Thu·Sep 14, 2017Thursday·September 14, 2017

1. 01*

   Higher order string effects and the properties of the Pomeron

   Dmitri Kharzeev🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

   We revisit the description of the Pomeron within the effective string theory of QCD. Using a string duality relation, we show how the static potential maps onto the high-energy scattering amplitude that exhibits the Pomeron behavior. Besides the Pomeron intercept and slope, new additional terms stemming from the higher order string corrections are shown to affect both the growth of the nucleon's size at high energies and its profile in impact parameter space. The stringy description also allows for an odderon that only disappears in critical dimension. Some of the Pomeron's features that emerge within the effective string description can be studied at the future EIC collider.

   hep-phPRD(2018)·5 citations
2. 02*

   Exploring the supersymmetric U(1)${}_{B-L}\times$ U(1)${}_R$ model with dark matter, muon $g-2$ and $Z^{\prime }$ mass limits

   Mariana Frank🇨🇦 · Özer Özdal🇨🇦

   We study the low scale predictions of supersymmetric standard model extended by $U(1{)}_{B-L}\times U(1{)}_R$ symmetry, obtained from $SO(10)$ breaking via a left-right supersymmetric model, imposing universal boundary conditions. Two singlet Higgs fields are responsible for the radiative $U(1{)}_{B-L}\times U(1{)}_R$ symmetry breaking, and a singlet fermion $S$ is introduced to generate neutrino masses through inverse seesaw mechanism. The lightest neutralino or sneutrino emerge as dark matter candidates, with different low scale implications. We find that the composition of the neutralino LSP changes considerably depending on the neutralino LSP mass, from roughly half $U(1{)}_R$ bino, half MSSM bino, to singlet higgsino, or completely dominated by MSSM higgsino. The sneutrino LSP is statistically much less likely, and when it occurs it is a 50-50 mixture of right-handed sneutrino and the scalar $\tilde{S}$. Most of the solutions consistent with the relic density constraint survive the XENON 1T exclusion curve for both LSP cases. We compare the two scenarios and investigate parameter space points and find consistency with the muon anomalous magnetic moment only at the edge of $2\sigma$ deviation from the measured value. However, we find that the sneutrino LSP solutions could be ruled out completely by strict reinforcement of the recent $Z^{\prime }$ mass bounds. We finally discuss collider prospects for testing the model.

   hep-phPRD(2018)·10 citations
3. 03*

   Clockwork Higgs portal model for freeze-in dark matter

   Jinsu Kim🇰🇷 · John McDonald🇬🇧

   The clockwork mechanism can explain interactions which are dimensionally very weak without the need for very large mass scales. We present a model in which the clockwork mechanism generates the very small Higgs portal coupling and dark matter particle mass necessary to explain cold dark matter via the freeze-in mechanism. We introduce a TeV-scale scalar clockwork sector which couples to the Standard Model via the Higgs portal. The dark matter particle is the lightest scalar of the clockwork sector. We show that the freeze-in mechanism is dominated by decay of the heavy clockwork scalars to light dark matter scalars and Higgs bosons. In the model considered, we find that freeze-in dark matter is consistent with the clockwork mechanism for global charge $q$ in the range $2\lesssim q\lesssim 4$ when the number of massive scalars is in the range $10\le N\le 20$. The dark matter scalar mass and portal coupling are independent of $q$ and $N$. For a typical TeV-scale clockwork sector, the dark matter scalar mass is predicted to be of the order of a MeV.

   hep-phastro-ph.COhep-thPRD(2018)·40 citations
4. 04*

   Prompt photon production and photon-jet correlations at the LHC

   M. Klasen🇩🇪 · C. Klein-Bösing🇩🇪 · H. Poppenborg🇩🇪

   Next-to-leading order predictions matched to parton showers are compared with recent ATLAS data on inclusive photon production and CMS data on associated photon and jet production in pp and pPb collisions at different centre-of-mass energies of the LHC. We find good agreement and, as expected, considerably reduced scale uncertainties compared to previous theoretical calculations. Predictions are made for the ratio of inclusive photons over decay photons $R_{\gamma }$, an important quantity to evaluate the significance of additional photon sources, e.g. thermal radiation from a Quark-Gluon-Plasma, and for distributions in the parton momentum fraction in lead ions $x_{\mathrm{Pb}}^{\mathrm{obs}}$, that could be determined by ALICE, ATLAS, CMS and LHCb in ongoing analyses of photon+jet production in pPb collisions at $\sqrt{s_{NN}}=5.02$ TeV. These data should have an important impact on the determination of nuclear effects such as shadowing at low $x$.

   hep-phhep-exnucl-exnucl-thJHEP(2018)·34 citations
5. 05*

   Strong and radiative decays of the low-lying $S$- and $P$-wave singly heavy baryons

   Kai-Lei Wang🇨🇳 · Ya-Xiong Yao🇨🇳 · Xian-Hui Zhong🇨🇳 · Qiang Zhao🇨🇳

   The strong and radiative decays of the low-lying $S$- and $P$-wave ${\Lambda }_{c(b)}$, ${\Sigma }_{c(b)}$, ${\Xi }_{c(b)}$, ${\Xi }_{c(b)}^{\prime }$ and ${\Omega }_{c(b)}$ baryons are systematically studied in a constituent quark model. We find that the radiative decay mode ${\Lambda }_b^0\gamma$ could be very useful for us to establish the missing neutral states ${\Sigma }_b^0$ and ${\Sigma }_b^{\ast 0}$. Our calculation shows that most of those missing $\lambda$-mode $P$-wave singly heavy baryons have relatively narrow decay width of less than 30 MeV. Their dominant strong and radiative decay channels can be ideal for searching for their signals in future experiment. Configuration mixings between the $J^P=1/2^{-}$ states ${|}^2{P}_{\lambda }{\frac{1}{2}}^{-}⟩$ and ${|}^4{P}_{\lambda }{\frac{1}{2}}^{-}⟩$ of the $6_F$ multiplet are discussed. The ${\Xi }_c(2930{)}^0$ state seems to favor the mixed state $|{\Xi }_c^{\prime }{P}_{\lambda }{\frac{1}{2}}^{-}{⟩}_2$ with $J^P=1/2^{-}$. The ${\Sigma }_c(2800)$ resonance may be assigned to $|{\Sigma }_c{}^2{P}_{\lambda }{\frac{3}{2}}^{-}⟩$ with $J^P=3/2^{-}$ or $|{\Sigma }_c{}^4{P}_{\lambda }{\frac{5}{2}}^{-}⟩$ with $J^P=5/2^{-}$. In general, the excitations of ${|}^2{P}_{\lambda }{\frac{3}{2}}^{-}⟩$ and ${|}^4{P}_{\lambda }{\frac{5}{2}}^{-}⟩$ of the $6_F$ multiplet have similar strong decay properties. In order to to identify them, angular distributions of their decays in either strong decay modes or radiative transitions should be needed.

   hep-phhep-exnucl-thPRD(2017)·148 citations
6. 06*

   Sterile Neutrinos or Flux Uncertainties? - Status of the Reactor Anti-Neutrino Anomaly

   Mona Dentler🇩🇪 · Álvaro Hernández-Cabezudo🇩🇪 · Joachim Kopp🇩🇪 · Michele Maltoni🇪🇸 · Thomas Schwetz🇩🇪

   The $\sim 3\sigma$ discrepancy between the predicted and observed reactor anti-neutrino flux, known as the reactor anti-neutrino anomaly, continues to intrigue. The recent discovery of an unexpected bump in the reactor anti-neutrino spectrum, as well as indications that the flux deficit is different for different fission isotopes seems to disfavour the explanation of the anomaly in terms of sterile neutrino oscillations. We critically review this conclusion in view of all available data on electron (anti)neutrino disappearance. We find that the sterile neutrino hypothesis cannot be rejected based on global data and is only mildly disfavored compared to an individual rescaling of neutrino fluxes from different fission isotopes. The main reason for this is the presence of spectral features in recent data from the NEOS and DANSS experiments. If state-of-the-art predictions for reactor fluxes are taken at face value, sterile neutrino oscillations allow a consistent description of global data with a significance close to $3\sigma$ relative to the no-oscillation case. Even if reactor fluxes and spectra are left free in the fit, a $2\sigma$ hint in favour of sterile neutrinos remains, with allowed parameter regions consistent with an explanation of the anomaly in terms of oscillations.

   hep-phhep-exJHEP(2017)·109 citations
7. 07*

   NLO exclusive diffractive processes with saturation

   R. Boussarie🇵🇱 · A. V. Grabovsky🇷🇺 · D. Yu. Ivanov🇷🇺 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

   We present two NLO exclusive impact factors computed in the QCD shock wave approach. These are the very first steps towards precision studies of a wide range of high energy exclusive processes with saturation effects in $ep$, $eA$, $pp$ and $pA$ collisions.

   hep-phPoS(2018)·2 citations
8. 08*

   Central and peripheral interactions of hadrons

   I.M. Dremin🇷🇺 · V.A. Nechitailo🇷🇺 · S.N. White🇨🇭

   Surprisingly enough, the ratio of elastic to inelastic cross sections of proton interactions increases with energy in the interval correspond- ing to ISR - LHC (i.e. from 10 GeV to 10 TeV). That leads to special features of their spatial interaction region at these and higher ener- gies. Within the framework of some phenomenological models, we show how the particular ranges of the transferred momenta measured in elastic scattering experiments expose the spatial features of the in- elastic interaction region according to the unitarity condition. The difference between their predictions at higher energies is discussed. The notion of central and peripheral collisions of hadrons is treated in terms of the impact parameters description. It is shown that the shape of the differential cross section in the diffraction cone is mostly determined by collisions with intermediate impact parameters. Elastic scattering at very small transferred momenta is sensitive to peripheral processes with large impact parameters. The role of central collisions in formation of the diffraction cone is less significant.

   hep-phhep-exnucl-exnucl-thEPJC(2017)·9 citations
9. 09*

   Criticality in a Hadron Resonance Gas model with the van der Waals interaction

   Subhasis Samanta🇮🇳 · Bedangadas Mohanty🇮🇳

   The van der Waals interaction is implemented in a Hadron Resonance Gas model. It is shown that this model can describe Lattice QCD data of different thermodynamical quantities satisfactorily with the van der Waals parameters $a=1250\pm 150$ MeV fm${}^3$ and $r=0.7\pm 0.05$ fm. Further, a phase transition is observed in this model with the critical point at temperature, $T=62.1$ MeV and baryon chemical potential, ${\mu }_B=708$ MeV.

   hep-phnucl-thPRC(2018)·53 citations
10. 10*

    Phenomenology of $U(1{)}_F$ extension of inert-doublet model with exotic scalars and leptons

    Lobsang Dhargyal🇮🇳

    In this work we will extend the inert-doublet model (IDM) by adding a new $U(1{)}_F$ gauge symmetry to it, under which, a $Z_2$ even scalar (${\varphi }_2$) and $Z_2$ odd right handed component of two exotic charged leptons $(F_{eR},F_{\mu R})$, are charged. We also add one $Z_2$ even real scalar (${\varphi }_1$) and one complex scalar ($\varphi$), three neutral Majorana right handed fermions ($N_1,N_2,N_3$), two left handed components of the exotic charged leptons $(F_{eL},F_{\mu L})$ as well as $F_{\tau }$ are all odd under the $Z_2$, all of which are not charged under the $U(1{)}_F$. With these new particles added to the IDM, we have a model which can give two scalar DM candidates, together they can explain the present DM relic density as well as the muon (g-2) anomaly simultaneously. Also in this model the neutrino masses are generated at one loop level. One of the most peculiar feature of this model is that non-travail solution to the axial gauge anomaly free conditions lead to the prediction of a stable very heavy partner to the electron ($F_e$), whose present collider limit (14 TeV LHC) on its mass should be around $m_{F_e}\ge$ few TeV.

    hep-phEPJC(2018)·8 citations
11. 11*

    Jet Substructure at the Large Hadron Collider: A Review of Recent Advances in Theory and Machine Learning

    Andrew J. Larkoski🇺🇸 · Ian Moult🇺🇸 · Benjamin Nachman🇺🇸

    Jet substructure has emerged to play a central role at the Large Hadron Collider (LHC), where it has provided numerous innovative new ways to search for new physics and to probe the Standard Model in extreme regions of phase space. In this article we provide a comprehensive review of state of the art theoretical and machine learning developments in jet substructure. This article is meant both as a pedagogical introduction, covering the key physical principles underlying the calculation of jet substructure observables, the development of new observables, and cutting edge machine learning techniques for jet substructure, as well as a comprehensive reference for experts. We hope that it will prove a useful introduction to the exciting and rapidly developing field of jet substructure at the LHC.

    hep-phhep-exnucl-exnucl-thPhys.Rept.(2020)·695 citations
12. 12*

    Crack in the cosmological paradigm

    Eleonora Di Valentino🇫🇷

    A time-dependent dark energy component of the Universe may be able to explain tensions between local and primordial measurements of cosmological parameters, shaking current confidence in the concept of a cosmological constant.

    ↳ physics.pop-phastro-ph.COhep-phNature Astron.(2017)·73 citations
13. 13*

    Exploring the expansion dynamics of the universe from galaxy cluster surveys

    Deng Wang🇨🇳 · Xin-He Meng🇨🇳

    To understand the expansion dynamics of the universe from galaxy cluster scales, using the angular diameter distance (ADD) data from two different galaxy cluster surveys, we constrain four cosmological models to explore the underlying value of $H_0$ and employ the model-independent Gaussian Processes to investigate the evolution of the equation of state of dark energy. The ADD data in the X-ray bands consists of two samples covering the redshift ranges [0.023, 0.784] and [0.14, 0.89], respectively. We find that: (i) For these two samples, the obtained values of $H_0$ are more consistent with the recent local observation by Riess et al. than the global measurement by the Plank Collaboration, and the $\Lambda$CDM model is still preferred utilizing the information criterions; (ii) For the first sample, there is no evidence of dynamical dark energy (DDE) at the $2\sigma$ confidence level (CL); (iii) For the second one, the reconstructed equation of state of dark energy exhibits a phantom-crossing behavior in the relatively low redshift range over the $2\sigma$ CL, which gives a hint that the late-time universe may be actually dominated by the DDE from galaxy cluster scales; (iv) By adding a combination of Type Ia Supernovae, cosmic chronometers and Planck-2015 shift parameter and HII galaxy measurements into both ADD samples, the DDE exists evidently over the $2\sigma$ CL.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2017)·7 citations
14. 14*

    Finslerian Universe May Reconcile Tensions between High and Low Redshift Probes

    Deng Wang · Xin-He Meng

    To reconcile the current tensions between high and low redshift observations, we perform the first constraints on the Finslerian cosmological models including the effective dark matter and dark energy components. We find that all the four Finslerian models could alleviate effectively the Hubble constant ($H_0$) tension and the amplitude of the root-mean-square density fluctuations (${\sigma }_8$) tension between the Planck measurements and the local Universe observations at the 68$\%$ confidence level. The addition of a massless sterile neutrino and a varying total mass of active neutrinos to the base Finslerian two-parameter model, respectively, reduces the $H_0$ tension from $3.4\sigma$ to $1.9\sigma$ and alleviates the ${\sigma }_8$ tension better than the other three Finslerian models. Computing the Bayesian evidence, with respect to $\Lambda$CDM model, our analysis shows a weak preference for the base Finslerian model and moderate preferences for its three one-parameter extensions. Based on the model-independent Gaussian Processes, we propose a new linear relation which can describe the current redshift space distortions data very well. Using the most stringent constraints we can provide, we have also obtained the limits of typical model parameters for three one-parameter extensional models.

    ↳ astro-ph.COgr-qchep-phInt.J.Theor.Phys.(2023)·5 citations
15. 15*

    $\theta =\pi$ in $SU(N)/{\mathbb{Z}}_N$ gauge theories

    Ryuichiro Kitano🇯🇵 · Takao Suyama🇯🇵 · Norikazu Yamada🇯🇵

    In $SU(N)$ gauge theory, it is argued recently that there exists a "mixed anomaly" between the CP symmetry and the 1-form ${\mathbb{Z}}_N$ symmetry at $\theta =\pi$, and the anomaly matching requires CP to be spontaneously broken at $\theta =\pi$ if the system is in the confining phase. In this paper, we elaborate on this discussion by examining the large volume behavior of the partition functions of the $SU(N)/{\mathbb{Z}}_N$ theory on $T^4$ a la 't Hooft. The periodicity of the partition function in $\theta$, which is not $2\pi$ due to fractional instanton numbers, suggests the presence of a phase transition at $\theta =\pi$. We propose lattice simulations to study the distribution of the instanton number in $SU(N)/{\mathbb{Z}}_N$ theories. A characteristic shape of the distribution is predicted when the system is in the confining phase. The measurements of the distribution may be useful in understanding the phase structure of the theory.

    ↳ hep-thhep-lathep-phJHEP(2017)·35 citations
16. 16*

    Measurement of b quark EW couplings at ILC

    S. Bilokin🇫🇷 · R. Pöschl🇫🇷 · F. Richard🇫🇷

    This paper describes an analysis performed at 250 GeV centre of mass energy for the reaction e+e- -> bbbar with the International Linear Collider, ILC, assuming an integrated luminosity of 500 fb-1. This measurement requires determining the b quark charge, which can be optimally performed using the precise micro-vertex detector of the detector ILD and the charged kaon identification provided by the dE/dx information of its TPC. Given that the forward backward asymmetry is maximal for e-L (Left-handed electron polarisation), it has been necessary to develop a new method to correct for unavoidable angular migration due to b charge mis-measurements. This correction is based on the reconstructed events themselves without introducing external corrections which would induce large uncertainties. With polarized beams, one can separate the Z and photon vector and axial couplings to b quarks. The precision reached is at the few per mill level, and should allow to confirm/discard the deviation observed at LEP1 on the ZbRbR coupling. Model independent upper bounds on the tensor couplings, F2V and F2A, are derived using the shape of the angular distribution.

    ↳ hep-exhep-ph39 citations
17. 17*

    Pion distribution amplitude from Euclidean correlation functions

    Gunnar S. Bali🇩🇪 · Vladimir M. Braun🇩🇪 · Benjamin Gläßle🇩🇪 · Meinulf Göckeler🇩🇪 · Michael Gruber🇩🇪 · Fabian Hutzler🇩🇪 · Piotr Korcyl🇩🇪 · Bernhard Lang🇩🇪 · Andreas Schäfer🇩🇪 · Philipp Wein🇩🇪 · Jian-Hui Zhang🇩🇪

    Following the proposal in [1], we study the feasibility to calculate the pion distribution amplitude (DA) from suitably chosen Euclidean correlation functions at large momentum. In our lattice study we employ the novel momentum smearing technique [2,3]. This approach is complementary to the calculations of the lowest moments of the DA using the Wilson operator product expansion and avoids mixing with lower dimensional local operators on the lattice. The theoretical status of this method is similar to that of quasi-distributions [4], which has recently been applied to the same problem in [5]. The similarities and differences between these two techniques are highlighted.

    ↳ hep-lathep-phEPJC(2018)·98 citations
18. 18*

    Modified Dark Matter: Relating Dark Energy, Dark Matter and Baryonic Matter

    Douglas Edmonds🇺🇸 · Duncan Farrah🇺🇸 · Djordje Minic🇺🇸 · Y. Jack Ng🇺🇸 · Tatsu Takeuchi🇺🇸

    Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating Universe with positive cosmological constant ($\Lambda$), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to $\Lambda$. Such a critical acceleration is an effective phenomenological manifestation of MDM, and it is found in correlations between dark matter and baryonic matter in galaxy rotation curves. The resulting MDM mass profiles, which are sensitive to $\Lambda$, are consistent with observational data at both the galactic and cluster scales. In particular, the same critical acceleration appears both in the galactic and cluster data fits based on MDM. Furthermore, using some robust qualitative arguments, MDM appears to work well on cosmological scales, even though quantitative studies are still lacking. Finally, we comment on certain non-local aspects of the quanta of modified dark matter, which may lead to novel non-particle phenomenology and which may explain why, so far, dark matter detection experiments have failed to detect dark matter particles.

    ↳ astro-ph.COastro-ph.GAhep-phInt.J.Mod.Phys.D(2017)·29 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.