🇷🇺

    Recent STAR data on the bulk observables in the energy range of the Beam-Energy Scan Program at the Relativistic Heavy-Ion Collider are analyzed within the model of the three-fluid dynamics (3FD). The simulations are performed with different equations of state (EoS). The purely hadronic EoS fails to reproduce the data. A good, though imperfect, overall reproduction of the data is found within the deconfinement scenarios. The crossover EoS turns out to be slightly preferable. For this reproduction a fairly strong baryon stopping in the quark-gluon phase is required. The 3FD model does not need two separate freeze-outs (i.e. kinetic and chemical ones) to describe the STAR data. A unified freeze-out is applied at all energies.

    ↳ nucl-thhep-phnucl-exPRC(2018)·15 citations
15. 15*

    Black hole perturbations in vector-tensor theories: The odd-mode analysis

    Ryotaro Kase🇯🇵 · Masato Minamitsuji🇵🇹 · Shinji Tsujikawa🇯🇵 · Ying-li Zhang🇯🇵

    In generalized Proca theories with vector-field derivative couplings, a bunch of hairy black hole solutions have been derived on a static and spherically symmetric background. In this paper, we formulate the odd-parity black hole perturbations in generalized Proca theories by expanding the corresponding action up to second order and investigate whether or not black holes with vector hair suffer ghost or Laplacian instabilities. We show that the models with cubic couplings $G_3(X)$, where $X=-A_{\mu }{A}^{\mu }/2$ with a vector field $A_{\mu }$, do not provide any additional stability condition as in General Relativity. On the other hand, the exact charged stealth Schwarzschild solution with a nonvanishing longitudinal vector component $A_1$, which originates from the coupling to the Einstein tensor $G^{\mu \nu }{A}_{\mu }{A}_{\nu }$ equivalent to the quartic coupling $G_4(X)$ containing a linear function of $X$, is unstable in the vicinity of the event horizon. The same instability problem also persists for hairy black holes arising from general quartic power-law couplings $G_4(X)\supset {\beta }_4{X}^n$ with the nonvanishing $A_1$, while the other branch with $A_1=0$ can be consistent with conditions for the absence of ghost and Laplacian instabilities. We also discuss the case of other exact and numerical black hole solutions associated with intrinsic vector-field derivative couplings and show that there exists a wide range of parameter spaces in which the solutions suffer neither ghost nor Laplacian instabilities against odd-parity perturbations.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2018)·42 citations
16. 16*

    Exotic energy injection with ExoCLASS: Application to the Higgs portal model and evaporating black holes

    Patrick Stöcker🇩🇪 · Michael Krämer🇩🇪 · Julien Lesgourgues🇩🇪 · Vivian Poulin🇺🇸

    We devise a new user-friendly tool interfaced with the Boltzmann code CLASS to deal with any kind of exotic electromagnetic energy injection in the universe and its impact on anisotropies of the Cosmic Microwave Background. It makes use of the results from standard electromagnetic cascade calculations develop in the context of WIMP annihilation, generalized to incorporate any injection history. We first validate it on a specific WIMP scenario, the Higgs Portal model, confirming that the standard effective on-the-spot treatment is accurate enough. We then analyze the more involved example of evaporating Primordial Black Holes (PBHs) with masses in the range $[3\times 10^{13},5\times 10^{16}]$g, for which the standard approximations break down. We derive robust CMB bounds on the relic density of evaporating PBHs, ruling out the possibility for PBHs with a monochromatic distribution of masses in the range $[3\times 10^{13},2.5\times 10^{16}]$g to represent all of the Dark Matter in our Universe. Remarkably, we confirm with an accurate study that the CMB bounds are several orders of magnitude stronger than those from the galactic gamma-ray background in the range $[3\times 10^{13},3\times 10^{14}]$g. A future CMB experiment like CORE+, or an experiment attempting at measuring the 21 cm signal from the Dark Ages could greatly improve the sensitivity to these models.

    ↳ astro-ph.COhep-phJCAP(2018)·127 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.