Tue·Mar 19, 2019Tuesday·March 19, 2019

1. 01*

   Pion induced Drell-Yan: the transverse momentum structure of the pion

   A. Courtoy🇲🇽

   We present an analysis of unpolarized Drell-Yan pair production in pion-nucleus scattering with a particular focus into the pion dynamics. The study consists in analyzing the effect of the partonic longitudinal and, especially, transverse distributions of the pion in a Nambu--Jona-Lasinio (NJL) framework, with Pauli-Villars regularization. In order to consistently take into account the QCD evolution effects, we have estimated the hadronic scale corresponding to the NJL model's degrees of freedom through a minimization procedure at NLO: The NLO evolved pion distributions have been compared to rapidity differential Drell-Yan cross sections data. That hadronic scale so determined represents the only free parameter in our approach. The NJL transverse momentum PDF, evolved up to next-to-leading logarithmic accuracy, is then tested against the transverse momentum spectrum of dilepton pairs up to a transverse momentum of 2 GeV. We found a fair agreement with available pion-nucleus data. We find sizable evolution effects on the shape of the distributions and on the generated average transverse momentum of the dilepton pair.

   hep-phJ.Phys.Conf.Ser.(2019)·0 citations
2. 02*

   Shape of the quark gluon plasma droplet reflected in the high-p_T data

   Magdalena Djordjevic🇷🇸 · Stefan Stojku🇷🇸 · Marko Djordjevic🇷🇸 · Pasi Huovinen🇷🇸

   We show, through analytic arguments, numerical calculations, and comparison with experimental data, that the ratio of the high-p_T observables v_2/(1-R_AA) reaches a well-defined saturation value at high p_T, and that this ratio depends only on the spatial anisotropy of the quark gluon plasma (QGP) formed in ultrarelativistic heavy-ion collisions. With expected future reduction of experimental errors, the anisotropy extracted from experimental data will further constrain the calculations of initial particle production in heavy-ion collisions and thus test our understanding of QGP physics.

   hep-phnucl-thPRC(2019)·6 citations
3. 03*

   Multiplicity moments of shifted Gompertz distribution in $e^{+}{e}^{-}$, $p\bar{p}$ and $pp$ collisions at high energies

   Aayushi Singla🇮🇳 · M. Kaur🇮🇳

   In continuation of our earlier work, in which we analysed the charged particle multiplicities in leptonic and hadronic interactions at different center of mass energies in full phase space as well as in restricted phase space with the shifted Gompertz distribution, a detailed analysis of the normalized and factorial moments is reported here. A two-component model in which probability distribution function is obtained from the superposition of two shifted Gompertz distributions introduced in our earlier work has also been used for the analysis. This is the first analysis of the moments with the shifted Gompertz distribution. Analysis has also been done to predict the moments of multiplicity distribution for the electron-positron collisions at c.m. energy of 500 GeV at a future Collider.

   hep-ph0 citations
4. 04*

   $X(3872)$ as virtual companion pole of the charm-anticharm state ${\chi }_{c1}(2P)$

   Francesco Giacosa🇵🇱 · Milena Piotrowska🇵🇱 · Susana Coito🇵🇱

   We study the spectral function of the axial-vector charmonium state ${\chi }_{c1}(2P)$ coupled to $D{D}^{\ast }$ mesons, by employing a quantum field theoretical approach: a pronounced enhancement close to the $D^0$ threshold, to be identified with the $X(3872)$, emerges. In the complex plane we find two poles: a pole for the broad seed state ${\chi }_{c1}(2P)$, and -- in the easiest scenario -- a virtual pole for the $X(3872)$. Thus, our approach describes both the seed state and the dynamically generated $X(3872)$ simultaneously. In particular, it explains the most prominent, both molecular-like and quarkonium-like, features of the $X(3872)$: its very small width (the decay into $D^0{D}^{\ast 0}$ is predicted to be about 0.5 MeV), the enhanced radiative decay into $\psi (2S)\gamma$ w.r.t. $\psi (1S)\gamma$, and the isospin breaking decay into $J/\psi \rho$ (thanks to $D{D}^{\ast }$ loops mediating this decay channel). At the same time, we aim to determine the pole position and the properties of the charmonium seed state: quite interestingly, even if a pole is always present, it is possible that there is no peak corresponding to this state in the spectral function, thus potentially explaining why the corresponding resonance could not yet be seen in experiments.

   hep-phInt.J.Mod.Phys.A(2019)·24 citations
5. 05*

   $B_{s(d)}-{\bar{B}}_{s(d)}$ Mixing and $B_s\to {\mu }^{+}{\mu }^{-}$ Decay in the NMSSM with the Flavour Expansion Theorem

   Quan-Yi Hu🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳 · Min-Di Zheng🇨🇳

   In this paper, motivated by the observation that the Standard Model predictions are now above the experimental data for the mass difference $\Delta M_{s(d)}$, we perform a detailed study of $B_{s(d)}-{\bar{B}}_{s(d)}$ mixing and $B_s\to {\mu }^{+}{\mu }^{-}$ decay in the ${\mathbb{Z}}_3$-invariant NMSSM with non-minimal flavour violation, using the recently developed procedure based on the Flavour Expansion Theorem, with which one can perform a purely algebraic mass-insertion expansion of an amplitude written in the mass eigenstate basis without performing any diagrammatic calculations in the interaction/flavour basis. Specifically, we consider the finite orders of mass insertions for neutralinos but the general orders for squarks and charginos, under two sets of assumptions for the squark flavour structures (\textit{i.e.}, while the flavour-conserving off-diagonal element ${\delta }_{33}^{\text{LR}}$ is kept in both of these two sectors, only the flavour-violating off-diagonal elements ${\delta }_{23}^{\text{LL}}$ and ${\delta }_{i3}^{\text{RR}}$ ($i=1,2$) are kept in the \text{LL} and \text{RR} sectors, respectively). Our analytic results are then expressed directly in terms of the initial Lagrangian parameters in the interaction/flavour basis, making it easy to impose the experimental bounds on them. It is found numerically that the NMSSM effects with the above two assumptions for the squark flavour structures can accommodate the observed deviation for $\Delta M_{s(d)}$, while complying with the experimental constraints from the branching ratios of $B_s\to {\mu }^{+}{\mu }^{-}$ and $B\to X_s\gamma$ decays.

   hep-phJHEP(2019)·6 citations
6. 06*

   On Shell Renormalization Scheme From the Loopwise Expansion of the Pole Mass

   Chungku Kim🇰🇷

   We introduce an on shell renormalization scheme in which the mass parameter of minimal MS scheme is replaced with the pole mass obtained from the loop order expansion of the pole mass in the MS scheme. As a consequence, the quartic coupling constant remains same as that of the MS scheme and the vacuum expectation value gets contributions from the one-particle-irreducible diagrams. We also show the renormalization group invariance of the pole mass in this scheme.

   hep-phNew Phys.Sae Mulli(2019)·0 citations
7. 07*

   Constructing $J/\psi$ family with updated data of charmoniumlike $Y$ states

   Jun-Zhang Wang🇨🇳 · Dian-Yong Chen🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

   Based on the updated data of charmoniumlike state $Y(4220)$ reported in the hidden-charm %and open-charm channels of the $e^{+}{e}^{-}$ annihilation, we propose a $4S$-$3D$ mixing scheme to categorize $Y(4220)$ into the $J/\psi$ family. We find that the present experimental data can support this charmonium assignment to $Y(4220)$. Thus, $Y(4220)$ plays a role of a scaling point in constructing higher charmonia above 4 GeV. To further test this scenario, we provide more abundant information on the decay properties of $Y(4220)$, and predict its charmonium partner $\psi (4380)$, whose evidence is found by analyzing the $e^{+}{e}^{-}\to \psi (3686){\pi }^{+}{\pi }^{-}$ data from BESIII. If $Y(4220)$ is indeed a charmonium, we must face how to settle the established charmonium $\psi (4415)$ in the $J/\psi$ family. In this work, we may introduce a $5S$-$4D$ mixing scheme, and obtain the information of the resonance parameters and partial open-charm decay widths of $\psi (4415)$, which do not contradict the present experimental data. Additionally, we predict a charmonium partner $\psi (4500)$ of $\psi (4415)$, which can be accessible at future experiments, especially, BESIII and BelleII. The studies presented in this work provide new insights to establish the higher charmonium spectrum.

   hep-phhep-exhep-latPRD(2019)·92 citations
8. 08*

   The perturbative QCD predictions for the decay B^{0}_{s}\rightarrow SS(a_{0}(980),f_{0}(980),f_{0}(500))

   Ze-Rui Liang🇨🇳 · Xian-Qiao Yu🇨🇳

   In this work, we calculate the branching ratios and CP violations of the B^{0}_{s}\rightarrow a_{0}(980)a_{0}(980) decay modes with both charged and neutral a_{0}(980) mesons and B^{0}_{s}\rightarrow f_{0}(980)(f_{0}(500))f_{0}(980)(f_{0}(500)) for the first time in the pQCD approach. Considering the recent observation of the BESIII collaboration that provide a direct information about the constituent two-quark components in the corresponding a_{0}(980) wave functions, we regard the scalar mesons a_{0}(980), f_{0}(980) and f_{0}(500) as the q\bar{q} quark component in our present work, and then make predictions of these decay modes. The branching ratios of our calculations are at the order of the 10^{-4}\sim10^{-6} when we consider the mixing scheme. We also calculate the CP violation parameters of these decay modes. The relatively large branching ratios make it easily to be tested by the running LHC-b experiments, and it can help us to understand both the inner properties and the QCD behavior of the scalar meson.

   hep-phPRD(2020)·12 citations
9. 09*

   Analytic Next-To-Leading Order Calculation of Energy-Energy Correlation in Gluon-Initiated Higgs Decays

   Ming-xing Luo🇨🇳 · Vladyslav Shtabovenko🇨🇳 · Tong-Zhi Yang🇨🇳 · Hua Xing Zhu🇨🇳

   The energy-energy correlation (EEC) function in $e^{+}{e}^{-}$ annihilation is currently the only QCD event shape observable for which we know the full analytic result at the next-to-leading order (NLO). In this work we calculate the EEC observable for gluon initiated Higgs decay analytically at NLO in the Higgs Effective Field Theory (HEFT) framework and provide the full results expressed in terms of classical polylogarithms, including the asymptotic behavior in the collinear and back-to-back limits. This observable can be, in principle, measured at the future $e^{+}{e}^{-}$ colliders such as CEPC, ILC, FCC-ee or CLIC. It provides an interesting opportunity to simultaneously probe our understanding of the strong and Higgs sectors and can be used for the determinations of the strong coupling.

   hep-phJHEP(2019)·87 citations
10. 10*

    More about Q-ball with elliptical orbit

    Fuminori Hasegawa🇯🇵 · Jeong-Pyong Hong🇰🇷 · Motoo Suzuki🇯🇵

    Q-balls formed from the Affleck-Dine field have rich cosmological implications and have been extensively studied from both theoretical and simulational approaches. From the theoretical point of view, the exact solution of the Q-ball was obtained and it shows a circular orbit in the complex plane of the field value. In practice, however, it is reported that the Q-ball that appears after the Affleck-Dine mechanism has an $elliptical$ orbit, which carries larger energy per unit $U(1)$ charge than the well-known solution with a circular orbit. We call them "elliptical" Q-balls. In this paper, we report the first detailed investigation of the properties of the elliptical Q-balls by $3$D lattice simulation. The simulation results indicate that the elliptical Q-ball has an almost spherical spatial profile with no nodes, and we observed a highly elliptic orbit that cannot be described through small perturbations around the ground state Q-ball. Higher ellipticity leads to more excitation of the energy, whose relation is also derived as a dispersion relation. Finally, we derive two types of approximate solutions by extending the Gaussian approximation and considering the time-averaged equation of motion and we also show the consistency with the simulation results.

    hep-phastro-ph.COPLB(2019)·4 citations
11. 11*

    A Grand Unified Parity Solution to Strong CP Problem

    Yukihiro Mimura🇯🇵 · Rabindra N. Mohapatra🇺🇸 · Matt Severson🇺🇸

    A beyond the standard model theory that respects parity symmetry at short distances is known to provide a solution to the strong CP problem without the need for an axion, while keeping the CKM phase unconstrained. In this paper we present a supersymmetric SO(10) grand unified embedding of this idea with Yukawa couplings generated by {\bf 10}, $\overline{126}$ and {\bf 120} Higgs fields. This model is known to provide a unified description of masses and mixings of quarks and leptons. When CP symmetry is imposed on this model, the discrete gauge subgroup C of SO(10) combines with it to generate an effective parity symmetry, leading to hermitian quark mass matrices. Imposing an additional discrete symmetry, $G$, we show that there are no other tree level sources of $\theta$ in the model; $G$ also guarantees that the one- and two-loop contributions to $\theta$ vanish. We then show that the leading three-loop effects and the effect of higher-dimensional operators invariant under $G$ give rise to $\theta$ near the current experimental bound, making the model testable in the current searches for neutron electric dipole moment.

    hep-phPRD(2019)·21 citations
12. 12*

    Dark Neutrinos and a Three Portal Connection to the Standard Model

    Peter Ballett🇬🇧 · Matheus Hostert🇬🇧 · Silvia Pascoli🇬🇧

    We introduce a dark neutrino sector which respects a hidden $U(1{)}^{\prime }$ gauge symmetry, subsequently broken by the vacuum expectation value of a dark scalar. The model is a self-consistent realisation of an extended hidden sector that communicates with the SM only via the three renormalizable portals, namely neutrino, vector and scalar mixing. The interplay between portal couplings leads to several novel signatures in heavy neutrino, dark photon, and dark scalar searches, typically characterised by multi-leptons plus missing energy and displaced vertices. A striking signature arises in kaon factories such as NA62, where $K^{+}\to {\ell }_{\alpha }^{+}\nu {\ell }_{\beta }^{+}{\ell }_{\beta }^{-}$ decays could reveal a heavy neutrino and a light dark photon resonance above backgrounds. Given the open parameter space, we also comment on recent ideas to explain outstanding experimental anomalies, and how they would fit in our proposed model. A minimal extension of the model, possibly motivated by anomaly cancellation, can accommodate a dark matter candidate strongly connected to the neutrino sector.

    hep-phPRD(2020)·111 citations
13. 13*

    Neutrino Masses from a Dark Neutrino Sector below the Electroweak Scale

    Peter Ballett🇬🇧 · Matheus Hostert🇬🇧 · Silvia Pascoli🇬🇧

    We consider a minimal extension of the Standard Model which advocates a dark neutrino sector charged under a hidden $U(1{)}^{\prime }$. We show that neutrino masses can arise radiatively in this model. The observed values are compatible with a light dark sector below the electroweak scale and would imply new heavy fermions which may be testable in the next generation of beam dump searches at DUNE, NA62 and SHIP.

    hep-phPRD(2019)·60 citations
14. 14*

    Lepton Flavor Violation and Collider Searches in a Type I + II Seesaw Model

    Manoel M. Ferreira🇧🇷 · Tessio B. de Melo🇧🇷 · Sergey Kovalenko🇨🇱 · Paulo R. D. Pinheiro🇧🇷 · Farinaldo S. Queiroz🇧🇷

    Neutrino are massless in the Standard Model. The most popular mechanism to generate neutrino masses are the type I and type II seesaw, where right-handed neutrinos and a scalar triplet are augmented to the Standard Model, respectively. In this work, we discuss a model where a type I + II seesaw mechanism naturally arises via spontaneous symmetry breaking of an enlarged gauge group. Lepton flavor violation is a common feature in such setup and for this reason, we compute the model contribution to the $\mu \to e\gamma$ and $\mu \to 3e$ decays. Moreover, we explore the connection between the neutrino mass ordering and lepton flavor violation in perspective with the LHC, HL-LHC and HE-LHC sensitivities to the doubly charged scalar stemming from the Higgs triplet. Our results explicitly show the importance of searching for signs of lepton flavor violation in collider and muon decays. The conclusion about which probe yields stronger bounds depends strongly on the mass ordering adopted, the absolute neutrino masses and which much decay one considers. In the 1-5 TeV mass region of the doubly charged scalar, lepton flavor violation experiments and colliders offer orthogonal and complementary probes. Thus if a signal is observed in one of the two new physics searches, the other will be able to assess whether it stems from a seesaw framework.

    hep-phEPJC(2019)·41 citations
15. 15*

    Self-interactions and Spontaneous Black Hole Scalarization

    Caio F. B. Macedo🇧🇷 · Jeremy Sakstein🇺🇸 · Emanuele Berti🇺🇸 · Leonardo Gualtieri🇮🇹 · Hector O. Silva🇺🇸 · Thomas P. Sotiriou🇬🇧

    It has recently been shown that nontrivial couplings between a scalar and the Gauss-Bonnet invariant can give rise to black hole spontaneous scalarization. Theories that exhibit this phenomenon are among the leading candidates for testing gravity with upcoming black hole observations. All models considered so far have focused on specific forms for the coupling, neglecting scalar self-interactions. In this work, we take the first steps towards placing this phenomenon on a more robust theoretical footing by considering the leading-order scalar self-interactions as well as the scalar-Gauss-Bonnet coupling. Our approach is consistent with the principles of effective field theory and yields the simplest and most natural model. We find that a mass term for the scalar alters the threshold for the onset of scalarization, and we study the mass range over which scalarized black hole solutions exist. We also demonstrate that the quartic self-coupling is sufficient to produce scalarized solutions that are stable against radial perturbations, without the need to resort to higher-order terms in the Gauss-Bonnet coupling function. Our model therefore represents a canonical model that can be studied further, with the ultimate aim of developing falsifiable tests of black hole scalarization.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2019)·171 citations
16. 16*

    Exploring A Cosmic-Ray Origin of the Multi-wavelength Emission in M31

    Alex McDaniel🇺🇸 · Tesla Jeltema🇺🇸 · Stefano Profumo🇺🇸

    A recent detection of spatially extended gamma-ray emission in the central region of the Andromeda galaxy (M31) has led to several possible explanations being put forth, including dark matter annihilation and millisecond pulsars. Another possibility is that the emission in M31 can be accounted for with a purely astrophysical cosmic-ray (CR) scenario. This scenario would lead to a rich multi-wavelength emission that can, in turn, be used to test it. Relativistic cosmic-ray electrons (CRe) in magnetic fields produce radio emission through synchrotron radiation, while X-rays and gamma rays are produced through inverse Compton scattering. Additionally, collisions of primary cosmic-ray protons (CRp) in the interstellar medium produce charged and neutral pions that then decay into secondary CRe (detectable through radiative processes) and gamma-rays. Here, we explore the viability of a CR origin for multi-wavelength emission in M31, taking into consideration three scenarios: a CR scenario dominated by primary CRe, one dominated by CRp and the resulting secondary CRe and gamma rays from neutral pion decay, and a final case in which both of these components exist simultaneously. We find that the multi-component model is the most promising, and is able to fit the multi-wavelength spectrum for a variety of astrophysical parameters consistent with previous studies of M31 and of cosmic-ray physics. However, the CR power injection implied by our models exceeds the estimated CR power injection from typical astrophysical cosmic-ray sources such as supernovae.

    ↳ astro-ph.HEastro-ph.GAhep-phPRD(2019)·24 citations
17. 17*

    Recent Results from the CERN LHC Experiment TOTEM -- Implications for Odderon Exchange

    T. Csörgő (for the TOTEM Collaboration)🇭🇺

    Recent results are summarized from the TOTEM experiment at CERN LHC, including measurements of the total, elastic and inelastic cross-sections, the nuclear slope parameter $B$, the differential cross-section of elastic scattering and the real to imaginary part ration $\rho$ at $\sqrt{s}=$ 2.76 and 13 TeV. The implications of these data for Odderon (odd-gluon colorless) exchange are discussed.

    ↳ hep-exhep-phnucl-exEPJ Web Conf.(2019)·12 citations
18. 18*

    An all-loop result for the strong magnetic field limit of the Heisenberg-Euler effective Lagrangian

    Felix Karbstein🇩🇪

    We provide an explicit expression for the strong magnetic field limit of the Heisenberg-Euler effective Lagrangian for both scalar and spinor quantum electrodynamics. To this end, we show that the strong magnetic field behavior is fully determined by one-particle reducible contributions discovered only recently. The latter can efficiently be constructed in an essentially algebraic procedure from lower-order one-particle reducible diagrams. Remarkably, the leading strong magnetic field behavior of the all-loop Heisenberg-Euler effective Lagrangian only requires input from the one-loop Lagrangian. Our result revises previous findings based exclusively on one-particle irreducible contributions. In addition we briefly discuss the strong electric field limit and comment on external field QED in the large $N$ limit.

    ↳ hep-thhep-phquant-phPRL(2019)·51 citations
19. 19*

    Effective field theory for black holes with induced scalar charges

    Leong Khim Wong🇬🇧 · Anne-Christine Davis🇬🇧 · Ruth Gregory🇬🇧

    While no-hair theorems forbid isolated black holes from possessing permanent moments beyond their mass, electric charge, and angular momentum, research over the past two decades has demonstrated that a black hole interacting with a time-dependent background scalar field will gain an induced scalar charge. In this paper, we study this phenomenon from an effective field theory (EFT) perspective. We employ a novel approach to constructing the effective point-particle action for the black hole by integrating out a set of composite operators localized on its worldline. This procedure, carried out using the in-in formalism, enables a systematic accounting of both conservative and dissipative effects associated with the black hole's horizon at the level of the action. We show that the induced scalar charge is inextricably linked to accretion of the background environment, as both effects stem from the same parent term in the effective action. The charge, in turn, implies that a black hole can radiate scalar waves and will also experience a "fifth force." Our EFT correctly reproduces known results in the literature for massless scalars, but now also generalizes to massive real scalar fields, allowing us to consider a wider range of scenarios of astrophysical interest. As an example, we use our EFT to study the early inspiral of a black hole binary embedded in a fuzzy dark matter halo.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2019)·38 citations
20. 20*

    Lunar Laser Ranging constraints on nonminimally coupled dark energy and standard sirens

    Shinji Tsujikawa🇯🇵

    In dark energy models where a scalar field $\varphi$ is coupled to the Ricci scalar $R$ of the form $e^{-2Q(\varphi -{\varphi }_0)/M_{\mathrm{pl}}}R$, where $Q$ is a coupling constant, ${\varphi }_0$ is today's value of $\varphi$, and $M_{\mathrm{pl}}$ is the reduced Planck mass, we study how the recent Lunar Laser Ranging (LLR) experiment places constraints on the nonminimal coupling from the time variation of gravitational coupling. Besides a potential of the light scalar responsible for cosmic acceleration, we take a cubic Galileon term into account to suppress fifth forces in over-density regions of the Universe. Even if the scalar-matter interaction is screened by the Vainshtein mechanism, the time variation of gravitational coupling induced by the cosmological background field $\varphi$ survives in the solar system. For a small Galileon coupling constant ${\beta }_3$, there exists a kinetically driven $\varphi$-matter-dominated-epoch ($\varphi$MDE) prior to cosmic acceleration. In this case, we obtain the stringent upper limit $Q\le 3.4\times 10^{-3}$ from the LLR constraint. For a large ${\beta }_3$ without the $\varphi$MDE, the coupling $Q$ is not particularly bounded from above, but the cosmological Vainshtein screening strongly suppresses the time variation of $\varphi$ such that the dark energy equation of state $w_{\mathrm{DE}}$ reaches the value close to $-1$ at high redshifts. We study the modified gravitational wave propagation induced by the nonminimal coupling to gravity and show that, under the LLR bound, the difference between the gravitational wave and luminosity distances does not exceed the order $10^{-5}$ over the redshift range $0<z<100$. In dark energy models where the Vainshtein mechanism is at work through scalar derivative self-interactions, it is difficult to probe the signature of nonminimal couplings from the observations of standard sirens.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2019)·24 citations
21. 21*

    Connecting direct and indirect detection with a dark spike in the cosmic-ray electron spectrum

    Adam Coogan🇳🇱 · Benjamin V. Lehmann🇺🇸 · Stefano Profumo🇺🇸

    Multiple space-borne cosmic ray detectors have detected line-like features in the electron and positron spectra. Most recently, the DAMPE collaboration reported the existence of such a feature at 1.4 TeV, sparking interest in a potential dark matter origin. Such quasi-monochromatic features, virtually free of any astrophysical background, could be explained by the annihilation of dark matter particles in a nearby dark matter clump. Here, we explore the consistency of producing such spectral features with dark matter annihilation from the standpoint of dark matter substructure statistics, constraints from anisotropy, and constraints from gamma-ray emission. We demonstrate that if indeed a high-energy, line-like feature in the electron-positron spectrum originates from dark matter annihilation in a nearby clump, a significant or even dominant fraction of the dark matter in the Solar System likely stems from the clump, with dramatic consequences for direct dark matter searches.

    ↳ astro-ph.HEastro-ph.GAhep-phJCAP(2019)·12 citations
22. 22*

    Background dynamics of pre-inflationary scenario in Brans-Dicke loop quantum cosmology

    Manabendra Sharma🇨🇳 · Tao Zhu🇨🇳 · Anzhong Wang🇺🇸

    Recently the background independent nonperturbative quantization technique has been extended to theories of gravity and the corresponding quantum effective cosmology has been derived, which provides us with necessary avenue to explore the pre-inflationary dynamics. Brans-Dicke loop quantum cosmology (BDLQC) is one such theory whose effective background dynamics is considered in this article. Starting with a quantum bounce, we explore the pre-inflationary dynamics of a universe sourced by a scalar field with the Starobinsky potential in BDLQC. Our study is based on the idea that though Einstein's and Jordan's frames are classically equivalent up to a conformal transformation in Brans-Dick theory, it is not true after quantization. Taking the Jordan frame as the physical one we explore in detail the bouncing scenario which is followed by a phase of slow roll inflation. The three phases of the evolution of the universe namely, bouncing, transition from quantum bounce to classical universe and the slow roll inflation, are noted for an initially kinetic energy dominated bounce. In addition, to be consistent with observational data, we also find out the allowed data space of initial conditions that would produce 60 e-folds of expansion during the slow roll inflation.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1Commun.Theor.Phys.(2019)·20 citations
23. 23*

    Neutron-mirror neutron oscillations for solving the puzzles of ultrahigh-energy cosmic rays

    Wanpeng Tan🇺🇸

    Based on a newly proposed mirror-matter model of neutron-mirror neutron ($n-n^{\prime }$) oscillations, the puzzles related to ultrahigh-energy cosmic rays (UHECRs) are explained. In particular, the phenomena around the Greisen-Zatsepin-Kuzmin (GZK) cutoff for UHECRs can be well understood under the new mirror matter model assuming a mirror-to-ordinary temperature ratio of $T^{\prime }/T\sim 0.3$. The suppression factor of the GZK effect due to the opacity of cosmic microwave background is calculated and agrees with the observations well. Most of the super-GZK events (i.e., above the GZK cutoff), as predicted in the new model, come from mirror matter sources that are invisible to electromagnetic telescopes and can penetrate the mirror cosmic microwave background at much further distances. Most remarkably, the anti-correlation between super-GZK and sub-GZK events in the hotspot observed by the Telescope Array (TA) collaboration can be naturally understood in this model. The possible correlations between the UHECRs from the TA hotspot and other nearby powerful sources such as high energy neutrinos detected by IceCube, the largest black hole merger (GW170729) observed by LIGO, and the hottest star-forming supercluster Lynx Arc, are discussed as well under the new theory.

    ↳ astro-ph.HEhep-ph9 citations
24. 24*

    On All-Order Higher-Point $\text{D}p$-$\overline{\text{D}p}$ Effective Actions

    Riccardo Antonelli🇮🇹 · Ivano Basile🇮🇹 · Ehsan Hatefi🇮🇹

    In this paper we derive a class of contributions to all orders in ${\alpha }^{\prime }$ to the effective action of D-brane-anti D-brane systems in Type II String Theory, considering an amplitude involving a closed-string Ramond-Ramond state and four open-string states: two tachyons, a scalar and a gauge boson. This type of amplitude arises in both Type IIA and Type IIB strings, and reveals a number of new effective couplings. Furthermore, we derive a series representation for the result that goes beyond a factorized limit that was recently studied, and which is expected to apply to more general six-point amplitudes of superstrings, including external fermions.

    ↳ hep-thhep-phmath-phmath.MPJCAP(2019)·5 citations
25. 25*

    Naive versus mirror assignment at finite density: correlator mixing and chiral symmetry restoration

    Boris Krippa🇬🇧

    Chiral symmetry imposes some constrains on hadron correlation functions in dense medium. These constraints imply a certain general structure of the two- and three-point correlation functions of chiral partners and lead to the effect of mixing arising from the interaction of the long-ranged nuclear pions with corresponding interpolating currents. It reflects the phenomena of partial restoration of chiral symmetry. We consider soft pion corrections for quark condensates and several possible pairs of chiral partners for both mesons and nucleons and analyse their mixing patterns. We explored both naive and mirror assignments for the chiral partner of nucleon and discussed possible phenomenological consequence.

    ↳ nucl-thhep-phJ.Phys.G(2020)·0 citations
26. 26*

    Runaway potentials and a massive goldstino

    Fotis Farakos🇧🇪

    We study N=1 globally supersymmetric theories on runaway backgrounds arising from scalar potentials with a slope characterized by a scale $M=|V/V^{\prime }|$. We find that, under mild assumptions, there always exists a massive goldstino in the low energy effective theory. In the simplest models the effective mass of such a fermion is of order $\sqrt{V}/M$, or of order $V/M^2\mu$ when a seesaw mechanism takes place, where $\mu$ is a scale that characterizes the masses of other heavy fermions.

    ↳ hep-thhep-phPRD(2019)·5 citations
27. 27*

    The twisted gradient flow coupling at one loop

    Eduardo I. Bribian🇪🇸 · Margarita Garcia Perez🇪🇸

    We compute the one-loop running of the $SU(N)$ 't Hooft coupling in a finite volume gradient flow scheme using twisted boundary conditions. The coupling is defined in terms of the energy density of the gradient flow fields at a scale $\tilde{l}$ given by an adequate combination of the torus size and the rank of the gauge group, and is computed in the continuum using dimensional regularization. We present the strategy to regulate the divergences for a generic twist tensor, and determine the matching to the $\overline{\mathrm{MS}}$ scheme at one-loop order. For the particular case in which the twist tensor is non-trivial in a single plane, we evaluate the matching coefficient numerically and determine the ratio of $\Lambda$ parameters between the two schemes. We analyze the $N$ dependence of the results and the possible implications for non-commutative gauge theories and volume independence.

    ↳ hep-lathep-phhep-thJHEP(2019)·26 citations

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