Mon·Jun 24, 2019Monday·June 24, 2019

1. 01*

   Fast Neutrino Flavor Conversion: Collective Motion vs. Decoherence

   Francesco Capozzi🇩🇪 · Georg Raffelt🇩🇪 · Tobias Stirner🇩🇪

   In an interacting neutrino gas, flavor coherence becomes dynamical and can propagate as a collective mode. In particular, tachyonic instabilities can appear, leading to "fast flavor conversion" that is independent of neutrino masses and mixing angles. On the other hand, without neutrino-neutrino interaction, a prepared wave packet of flavor coherence simply dissipates by kinematical decoherence of infinitely many non-collective modes. We reexamine the dispersion relation for fast flavor modes and show that for any wavenumber,there exists a continuum of non-collective modes besides a few discrete collective ones. So for any initial wave packet, both decoherence and collective motion occurs, although the latter typically dominates for a sufficiently dense gas. We derive explicit eigenfunctions for both collective and non-collective modes. If the angular mode distribution of electron-lepton number crosses between positive and negative values, two non-collective modes can merge to become a tachyonic collective mode. We explicitly calculate the interaction strength for this critical point. As a corollary we find that a single crossing always leads to a tachyonic instability. For an even number of crossings, no instability needs to occur.

   hep-phastro-ph.HEJCAP(2019)·62 citations
2. 02*

   Electroweak pseudo-observables and Z-boson form factors at two-loop accuracy

   Ievgen Dubovyk🇩🇪 · Ayres Freitas🇺🇸 · Janusz Gluza🇵🇱 · Tord Riemann🇵🇱 · Johann Usovitsch🇮🇪

   We present Standard Model predictions for the complete set of phenomenologically relevant electroweak precision pseudo-observables related to the Z-boson: the leptonic and bottom-quark effective weak mixing angles ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$, ${\sin }^2{\theta }_{\mathrm{eff}}^b$, the Z-boson partial decay widths ${\Gamma }_f$, where $f$ indicates any charged lepton, neutrino and quark flavor (except for the top quark), as well as the total Z decay width ${\Gamma }_Z$, the branching ratios $R_{\ell }$, $R_c$, $R_b$, and the hadronic cross section ${\sigma }_{\mathrm{had}}^0$. The input parameters are the masses $M_Z$, $M_H$ and $m_t$, and the couplings ${\alpha }_s$, $\alpha$. The scheme dependence due to the choice of $M_W$ or its alternative $G_{\mu }$ as a last input parameter is also discussed. Recent substantial technical progress in the calculation of Minkowskian massive higher-order Feynman integrals allows the calculation of the complete electroweak two-loop radiative corrections to all the observables mentioned. QCD contributions are included appropriately. Results are provided in terms of simple and convenient parameterization formulae whose coefficients have been determined from the full numerical multi-loop calculation. The size of the missing electroweak three-loop or QCD higher-order corrections is estimated. We briefly comment on the prospects for their calculation. Finally, direct predictions for the $Z\bar{f}f$ vector and axial-vector form-factors are given, including a discussion of separate order-by-order contributions.

   hep-phJHEP(2019)·78 citations
3. 03*

   Chiral magnetic effect in the hadronic phase

   Shota Imaki🇯🇵

   We study the chiral magnetic effect (CME) in the hadronic phase. The CME current involves pseudoscalar mesons to modify its functional form. This conclusion is independent of microscopic details. The strength of the CME current in the hadronic phase would decrease for two flavors.

   hep-phhep-thPRD(2020)·2 citations
4. 04*

   Anomalous Kolar Events and Dark Matter Decay in Dwarf Spheroidal Galaxies

   R. Thiru Senthil🇮🇳 · G. Rajasekaran🇮🇳

   Using the Fermi LAT data on the gamma ray emission from dwarf spheroidal galaxies, we get the upper bound on the probability of gamma rays from dark matter decay for the validity of explanation of the anomalous Kolar events as dark matter decay.

   hep-phastro-ph.HE0 citations
5. 05*

   Photo-production of Higgs Boson at the LHeC

   Ruibo Li🇨🇳 · Xiang Lv🇨🇳 · Bo-Wen Wang🇨🇳 · Kai Wang🇨🇳 · Tao Xu🇨🇳

   As one category of vector boson fusion, photo-production is one important production mechanism at $e$-$p$ colliders. A future $e$-$p$ collider -- Large Hadron-electron Collider (LHeC) has been discussed as a "Higgs factory" candidate where the Higgs boson produced via weak boson fusion (WBF) at the LHeC plays an important role in precision measurement of Yukawa couplings. On the other hand, a measurement of photo-production of the Higgs boson, if possible, might be complementary to the measurement of Higgs to di-photon partial decay width $\Gamma (h\to \gamma \gamma )$. In this paper, we study the possibility of measuring this production process at the LHeC with the help of the photon PDFs published in recent years. This process has a clean final state without additional colored particles in the detectable region other than the decay products of the Higgs. We compute the cross sections of all related processes and find that the production rate is at the same order as the neutral current WBF production of Higgs boson with missing forward jets. However, a detailed phenomenological study of various Higgs decay channels shows that even in the most promising semi-leptonic $WW$ channel, the feasibility of identifying such photo-production is negative due to an irreducible photo-production of $W^{+}{W}^{-}$.

   hep-phNPB(2020)·1 citation
6. 06*

   Double prompt $J/\psi$ hadroproduction in the parton Reggeization approach with high-energy resummation

   Zhi-Guo He🇩🇪 · Bernd A. Kniehl🇩🇪 · Maxim A. Nefedov🇷🇺 · Vladimir A. Saleev🇷🇺

   We study double prompt $J/\psi$ hadroproduction within the nonrelativistic-QCD factorization formalism adopting the parton Reggeization approach to treat initial-state radiation in a gauge invariant and infrared-safe way. We present first predictions for the cross section distributions in the transverse momenta of the subleading $J/\psi$ meson and the $J/\psi$ pair. Already at leading order in ${\alpha }_s$, these predictions as well as those for the total cross section and its distributions in the invariant mass $m_{\psi \psi }$ and the rapidity separation $|Y|$ of the $J/\psi$ pair nicely agree with recent ATLAS and CMS measurements, except for the large-$m_{\psi \psi }$ and large-$|Y|$ regions, where the predictions substantially undershoot the data. In the latter regions, BFKL resummation is shown to enhance the cross sections by up to a factor of two and so to improve the description of the data.

   hep-phhep-exPRL(2019)·44 citations
7. 07*

   $B_{s1}(5778)$ as a $B^{\ast }\bar{K}$ molecule in the Bethe-Salpeter equation approach

   Zhen-Yang Wang🇨🇳 · Jing-Juan Qi🇨🇳 · Qi-Xin Yu🇨🇳 · Xin-Heng Guo🇨🇳

   We interpret the $B_{s1}(5778)$ as an $S$-wave $B^{\ast }\bar{K}$ molecular state in the Bethe-Salpeter equation approach. In the ladder and instantaneous approximations, and with the kernel containing one-particle-exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) in the vertex, we find the bound state exists. We also study the decay widths of the decay $B_{s1}(5778)\to B_s^{\ast }\pi$ and the radiative decays $B_{s1}(5778)\to B_s\gamma$ and $B_{s1}(5778)\to B_s^{\ast }\gamma$, which will be instructive for the forthcoming experiments.

   hep-phPRD(2019)·4 citations
8. 08*

   Prediction of hidden charm strange molecular baryon states with heavy quark spin symmetry

   C. W. Xiao🇨🇳 · J. Nieves🇪🇸 · E. Oset🇪🇸

   We have studied the meson-baryon $S-$wave interaction, using coupled channels, in the isoscalar hidden-charm strange sector and $J^P=1/2^{-},3/2^{-}$ and $5/2^{-}$. We impose constraints of heavy quark spin symmetry in the interaction and obtain the non vanishing matrix elements from an extension of the local hidden gauge approach to the charm sector. The ultraviolet divergences are renormalized using the same meson-baryon-loops regulator previously employed in the non-strange hidden charm sector, where a good reproduction of the properties of the newly discovered pentaquark states is obtained. We obtain five states of $1/2^{-}$, four of $3/2^{-}$ and one of $5/2^{-}$, which could be compared in the near future with forthcoming LHCb experiments. The $5/2^{-}$, three of the $3/2^{-}$ and another three of the $1/2^{-}$ resonances are originated from isoscalar ${\bar{D}}^{(\ast )}{\Xi }_c^{\prime }$ and ${\bar{D}}^{(\ast )}{\Xi }_c^{\ast }$ interactions. They should be located just few MeV below the corresponding thresholds (4446, 4513, 4588 and 4655 MeV), and would be SU(3)-siblings of the isospin 1/2 ${\bar{D}}^{(\ast )}{\Sigma }_c^{(\ast )}$ quasi-bound states previously found, and that provided a robust theoretical description of the $P_c(4440)$, $P_c(4457)$ and $P_c(4312)$ LHCb exotic states. The another two $1/2^{-}$ and $3/2^{-}$ states obtained in this work are result of the ${\bar{D}}^{(\ast )}{\Xi }_c-D_s^{(\ast )}{\Lambda }_c$ coupled-channels isoscalar interaction, are significantly broader than the others, with widths of the order of 15 MeV, being ${\bar{D}}_s^{(\ast )}{\Lambda }_c$ the dominant decay channel.

   hep-phPLB(2019)·122 citations
9. 09*

   NNLO QCD$\oplus$QED corrections to Higgs production in bottom quark annihilation

   Ajjath A H🇮🇳 · Pulak Banerjee🇨🇭 · Amlan Chakraborty🇮🇳 · Prasanna K. Dhani🇮🇹 · Pooja Mukherjee🇮🇳 · Narayan Rana🇮🇹 · V. Ravindran🇮🇳

   We present next-to-next-to leading order (NNLO) quantum electrodynamics (QED) corrections to the production of the Higgs boson in bottom quark annihilation at the Large Hadron Collider (LHC) in the five flavor scheme. We have systematically included the NNLO corrections resulting from the interference of quantum chromodynamics (QCD) and QED interactions. We have investigated the infrared (IR) structure of the bottom quark form factor up to two loop level in QED and in QCD$\times$QED using K+G equation. We find that the IR poles in the form factor are controlled by the universal cusp, collinear and soft anomalous dimensions. In addition, we derive the QED as well as QCD$\times$QED contributions to soft distribution function as well as to the ultraviolet renormalization constant of the bottom Yukawa coupling up to second order in strong coupling and fine structure constant. Finally, we report our findings on the numerical impact of the NNLO results from QED and QCD$\times$QED at the LHC energies taking into account the dominant NNLO QCD corrections.

   hep-phPRD(2019)·38 citations
10. 10*

    Higher-order power corrections in a transverse-momentum cut for colour-singlet production at NLO

    Leandro Cieri🇮🇹 · Carlo Oleari🇮🇹 · Marco Rocco🇮🇹

    We consider the production of a colourless system at next-to-leading order in the strong coupling constant ${\alpha }_s$. We impose a transverse-momentum cutoff, qtcut, on the colourless final state and we compute the power corrections for the inclusive cross section in the cutoff, up to the fourth power. The study of the dependence of the cross section on qtcut allows for an understanding of its behaviour at the boundaries of the phase space, giving hints on the structure at all orders in ${\alpha }_s$ and on the identification of universal patterns. The knowledge of such power corrections is also a required ingredient in order to reduce the dependence on the transverse-momentum cutoff of the QCD cross sections at higher orders, when the qt-subtraction method is applied. We present analytic results for both Drell--Yan vector boson and Higgs boson production in gluon fusion and we illustrate a process-independent procedure for the calculation of the all-order power corrections in the cutoff. In order to show the impact of the power-correction terms, we present selected numerical results and discuss how the residual dependence on qtcut affects the total cross section for Drell--Yan Z production and Higgs boson production via gluon fusion at the LHC.

    hep-phEPJC(2019)·47 citations
11. 11*

    Radiative decays in bottomonium beyond the long wave length approximation

    R. Bruschini🇪🇸 · P. González🇪🇸

    We revisit the nonrelativistic quark model description of electromagnetic radiative decays in bottomonium. We show that even for the simplest spectroscopic quark model the calculated widths can be in good agreement with data once the experimental masses of bottomonium states and the photon energy are properly implemented in the calculation. For transitions involving the lower lying spectral states this implementation can be easily done via the Long Wave Length approximation. For transitions where this approximation does not apply we develop a new method of implementing the experimental energy dependencies.

    hep-phPRD(2019)·4 citations
12. 12*

    On the different forms of the kinematical constraint in BFKL

    Michal Deak🇺🇸 · Krzysztof Kutak🇵🇱 · Wanchen Li🇺🇸 · Anna M. Staśto🇺🇸

    We perform a detailed analysis of the different forms of the kinematical constraint imposed on the low $x$ evolution that appear in the literature. We find that all of them generate the same leading anti-collinear poles in Mellin space which agree with BFKL up to NLL order and up to NNLL in $N=4$ sYM. The coefficients of subleading poles vanish up to NNLL order for all constraints and we prove that this property should be satisfied to all orders. We then demonstrate that the kinematical constraints differ at further subleading orders of poles. We quantify the differences between the different forms of the constraints by performing numerical analysis both in Mellin space and in momentum space. It can be shown that in all three cases BFKL equation can be recast into the differential form, with the argument of the longitudinal variable shifted by the combination of the transverse coordinates.

    hep-phEPJC(2019)·17 citations
13. 13*

    Constraining strongly coupled new physics from cosmic rays with machine learning techniques

    Peter Schichtel🇩🇪 · Michael Spannowsky🇬🇧 · Philip Waite🇬🇧

    Cosmic rays interacting with the atmosphere allow for the probing of fundamental interactions at ultra-high energies. We thus obtain limits on strongly coupled new physics models via their imprints on cosmic-ray air showers. Using the Monte Carlo event generators Herwig and HERBVI, and the air shower simulator CORSIKA, to simulate such processes, we apply machine learning algorithms to the simulated observables to discriminate the events arising via new physics from the QCD background. We then use the signal and background discrimination performance to set potential limits on the cross sections of the new physics models.

    hep-phastro-ph.HEEPL(2019)·5 citations
14. 14*

    QED Exponentiation for quasi-stable charged particles: the $e^{-}{e}^{+}\to W^{-}{W}^{+}$ process

    S. Jadach🇵🇱 · W. Płaczek🇵🇱 · M. Skrzypek🇵🇱

    All real and virtual infrared singularities in the standard analysis of the perturbative Quantum Electrodynamics (like that of Yennie-Frautschi-Suura) are associated with photon emissions from the external legs in the scattering process. External particles are stable, with the zero decay width. Such singularities are well understood at any perturbative order and are resummed. The case of production and decay of the semi-stable {\em neutral} particles like $Z$ boson or $\tau$ lepton, with the narrow decay width, $\Gamma /M\ll 1$, is also well understood at any perturbative order and soft photon resummation can be done. For the absent or loose upper cut-off on the total photon energy $\omega$ the production and decay process of the semi-stable (neutral) particles decouples approximately and can be considered quasi-independently. In particular soft photon resummation can be done separately for the production and decay process treating semi-stable (neutral) particle as stable. So far, consistent treatment of the soft photon resummation for semi-stable {\em charged} particles like $W^{\pm }$ boson is not available in the literature and the aim of this work is to present a solution for this problem. Generally, it should be feasible because the underlying physics is the same as in the case of the neutral semi-stable resonances -- in the limit $\Gamma /M\ll 1$ production and decay processes for charged particles also necessarily decouple due to long lifetime of the particles. The technical problems to be solved in this work are related to the fact that semi-stable charged particle are able to emit photons.

    hep-phEPJC(2020)·15 citations
15. 15*

    $l_{\alpha }\to 3l_{\beta }$ in Minimal R-symmetric Supersymmetric Standard Model

    Ke-Sheng Sun🇨🇳 · Jian-Bin Chen🇨🇳 · Hai-Bin Zhang🇨🇳 · Sheng-Kai Cui🇨🇳

    Lepton flavor violation decays are channels which may lead to fundamental discoveries in the forthcoming years and this make it an exciting research field for beyond the Standard Model searches. In this work, we present an analysis of the lepton flavor violation decays $l_{\alpha }\to 3l_{\beta }$ in Minimal R-symmetric Supersymmetric Standard Model. The prediction for BR($l_{\alpha }\to 3l_{\beta }$) depend on the off-diagonal entries of the slepton mass matrix. The contributions to Wilson coefficients can be classified into Higgs penguins, photon penguins, Z penguins, and box diagrams. It shows the contribution from Z penguins dominates the predictions for BR($l_{\alpha }\to 3l_{\beta }$), and the contributions from Higgs penguins and box diagrams play different roles in different decay channels. The theoretical predictions for BR($l_{\alpha }\to 3l_{\beta }$) can reach the future experimental limits, and there channels are very promising to be observed in near future experiment.

    hep-phMod.Phys.Lett.A(2019)·3 citations
16. 16*

    Effects of a dense medium on parameters of doubly heavy baryons

    K. Azizi🇮🇷 · N. Er🇹🇷

    The spectroscopic properties of the doubly heavy spin-$1/2$ baryons ${\Xi }_{Q{Q}^{\prime }}$, ${\Xi }_{Q{Q}^{\prime }}^{\prime }$, ${\Omega }_{Q{Q}^{\prime }}$ and ${\Omega }_{Q{Q}^{\prime }}^{\prime }$, with heavy quarks $Q$ and $Q^{\prime }$ being $b$ or/and $c$, are investigated in cold nuclear matter. In particular, the behavior of the mass of these particles with respect to the density of the medium in the range $\rho \in [0,1.4]{\rho }_{sat}$, with ${\rho }_{sat}=0.11^{3}Ge{V}^3$ being the saturation density of nuclear matter, is investigated. From the shifts in the mass and vector self energy of the states under consideration, it is obtained that ${\Xi }_{Q{Q}^{\prime }}$ and ${\Xi }_{Q{Q}^{\prime }}^{\prime }$ baryons with two heavy quarks and one $u$ or $d$ quark are affected by the medium, considerably. It is also seen that the ${\Omega }_{Q{Q}^{\prime }}$ and ${\Omega }_{Q{Q}^{\prime }}^{\prime }$ states, containing two heavy quarks and one $s$ quark do not see the dense medium, at all. The value of mass for the ${\Xi }_{cc}$ state obtained at $\rho \to 0$ limit is nicely consistent with the experimental data. Our results on parameters of other members can be useful in the search for these states. The obtained results may also shed light on the future in-medium experiments aiming to search for the behavior of the doubly heavy baryons under extreme conditions.

    hep-phhep-exnucl-thPRD(2019)·8 citations
17. 17*

    Exploring the global symmetry structure of the Higgs potential via same-sign pair production of charged Higgs bosons

    Masashi Aiko🇯🇵 · Shinya Kanemura🇯🇵 · Kentarou Mawatari🇯🇵

    We propose a novel process where singly charged Higgs bosons are produced in a same-sign pair via vector boson fusion at hadron colliders in two Higgs doublet models. The process directly relates to the global symmetry structure of the Higgs potential. The produced charged Higgs bosons predominantly decay into a tau lepton and the neutrino or into a pair of top and bottom quarks, depending on the type of Yukawa interactions. We evaluate the signal and the background for the both cases at the CERN Large Hadron Collider and future higher-energy hadron colliders. We find that the process can be feasible and useful to explore the nature of the Higgs potential.

    hep-phhep-exPLB(2019)·17 citations
18. 18*

    QCD and High Energy Interactions: MORIOND 2019 Theory Summary

    D. Wackeroth🇺🇸

    Highlights of recent theory developments are summarized relevant to precision Standard Model (SM) studies and searches for Beyond-the-SM (BSM) phenomena at present and future high-energy pp and e+ e- colliders, and B-factories, as well as to selected topics in heavy ion collisions.

    hep-ph4 citations
19. 19*

    New partial symmetries from group algebras for lepton mixing

    Shu-Jun Rong🇨🇳

    Recent stringent experiment data of neutrino oscillations induces partial symmetries such as $Z_2$, $Z_2\times CP$ to derive lepton mixing patterns. New partial symmetries expressed with elements of group algebras are studied. A specific lepton mixing pattern could correspond to a set of equivalent elements of a group algebra. The transformation which interchanges the elements could express a residual $CP$ symmetry. Lepton mixing matrices from $S_3$ group algebras are of the trimaximal form with the $\mu -\tau$ reflection symmetry. Accordingly, elements of $S_3$ group algebras are equivalent to $Z_2\times CP$. Comments on $S_4$ group algebras are given. The predictions of $Z_2\times CP$ broken from the group $S_4$ with the generalized $CP$ symmetry are also obtained from elements of $S_4$ group algebras.

    hep-phAdv.High Energy Phys.(2020)·2 citations
20. 20*

    Addendum to: A Theoretical Study of Top-Mass Measurements at the LHC Using NLO+PS Generators of Increasing Accuracy

    Silvia Ferrario Ravasio🇮🇹 · Tomas Jezo🇨🇭 · Paolo Nason🇮🇹 · Carlo Oleari🇮🇹

    This paper is a follow-up of Ref.~\cite{Ravasio:2018lzi}, where we studied the impact of next-to-leading order calculations merged with parton shower generators (NLO+PS) of increasing accuracy in the extraction of the top mass at hadron colliders. Here we examined results obtained with the older (fortran-based) shower generators Pythia6.4 and Herwig6.5. Our findings are in line with what we found in our previous paper with the new, c++-based, generators Pythia8.2 and Herwig7.1.

    hep-phEPJC(2018)·79 citations
21. 21*

    Lepton non-universality in $B$-decays in the minimal leptoquark gauge model

    Michal Malinský🇨🇿

    The anomalies in semileptonic $B$-decays are often attributed to new physics scenarios featuring leptoquark degrees of freedom. Attempts to accommodate all the deviations at once usually result in an elaborate model building way beyond the minimal scenarios containing the desired degrees of freedom. However, as it is far from clear whether all these signals (if any) survives the future experimental scrutiny, in this contribution we decided to take the opposite standpoint and review the actual room available for various $B$-decay anomalies within the very minimal low-energy leptoquark gauge model based on the $SU(4{)}_C\otimes SU(2{)}_L\otimes U(1{)}_R$ symmetry group.

    hep-ph1 citation
22. 22*

    Accommodating three low-scale anomalies (g-2, Lamb shift, and Atomki) in the framed standard model

    José BORDES (1)🇪🇸 · CHAN Hong-Mo (2)🇬🇧 · TSOU Sheung Tsun (3) ((1) Departament Fisica Teorica and IFIC, CSIC-Universitat de Valencia, Spain, (2) Rutherford Appleton Laboratory, United Kingdom, (3) Mathematical Institute, University of Oxford, United Kingdom)🇬🇧

    The framed standard model (FSM) predicts a $0^{+}$ boson with mass around 20 MeV in the "hidden sector", which mixes at tree level with the standard Higgs $h_W$ and hence acquires small couplings to quarks and leptons which can be calculated in the FSM apart from the mixing parameter ${\rho }_{Uh}$. The exchange of this mixed state $U$ will contribute to $g-2$ and to the Lamb shift. By adjusting ${\rho }_{Uh}$ alone, it is found that the FSM can satisfy all present experimental bounds on the $g-2$ and Lamb shift anomalies for $\mu$ and $e$, and for the latter for both hydrogen and deuterium. The FSM predicts also a $1^{-}$ boson in the "hidden sector" with a mass of 17 MeV, that is, right on top of the Atomki anomaly $X$. This mixes with the photon at 1-loop level and couples thereby like a dark photon to quarks and leptons. It is however a compound state and is thought likely to possess additional compound couplings to hadrons. By adjusting the mixing parameter and the $X$'s compound coupling to nucleons, the FSM can reproduce the production rate of the $X$ in beryllium decay as well as satisfy all the bounds on $X$ listed so far in the literature. The above two results are consistent in that the $U$, being $0^{+}$, does not contribute to the Atomki anomaly if parity and angular momentum are conserved, while $X$, though contributing to $g-2$ and Lamb shift, has smaller couplings than $U$ and can, at first instance, be neglected there. Despite the tentative nature of the 3 anomalies in experiment and of the FSM as theory, the accommodation of the former in the latter has strengthened the credibility of both. If this FSM interpretation were correct, it would change the whole aspect of the anomalies from just curiosities to windows into a vast hitherto hidden sector comprising at least in part the dark matter which makes up the bulk of our universe.

    hep-phInt.J.Mod.Phys.A(2019)·23 citations
23. 23*

    Test of Lorentz Violation with Astrophysical Neutrino Flavor in IceCube

    Teppei Katori🇬🇧 · Carlos A. Argüelles🇺🇸 · Kareem Farrag🇬🇧 · Shivesh Mandalia🇬🇧

    Astrophysical high-energy neutrinos observed by IceCube are sensitive to small effects in a vacuum such as those motivated from quantum gravity theories. Here, we discuss the potential sensitivity of Lorentz violation from the diffuse astrophysical neutrino data in IceCube. The estimated sensitivity reaches the Planck scale physics motivated region, providing IceCube with real discovery potential of Lorentz violation.

    hep-ph8 citations
24. 24*

    Quantum chromodynamics axion in a hot and magnetized medium

    Aritra Bandyopadhyay🇧🇷 · Ricardo L. S. Farias🇧🇷 · Bruno S. Lopes🇧🇷 · Rudnei O. Ramos🇧🇷

    It is analyzed the effects of a hot and magnetized medium on the axion mass, self-coupling and topological susceptibility when in presence of an anisotropic external magnetic field along the $z$-direction, within the Nambu--Jona-Lasinio effective model for quantum chromodynamics. The effects of both Magnetic Catalysis and Inverse Magnetic Catalysis are explicitly taken into account through appropriate matching of parameters with those from lattice Monte-Carlo numerical simulations. It is also analyzed the dependence of the results with respect to different model parametrizations in the context of the Nambu--Jona-Lasinio model.

    hep-phhep-thnucl-thPRD(2019)·33 citations
25. 25*

    Thermal Relic Targets with Exponentially Small Couplings

    Raffaele Tito D'Agnolo🇺🇸 · Duccio Pappadopulo🇺🇸 · Joshua T. Ruderman🇺🇸 · Po-Jen Wang🇺🇸

    If dark matter was produced in the early Universe by the decoupling of its annihilations into known particles, there is a sharp experimental target for the size of its coupling. We show that if dark matter was produced by inelastic scattering against a lighter particle from the thermal bath, then its coupling can be exponentially smaller than the coupling required for its production from annihilations. As an application, we demonstrate that dark matter produced by inelastic scattering against electrons provides new thermal relic targets for direct detection and fixed target experiments.

    hep-phastro-ph.COhep-exPRL(2020)·38 citations
26. 26*

    Searching for muonic forces with the ATLAS detector

    Iftah Galon🇺🇸 · Enrique Kajamovitz🇮🇱 · David Shih🇺🇸 · Yotam Soreq🇮🇱 · Shlomit Tarem🇮🇱

    The LHC copiously produces muons via different processes, and the muon sample will be large at the high-luminosity LHC (HL-LHC). In this work we propose to leverage this large muon sample and utilize the HL-LHC as a muon fixed-target experiment, with the ATLAS calorimeter as the target. We consider a novel analysis for the ATLAS detector, which takes advantage of the two independent muon momentum measurements by the inner detector and the muon system. We show that a comparison of the two measurements, before and after the calorimeters, can probe new force carriers that are coupled to muons and escape detection. The proposed analysis, based on muon samples from $W$ and $Z$ decays only, has a comparable reach to other proposals. In particular, it can explore the part of parameter-space that could explain the muon $g-2$ anomaly.

    hep-phhep-exPRD(2020)·36 citations
27. 27*

    Aspects of heavy flavor jet physics in heavy ion collisions

    Ivan Vitev🇺🇸

    n these proceedings I discuss several recent developments in the physics of heavy flavor jets in heavy ion collisions. i) The dijet mass modification in nucleus-nucleus reactions has been proposed as a new observable with enhanced sensitivity to parton energy loss in nuclear matter. It also enables more precise studies of heavy quark mass effects on parton shower formation. ii) Computational techniques from soft-collinear effective theory have allowed us to bridge the gap between high energy and heavy ion QCD phenomenology. I show the first application of the semi-inclusive jet function formalism to heavy flavor jet production in proton-nucleus and nucleus-nucleus collisions at the LHC. iii) Last but not least, central to the theoretical calculations of heavy flavor jets is the accurate theoretical description of in-medium parton showers. A formalism to compute branching processes in nuclear matter to any desired order in opacity has been developed and illustrative numerical results are presented.

    hep-phnucl-thPoS(2020)·1 citation
28. 28*

    Discrete remnants of orbifolding

    Steffen Biermann🇬🇧 · Andreas Mütter🇩🇪 · Erik Parr🇩🇪 · Michael Ratz🇺🇸 · Patrick K.S. Vaudrevange🇩🇪

    We revisit the residual symmetries that survive the orbifold projections, and find additional transformations that have been overlooked in the past. Some of these transformations are outer automorphisms of the downstairs continuous symmetry group. Examples for these transformations include the left-right parity of the Pati-Salam model and its left-right symmetric subgroup.

    hep-phhep-thPRD(2019)·11 citations
29. 29*

    Experimental study for leptonic and semileptonic decays in the charm sector

    S. F. Zhang (On behalf of the BESIII Collaboration)🇨🇳

    Leptonic and semileptonic decays in the charm sector have been well studied in recent years. With the largest data sample near $D\bar{D}$ threshold, precision measurements of leptonic and semileptonic decays of charm meson and baryon are perfromed at BESIII. Test for letpon flavor universality is also performed. Sensitivity for rare leptonic and semileptonic charm decays is significantly improved taking advantage of the huge statistics in LHCb and the $B$ factories.

    ↳ hep-exhep-ph1 citation
30. 30*

    Measuring Momentum-Dependent Flow Fluctuations in Heavy-Ion Collisions

    Mauricio Hippert🇧🇷 · David Dobrigkeit Chinellato🇧🇷 · Matthew Luzum🇧🇷 · Jorge Noronha🇧🇷 · Tiago Nunes da Silva🇧🇷 · Jun Takahashi🇧🇷

    In heavy-ion collisions, momentum-dependent pair correlations can be characterized by a principal component analysis (PCA), in which subleading modes are expected to reveal new information on flow fluctuations. However, we find that, as currently measured, these modes can be dominated by multiplicity fluctuations, which serve as an unwanted background. Here, we propose new PCA observables that are robust against multiplicity fluctuations and isolate novel sources of flow fluctuations, thus being suited to provide fresh insight into the initial stages of the system at small length scales.

    ↳ nucl-thhep-phnucl-exPRC(2020)·15 citations
31. 31*

    BESIII Exotics

    G. Mezzadri (on behalf of the BESIII collaboration)🇮🇹

    Since few years, a new family of exotic states has been appearing above the open-heavy meson thresholds: the so-called $XYZ$ states. BESIII at the BEPCII $e^{+}{e}^{-}$ collider plays a unique role in the study of those particles in the charmonium sector. Changing the beam energy, BESIII can collect large data samples by means of scans of the resonant region, accessing directly to all vector states. As part of a larger upgrade program, BESIII has planned to increase the center of mass energy to reach $4.7$ GeV: this will allow BESIII to investigate the nature of the $Y(4660)$, that was at first observed by Belle and BaBar after Initial State Radiation only in $\pi \pi \psi (2s)$ and ${\Lambda }_c$ ${\bar{\Lambda }}_c$ final states. The relative branching ratio seems to point toward a baryonium interpretation of the resonance, as expected in Rossi-Veneziano model. BESIII can directly measure the cross sections around the expected peak position and verify this prediction. In this presentation, the status of the $XYZ$ searches at BESIII will be presented, with a focus also on the plans for the newest data taking and for the $Y(4660)$ studies.

    ↳ hep-exhep-ph0 citations
32. 32*

    Neutron stars in $f(R)$ gravity and scalar-tensor theories

    Ryotaro Kase🇯🇵 · Shinji Tsujikawa🇯🇵

    In $f(R)$ gravity and Brans-Dicke theory with scalar potentials, we study the structure of neutron stars on a spherically symmetric and static background for two equations of state: SLy and FPS. In massless BD theory, the presence of a scalar coupling $Q$ with matter works to change the star radius in comparison to General Relativity, while the maximum allowed mass of neutron stars is hardly modified for both SLy and FPS equations of state. In Brans-Dicke theory with the massive potential $V(\varphi )=m^2{\varphi }^2/2$, where $m^2$ is a positive constant, we show the difficulty of realizing neutron star solutions with a stable field profile due to the existence of an exponentially growing mode outside the star. As in $f(R)$ gravity with the $R^2$ term, this property is related to the requirement of extra boundary conditions of the field at the surface of star. For the self-coupling potential $V(\varphi )=\lambda {\varphi }^4/4$, this problem can be circumvented by the fact that the second derivative $V_{,\varphi \varphi }=3\lambda {\varphi }^2$ approaches 0 at spatial infinity. In this case, we numerically show the existence of neutron star solutions for both SLy and FPS equations of state and discuss how the mass-radius relation is modified as compared to General Relativity.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2019)·44 citations
33. 33*

    Anomalous Casimir effect in axion electrodynamics

    Kenji Fukushima🇯🇵 · Shota Imaki🇯🇵 · Zebin Qiu🇯🇵

    We study the Casimir effect in axion electrodynamics. A finite $\theta$-term affects the energy dispersion relation of photon if $\theta$ is time and/or space dependent. We focus on a special case with linearly inhomogeneous $\theta$ along the $z$-axis. Then we demonstrate that the Casimir force between two parallel plates perpendicular to the $z$-axis can be either attractive or repulsive, dependent on the gradient of $\theta$. We call this repulsive component in the Casimir force induced by inhomogeneous $\theta$ the anomalous Casimir effect.

    ↳ hep-thcond-mat.mes-hallhep-phquant-phPRD(2019)·35 citations
34. 34*

    Primordial Black Holes from Broad Spectra: Abundance and Clustering

    A. Moradinezhad Dizgah🇺🇸 · G. Franciolini🇨🇭 · A. Riotto🇨🇭

    A common mechanism to form primordial black holes in the early universe is by enhancing at small-scales the scalar perturbations generated during inflation. If these fluctuations have a large enough amplitude, they may collapse into primordial black holes upon horizon re-entry. Such primordial black holes may comprise the totality of the dark matter. We offer some considerations about the formation and clustering of primordial black holes when the scalar perturbations are characterised by a broad spectrum. Using the excursion set method, as well as the supreme statistics, we show that the cloud-in-cloud phenomenon, for which small mass primordial black holes may be absorbed by bigger mass ones, is basically absent. This is due to the fact that the formation of a primordial black hole is an extremely rare event. We also show that, from the point of view of mass distribution, broad and narrow spectra give similar results in the sense that the mass distribution is tilted towards a single mass. Furthermore, we argue that primordial black holes from broad spectra are not clustered at formation, their distribution is dominantly Poissonian.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·94 citations
35. 35*

    Time Reversal Violation in Light Nuclei

    A. Gnech🇮🇹 · M. Viviani🇮🇹

    Time Reversal Violation (TRV) interactions between quarks which appear in Standard Model (SM) and beyond-SM theories can induce TRV components in the nucleon-nucleon potential. The effects of these components can be studied by measuring the electric dipole moment (EDM) of light nuclei. In this work we present a complete derivation of the TRV nucleon-nucleon and three-nucleon potential up to next-to-next-to leading order (N2LO) in a chiral effective field theory (chiEFT) framework. The TRV interaction is then used to evaluate the EDM of 2H, 3H and 3he focusing in particular on the effects of the TRV three-body force and on the calculation of the theoretical errors. In case of a measurement of the EDM of these nuclei, the result of present work would permit to determine the values of the low energy constants and to identify the source of TRV.

    ↳ nucl-thhep-phPRC(2020)·20 citations
36. 36*

    Constraints on decaying dark matter from weak lensing and cluster counts

    Kari Enqvist🇫🇮 · Seshadri Nadathur🇬🇧 · Toyokazu Sekiguchi🇯🇵 · Tomo Takahashi🇯🇵

    We revisit a cosmological constraint on dark matter decaying into dark radiation at late times. In Enqvist et al. (2015), we mainly focused on the effects of decaying dark matter (DDM) on the cosmic microwave background (CMB) and nonlinear matter power spectrum. Extending our previous analysis, here we use N-body simulation to investigate how DDM affects the halo mass function. This allows us to incorporate the cluster counts observed by the Sunyaev-Zel'dovich effect to study a bound on the lifetime of DDM. We also update the data of CMB and cosmic shear power spectrum with the Planck 2015 results and KiDS450 observations, respectively. From these cosmological observations, we obtain an lower bound on the lifetime ${\Gamma }^{-1}\ge 175$Gyr from the Planck2015 results (CMB+SZ cluster count) combined with the KiDS450 and the recent measurements of the baryon acoustic scale.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·35 citations
37. 37*

    Fingerprint matching of beyond-WIMP dark matter: neural network approach

    Kyu Jung Bae🇰🇷 · Ryusuke Jinno🇩🇪 · Ayuki Kamada🇰🇷 · Keisuke Yanagi🇯🇵

    Galactic-scale structure is of particular interest since it provides important clues to dark matter properties and its observation is improving. Weakly interacting massive particles (WIMPs) behave as cold dark matter on galactic scales, while beyond-WIMP candidates suppress galactic-scale structure formation. Suppression in the linear matter power spectrum has been conventionally characterized by a single parameter, the thermal warm dark matter mass. On the other hand, the shape of suppression depends on the underlying mechanism. It is necessary to introduce multiple parameters to cover a wide range of beyond-WIMP models. Once multiple parameters are introduced, it becomes harder to share results from one side to the other. In this work, we propose adopting neural network technique to facilitate the communication between the two sides. To demonstrate how to work out in a concrete manner, we consider a simplified model of light feebly interacting massive particles.

    ↳ astro-ph.COhep-phJCAP(2020)·6 citations
38. 38*

    Quantum radiation reaction in aligned crystals beyond the local constant field approximation

    T. N. Wistisen🇩🇪 · A. Di Piazza🇩🇪 · C. F. Nielsen🇩🇰 · A. H. Sørensen🇩🇰 · U. I. Uggerhøj🇩🇰

    We report on experimental spectra of photons radiated by 50 GeV positrons crossing silicon single crystals of thicknesses 1.1 mm, 2.0 mm, 4.2 mm, and 6.2 mm at sufficiently small angles to the (110) planes that their motion effectively is governed by the continuum crystal potential. The experiment covers a new regime of interaction where each positron emits several hard photons, whose recoil are not negligible and which are formed on lengths where the variation of the crystal field cannot be ignored. As a result neither the single-photon semiclassical theory of Baier et al. nor the conventional cascade approach to multiple hard photon emissions (quantum radiation reaction) based on the local constant field approximation are able to reproduce the experimental results. After developing a theoretical scheme which incorporates the essential physical features of the experiments, i.e., multiple emissions, photon recoil and background field variation within the radiation formation length, we show that it provides results in convincing agreement with the data.

    ↳ physics.plasm-phhep-exhep-phPhys.Rev.Research.(2019)·24 citations
39. 39*

    Pentaquarks

    Lorenzo Capriotti (on behalf of the LHCb collaboration)🇮🇹

    The field of exotic spectroscopy is extremely rich and productive. Several observations and searches for pentaquark states have been performed in the last 4 years, starting from the LHCb observation in 2015. This is still quite a recent discovery, and possibly the beginning of a new era in both observation of new states and understanding of the QCD binding mechanisms. The most recent results from LHCb and Belle are presented regarding measurements and searches for charm, strange and beauty pentaquarks, along with an introduction on phenomenology of multiquark states.

    ↳ hep-exhep-ph0 citations
40. 40*

    Reconstructing the spectral shape of a stochastic gravitational wave background with LISA

    Chiara Caprini🇫🇷 · Daniel G. Figueroa🇨🇭 · Raphael Flauger🇺🇸 · Germano Nardini🇳🇴 · Marco Peloso🇮🇹 · Mauro Pieroni🇪🇸 · Angelo Ricciardone🇮🇹 · Gianmassimo Tasinato🇬🇧

    We present a set of tools to assess the capabilities of LISA to detect and reconstruct the spectral shape and amplitude of a stochastic gravitational wave background (SGWB). We first provide the LISA power-law sensitivity curve and binned power-law sensitivity curves, based on the latest updates on the LISA design. These curves are useful to make a qualitative assessment of the detection and reconstruction prospects of a SGWB. For a quantitative reconstruction of a SGWB with arbitrary power spectrum shape, we propose a novel data analysis technique: by means of an automatized adaptive procedure, we conveniently split the LISA sensitivity band into frequency bins, and fit the data inside each bin with a power law signal plus a model of the instrumental noise. We apply the procedure to SGWB signals with a variety of representative frequency profiles, and prove that LISA can reconstruct their spectral shape. Our procedure, implemented in the code SGWBinner, is suitable for homogeneous and isotropic SGWBs detectable at LISA, and it is also expected to work for other gravitational wave observatories.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2019)·303 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.