Thu·Mar 14, 2019Thursday·March 14, 2019

1. 01*

   The Z Penguin in Generic Extensions of the Standard Model

   Joachim Brod🇺🇸 · Martin Gorbahn🇬🇧

   Precision flavour observables play an important role in the interpretation of results at the LHC in terms of models of new physics. We present the result for the one-loop Z penguin in generic extensions of the standard model which exhibit exact perturbative unitarity. We use Slavnov-Taylor identities to study the implications of unitarity on the renormalisation of the Z penguin, and derive a manifestly finite result that depends on a reduced set of physical couplings.

   hep-phJHEP(2019)·12 citations
2. 02*

   A Unified No-Scale Model of Modulus Fixing, Inflation, Supersymmetry Breaking and Dark Energy

   John Ellis🇬🇧 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸 · Sarunas Verner🇺🇸

   We present a minimal SU(2,1)/SU(2) x U(1) no-scale model that incorporates in an economical way modulus fixing, Starobinsky-like inflation, an adjustable scale for supersymmetry breaking and the possibility of a small cosmological constant, a.k.a. dark energy.

   hep-phastro-ph.COgr-qchep-thPRD(2019)·18 citations
3. 03*

   T-odd anomalous interactions of the top-quark at the Large Hadron Collider

   Apurba Tiwari🇮🇳 · Sudhir Kumar Gupta🇮🇳

   We study the effects of T-odd interactions of top-quark via the pair production of top-quark in the semileptonic detection modes at the Large Hadron Collider by means of the T-odd observables constructed through the momenta of the observed decay products of the top (and anti-top)-quark for a wide range of CP-violating scale $\Lambda$. Estimates on the sensitivities of the coupling strength of such interactions for 13 TeV LHC energy with $\int \mathcal{L}dt$ = 36.1 fb${}^{-1}$, 140 fb${}^{-1}$ and for HL-LHC with 14 TeV energy with integrated luminosities of 0.3 ab${}^{-1}$, 1 ab${}^{-1}$, 2 ab${}^{-1}$ and 3 ab${}^{-1}$ are also presented for $\Lambda$ ranging between $M_W$ and 2 TeV.

   hep-phhep-exAdv.High Energy Phys.(2021)·8 citations
4. 04*

   On two-loop corrections to the Higgs trilinear coupling in models with extended scalar sectors

   Johannes Braathen🇯🇵 · Shinya Kanemura🇯🇵

   We investigate the possible size of two-loop radiative corrections to the Higgs trilinear coupling ${\lambda }_{hhh}$ in two types of models with extended Higgs sectors, namely in a Two-Higgs-Doublet Model (2HDM) and in the Inert Doublet Model (IDM). We calculate the leading contributions at two loops arising from the additional (heavy) scalars and the top quark of these theories in the effective-potential approximation. We include all necessary conversion shifts in order to obtain expressions both in the $\overline{\text{MS}}$ and on-shell renormalisation schemes, and in particular, we devise a consistent "on-shell" prescription for the soft-breaking mass of the 2HDM at the two-loop level. We illustrate our analytical results with numerical studies of simple aligned scenarios and show that the two-loop corrections to ${\lambda }_{hhh}$ remain smaller than their one-loop counterparts, with a typical size being 10-20% of the one-loop corrections, at least while perturbative unitarity conditions are fulfilled. As a consequence, the existence of a large deviation of the Higgs trilinear coupling from the prediction in the Standard Model, which has been discussed in the literature at one loop, is not altered significantly.

   hep-phPLB(2019)·87 citations
5. 05*

   Hunting for super-heavy dark matter with the highest-energy cosmic rays

   Esteban Alcantara🇺🇸 · Luis A. Anchordoqui🇺🇸 · Jorge F. Soriano🇺🇸

   In 15 years of data taking the Pierre Auger Observatory has observed no events beyond $10^{11.3}$ GeV. This null result translates into an upper bound on the flux of ultrahigh-energy cosmic rays implying $J(>10^{11.3}$ GeV) $<3.6\times 10^{-5}$ km${}^{-2}$ sr${}^{-1}$ yr${}^{-1}$, at the 90\%C.L. We interpret this bound as a constraint on extreme-energy photons originating in the decay super-heavy dark matter (SHDM) particles clustered in the Galactic halo. Armed with this constraint we derive the strongest lower limit on the lifetime of hadronically decaying SHDM particles with masses in the range, $10^{14}<M_X/$ GeV $<10^{15}$. We also explore the capability of future NASA's POEMMA mission to search for SHDM signals.

   hep-phastro-ph.HEPRD(2019)·49 citations
6. 06*

   Nucleon axial form factor from generalized parton distributions

   Hadi Hashamipour🇮🇷 · Muhammad Goharipour🇮🇷 · Siamak S. Gousheh🇮🇷

   It is well established that the nucleon form factors can be related to Generalized Parton Distributions (GPDs) through sum-rules. On the other hand, GPDs can be expressed in terms of Parton Distribution Functions (PDFs) according to Diehl's model. In this work, we use this model to calculate polarized GPDs for quarks (${\tilde{H}}_q$) using the available polarized PDFs obtained from the experimental data, and then study the axial form factor of nucleon. We determine parameters of the model using standard ${\chi }^2$ analysis of experimental data. It is shown that some parameters should be readjusted, as compared to some previously reported values, to obtain better consistency between the theoretical predictions and experimental data. Moreover, we study in details the uncertainty of nucleon axial form factor due to various sources.

   hep-phPRD(2019)·19 citations
7. 07*

   Deviations to Tri-Bi-Maximal mixing in the limit of $\mu -\tau$ symmetry

   Diana C. Rivera-Agudelo🇨🇴 · S. L. Tostado🇨🇴 · Abdel Pérez-Lorenzana🇲🇽

   In the limit of an approximate $\mu -\tau$ symmetry in the neutrino mass matrix, we explore deviations to the Tri-Bi-Maximal mixing pattern in the neutrino sector. We consider two different ansatzes for the corrected pattern to predict the current values of neutrino mixing parameters. We show that it is possible to constrain the Majorana $CP$ phases by studying their correlation to the mixing parameters and we study their effects on neutrinoless double beta decay observables. These predictions are sharp for the quasi-degenerate ordering and can be tested in upcoming experiments.

   hep-phPLB(2019)·6 citations
8. 08*

   Studying low-$x$ structure function models with astrophysical tau neutrinos: double bang, lollipop and sugardaddy topologies

   D. A. Fagundes🇧🇷 · R. R. Francisco🇧🇷 · E. G. de Oliveira🇧🇷

   Despite not have been yet identified by the IceCube detector, events generated from ${\nu }_{\tau }$ deep inelastic neutrino scattering in ice with varied topologies, such as double cascades (often called \textit{double bangs}), \textit{lollipops} and \textit{sugardaddies}, constitute a potential laboratory for low-x parton studies. Here we investigate these events, analyzing the effect of next-to-next-to-leading order (NNLO) Parton Distribution Function (PDFs) in the total neutrino--nucleon cross section, as compared with the color dipole formalism, where saturation effects play a major role. Energy deposit profiles in the `bangs' are also analysed in terms of virtual $W$-boson and tauon energy distributions and are found to be crucial in establishing a clear signal for gluon distribution determination at very small $x$. By taking the average (all flavor) neutrino flux (${\Phi }_{\nu }\sim E_{\nu }^{-2.3}$) into differential cross sections as a function of $\tau$ and $W$ energies, we find significant deviations from pure DGLAP parton interactions for neutrino energies already at a few PeV. With these findings one aims at providing not only possible observables to be measured in large volume neutrino detectors in the near future, but also theoretical ways of unraveling QCD dynamics using unintegrated neutrino-nucleon cross sections in the ultrahigh-energy frontier.

   hep-phastro-ph.HEPRD(2019)·3 citations
9. 09*

   Direct Detection and LHC constraints on a $t$-Channel Simplified Model of Majorana Dark Matter at One Loop

   Kirtimaan A. Mohan🇺🇸 · Dipan Sengupta🇺🇸 · Tim M.P Tait🇺🇸 · Bin Yan🇺🇸 · C.-P. Yuan🇺🇸

   An interesting class of models posits that the dark matter is a Majorana fermion which interacts with a quark together with a colored scalar mediator. Such a theory can be tested in direct detection experiments, through dark matter scattering with heavy nuclei, and at the LHC, via jets and missing energy signatures. Motivated by the fact that such theories have spin-independent interactions that vanish at tree level, we examine them at one loop (along with RGE improvement to resum large logs), and find that despite its occurrence at a higher order of perturbation theory, the spin-independent scattering searches typically impose the strongest constraints on the model parameter space. We further analyze the corresponding LHC constraints at one loop and find that it is important to take them into account when interpreting the implications of searches for jets plus missing momentum on this class of models, thus providing the corresponding complementary information for this class of models.

   hep-phhep-exJHEP(2019)·45 citations
10. 10*

    Model Independent analysis of MeV scale dark matter: I. Cosmological constraints

    Debajyoti Choudhury🇮🇳 · Divya Sachdeva🇮🇳

    Recent results from several direct detection experiments have imposed severe constraints on the multi-GeV mass window for various dark matter (DM) models. However, many of these experiments are not sensitive to MeV scale DM as the corresponding recoil energies are, largely, lower than the detector thresholds. We reexamine the light scalar DM in a model-independent approach. In this first of a two-part work, we develop an appropriate methodology to determine the effective coupling of such a DM to hadrons, thereby allowing for the determination of the corresponding annihilation rates. We find that while the parameter space can be constrained using cosmological and astrophysical observations, a significantly large fraction is still viable. In the companion paper, we study the sensitivity of both direct detection experiments as well as colliders to such a DM.

    hep-phPRD(2019)·15 citations
11. 11*

    Conservative dynamics of binary systems to fourth Post-Newtonian order in the EFT approach I: Regularized Lagrangian

    Stefano Foffa (Geneva U.)🇨🇭 · Riccardo Sturani (IIP, Natal)🇧🇷

    Within the framework of the effective field theory approach to the post-Newtonian approximation to General Relativity, we report the so far missing G^3 and G^4 sectors of the conservative two body dynamics at fourth perturbative order for non-spinning compact objects. Following the standard procedure, the exchange of gravitational interaction is integrated out to obtain a systematic expansion in terms of Feynman graphs. Building on this result and on previously obtained ones, we are able to write the local-in-time regularized Lagrangian at fourth post-Newtonian order, which is in agreement with results previously computed with other methods.

    ↳ gr-qchep-phhep-thPRD(2019)·152 citations
12. 12*

    Conservative dynamics of binary systems to fourth Post-Newtonian order in the EFT approach II: Renormalized Lagrangian

    Stefano Foffa🇨🇭 · Rafael A. Porto🇩🇪 · Ira Rothstein🇺🇸 · Riccardo Sturani🇧🇷

    We complete the derivation of the conservative dynamics of binary systems to fourth Post-Newtonian (4PN) order in the effective field theory (EFT) approach. We present a self-contained (ambiguity-free) computation of the renormalized Lagrangian, entirely within the confines of the PN expansion. While we confirm the final results reported in the literature, we clarify several issues regarding intermediate infrared (IR) and ultraviolet (UV) divergences, as well as the renormalization procedure. First, we properly identify the IR and UV singularities using (only) dimensional regularization and the method of regions, which are the pillars of the EFT formalism. This requires a careful study of scaleless integrals in the potential region, as well as conservative contributions from radiation modes due to tail effects. As expected by consistency, the UV divergences in the near region (due to the point-particle limit) can be absorbed into two counter-terms in the worldline effective theory. The counter-terms can then be removed by field redefinitions, such that the renormalization scheme-dependence has no physical effect to 4PN order. The remaining IR poles, which are spurious in nature, are unambiguously removed by implementing the zero-bin subtraction in the EFT approach. The procedure transforms the IR singularities into UV counter-parts. As anticipated, the left-over UV poles explicitly cancel out against UV divergences in conservative terms from radiation-reaction, uniquely determining the gravitational potential. Similar artificial IR/UV poles, which are intimately linked to the split into regions, are manifest at lower orders. Starting at 4PN, both local- and nonlocal-in-time contributions from the radiation region enter in the conservative dynamics. Neither additional regulators nor ambiguity-parameters are introduced at any stage of the computations.

    ↳ gr-qchep-phhep-thPRD(2019)·205 citations
13. 13*

    Resonant Reconciliation of Convex Models and the Planck

    Ali Akbar Abolhasani🇮🇷 · M. M. Sheikh-Jabbari🇮🇷

    We consider single field chaotic inflationary models plus a cosine modulation term, as in axion monodromy models, and augment it by a light scalar field with similar cosine coupling. We show the power spectrum of curvature perturbations of this model is dominated by the one-loop contribution to inflaton two-point function which is enhanced due to resonant interactions. This allows to disentangle the scale of scalar and tensor perturbations and hence to suppress the ratio of tensor-to-scalar power spectra and alters the expression of scalar spectral tilt from the simple chaotic models, thus opening the way to reconcile chaotic models with convex potential and the Planck data. As in monodromy inflation models, we also have a cosine modulation in spectral tilt. We mention that contribution of resonance effects on non-Gaussianty is small and it remains within the current bounds. Resonant production of light particles toward the end of inflation may set the stage for a successful reheating model.

    ↳ astro-ph.COhep-phhep-thPRD(2019)·10 citations
14. 14*

    Energy-energy correlations at next-to-next-to-leading order

    Johannes M. Henn🇩🇪 · Emery Sokatchev🇫🇷 · Kai Yan🇩🇪 · Alexander Zhiboedov🇨🇭

    We develop further an approach to computing energy-energy correlations (EEC) directly from finite correlation functions. In this way, one completely avoids infrared divergences. In maximally supersymmetric Yang-Mills theory ($\mathcal{N}=4$ sYM), we derive a new, extremely simple formula relating the EEC to a triple discontinuity of a four-point correlation function. We use this formula to compute the EEC in $\mathcal{N}=4$ sYM at next-to-next-to-leading order in perturbation theory. Our result is given by a two-fold integral representation that is straightforwardly evaluated numerically. We find that some of the integration kernels are equivalent to those appearing in sunrise Feynman integrals, which evaluate to elliptic functions. Finally, we use the new formula to provide the expansion of the EEC in the back-to-back and collinear limits.

    ↳ hep-thhep-phPRD(2019)·100 citations
15. 15*

    Charged and neutral fixed points in the O(N)+O(N)-model with Abelian gauge fields

    Aron J. Beekman🇯🇵 · Gergely Fejős🇯🇵

    In the Abelian-Higgs model, or Ginzburg-Landau model of superconductivity, the existence of an infrared stable charged fixed point ensures that there is a parameter range where the superconducting phase transition is second order, as opposed to fluctuation-induced first order as one would infer from the Coleman-Weinberg mechanism. We study the charged and neutral fixed points of a two-field generalization of the Abelian-Higgs model, where two N-component fields are coupled to two gauge fields and to each other, using the functional renormalization group. Focusing mostly on three dimensions, in the neutral case, this is a model for two-component Bose-Einstein condensation, and we confirm the fixed-point structure established in earlier works using different methods. The charged model is a dual theory of two-dimensional dislocation-mediated quantum melting. We find the existence of three charged fixed points for all N>2, while there are additional fixed points for N=2.

    ↳ hep-thcond-mat.stat-mechhep-phPRD(2019)·2 citations
16. 16*

    Collision energy dependence of second-order off-diagonal and diagonal cumulants of net-charge, net-proton and net-kaon multiplicity distributions in Au+Au collisions

    STAR Collaboration: J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · R. Aoyama · A. Aparin · D. Arkhipkin and 335 other authors

    We report the first measurements of a complete second-order cumulant matrix of net-charge, net-proton, and net-kaon multiplicity distributions for the first phase of the beam energy scan program at RHIC. This includes the centrality and, for the first time, the pseudorapidity window dependence of both diagonal and off-diagonal cumulants in Au+Au collisions at \sNN~= 7.7-200 GeV. Within the available acceptance of $|\eta |<0.5$, the cumulants grow linearly with the pseudorapidity window. Relative to the corresponding measurements in peripheral collisions, the ratio of off-diagonal over diagonal cumulants in central collisions indicates an excess correlation between net-charge and net-kaon, as well as between net-charge and net-proton. The strength of such excess correlation increases with the collision energy. The correlation between net-proton and net-kaon multiplicity distributions is observed to be negative at \sNN~= 200 GeV and change to positive at the lowest collision energy. Model calculations based on non-thermal (UrQMD) and thermal (HRG) production of hadrons cannot explain the data. These measurements will help map the QCD phase diagram, constrain hadron resonance gas model calculations, and provide new insights on the energy dependence of baryon-strangeness correlations. An erratum has been added to address the issue of self-correlation in the previously considered efficiency correction for off-diagonal cumulant measurement. Previously considered unidentified (net-)charge correlation results (${\sigma }_{Q,p}^{11}$ and ${\sigma }_{Q,k}^{11})$ are now replaced with identified (net-)charge correlation (${\sigma }_{Q^{PID},p}^{11}$ and ${\sigma }_{Q^{PID},k}^{11}$)

    ↳ nucl-exhep-exhep-phPRC(2019)·63 citations
17. 17*

    Estimates of hyperon polarization in heavy-ion collisions at collision energies $\sqrt{s_{NN}}=$ 4--40 GeV

    Yu. B. Ivanov🇷🇺 · V. D. Toneev🇷🇺 · A. A. Soldatov🇷🇺

    Global polarization of $\Lambda$ and $\bar{\Lambda }$ hyperons in Au+Au collisions at collision energies $\sqrt{s_{NN}}=$ 4-40 GeV in the midrapidity region and total polarization, i.e. averaged over all rapidities, are studied within the scope of the thermodynamical approach. The relevant vorticity is simulated within the model of the three-fluid dynamics (3FD). It is found that the performed rough estimate of the global midrapidity polarization quite satisfactorily reproduces the experimental STAR data on the polarization, especially its collision-energy dependence. The total polarization increases with the collision energy rise, which is in contrast to the decrease of the midrapidity polarization. This suggests that at high collision energies the polarization reaches high values in fragmentation regions.

    ↳ nucl-thhep-phnucl-exPRC(2019)·72 citations
18. 18*

    High Precision Measurement of Compton Scattering in the 5 GeV region

    P. Ambrozewicz🇺🇸 · L. Ye🇺🇸 · Y. Prok🇺🇸 · I. Larin🇷🇺 · A. Ahmidouch🇺🇸 · K. Baker🇺🇸 · V. Baturin🇺🇸 · L. Benton🇺🇸 · A. Bernstein🇺🇸 · V. Burkert🇺🇸 · E. Clinton🇺🇸 · P.L. Cole🇺🇸 and 85 other authors

    The cross section of atomic electron Compton scattering $\gamma +e\to {\gamma }^{\prime }+e^{\prime }$ was measured in the 4.40--5.475 GeV photon beam energy region by the {\em PrimEx} collaboration at Jefferson Lab with an accuracy of 2\% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV.

    ↳ nucl-exhep-phnucl-thPLB(2019)·6 citations
19. 19*

    Fate of the ${\eta }^{\prime }$ in the Quark Gluon Plasma

    Andrey Yu. Kotov🇷🇺 · Maria Paola Lombardo🇮🇹 · Anton M. Trunin🇷🇺

    In this paper we study the ${\eta }^{\prime }$ in $N_f=2+1+1$ lattice QCD simulations at finite temperature. Results are obtained from the analysis of the gluonic defined topological charge density correlator after gradient flow. Our results indicate the growth of the ${\eta }^{\prime }$ mass above the pseudocritical temperature, associated with the chiral symmetry restoration. In the vicinity of the pseudocritical temperature the results are consistent with a small dip in the ${\eta }^{\prime }$ mass. The magnitude of the dip is compatible with the reduction of the ${\eta }^{\prime }$ mass obtained by experimental analysis and suggests that ${\eta }^{\prime }$ mass comes close to zero temperature non-anomalous contribution.

    ↳ hep-lathep-phPLB(2019)·19 citations
20. 20*

    Detection of a $\gamma$-ray halo around Geminga with the Fermi-LAT and implications for the positron flux

    Mattia Di Mauro🇺🇸 · Silvia Manconi🇮🇹 · Fiorenza Donato🇮🇹

    The HAWC Collaboration has discovered a $\gamma$-ray emission extended about 2 degrees around the Geminga and Monogem pulsar wind nebulae (PWNe) at $\gamma$-ray energies $E_{\gamma }>5$ TeV. We analyze, for the first time, almost 10 years of $\gamma$-ray data obtained with the Fermi Large Area Telescope at $E_{\gamma }>$ 8 GeV in the direction of Geminga and Monogem. Since these two pulsars are close the Galactic plane we run our analysis with 10 different interstellar emission models (IEMs) to study the systematics due to the modeling of this component. We detect a $\gamma$-ray halo around Geminga with a significance in the range $7.8-11.8\sigma$ depending on the IEM considered. This measurement is compatible with $e^{+}$ and $e^{-}$ emitted by the PWN, which inverse-Compton scatter (ICS) with photon fields located within a distance of about 100 pc from the pulsar, where the diffusion coefficient is estimated to be around $1.1\times 10^{27}$ cm${}^2$/s at 100 GeV. We include in our analysis the proper motion of the Geminga pulsar which is relevant for $\gamma$ rays produced for ICS in the Fermi-LAT energy range. We find that an efficiency of about $1\%$ for the conversion of the spin-down energy of the pulsar into $e^{+}$ and $e^{-}$ is required to be consistent with $\gamma$-ray data from Fermi-LAT and HAWC. The inferred contribution of Geminga to the $e^{+}$ flux is at most $20\%$ at the highest energy AMS-02 data. Our results are compatible with the interpretation that the cumulative emission from Galactic pulsars explains the positron excess.

    ↳ astro-ph.HEastro-ph.GAhep-phPRD(2019)·145 citations
21. 21*

    Magnetars as Astrophysical Laboratories of Extreme Quantum Electrodynamics: The Case for a Compton Telescope

    Zorawar Wadiasingh🇺🇸 · George Younes🇺🇸 · Matthew G. Baring🇺🇸 · Alice K. Harding🇺🇸 · Peter L. Gonthier🇺🇸 · Kun Hu🇺🇸 · Alexander van der Horst🇺🇸 · Silvia Zane🇬🇧 · Chryssa Kouveliotou🇺🇸 · Andrei M. Beloborodov🇺🇸 · Chanda Prescod-Weinstein🇺🇸 · Tanmoy Chattopadhyay🇺🇸 and 5 other authors

    A next generation of Compton and pair telescopes that improve MeV-band detection sensitivity by more than a decade beyond current instrumental capabilities will open up new insights into a variety of astrophysical source classes. Among these are magnetars, the most highly magnetic of the neutron star zoo, which will serve as a prime science target for a new mission surveying the MeV window. This paper outlines the core questions pertaining to magnetars that can be addressed by such a technology. These range from global magnetar geometry and population trends, to incisive probes of hard X-ray emission locales, to providing cosmic laboratories for spectral and polarimetric testing of exotic predictions of QED, principally the prediction of the splitting of photons and magnetic pair creation. Such fundamental physics cannot yet be discerned in terrestrial experiments. State of the art modeling of the persistent hard X-ray tail emission in magnetars is presented to outline the case for powerful diagnostics using Compton polarimeters. The case highlights an inter-disciplinary opportunity to seed discovery at the interface between astronomy and physics.

    ↳ astro-ph.HEhep-ph14 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.