Fri·Jul 21, 2017Friday·July 21, 2017

1. 01*

   WIMP dark matter candidates and searches - current status and future prospects

   Leszek Roszkowski🇵🇱 · Enrico Maria Sessolo🇵🇱 · Sebastian Trojanowski🇺🇸

   We review several current aspects of dark matter theory and experiment. We overview the present experimental status, which includes current bounds and recent claims and hints of a possible signal in a wide range of experiments: direct detection in underground laboratories, gamma-ray, cosmic ray, X-ray, neutrino telescopes, and the LHC. We briefly review several possible particle candidates for a Weakly Interactive Massive Particle (WIMP) and dark matter that have recently been considered in the literature. We pay particular attention to the lightest neutralino of supersymmetry as it remains the best motivated candidate for dark matter and also shows excellent detection prospects. Finally we briefly review some alternative scenarios that can considerably alter properties and prospects for the detection of dark matter obtained within the standard thermal WIMP paradigm.

   hep-phastro-ph.CORept.Prog.Phys.(2018)·909 citations
2. 02*

   Light Axinos from Freeze-in: production processes, phase space distributions, and Ly-$\alpha$ forest constraints

   Kyu Jung Bae🇰🇷 · Ayuki Kamada🇰🇷 · Seng Pei Liew🇩🇪 · Keisuke Yanagi🇯🇵

   We consider freeze-in production of 7 keV axino dark matter (DM) in the supersymmetric Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) model in light of the 3.5 keV line excess. The warmness of such 7 keV DM produced from the thermal bath, in general, appears in tension with Ly-$\alpha$ forest data, although a direct comparison is not straightforward. This is because the Ly-$\alpha$ forest constraints are usually reported on the mass of the conventional warm dark matter (WDM), where large entropy production is implicitly assumed to occur in the thermal bath after WDM particles decouple. The phase space distribution of freeze-in axino DM varies depending on production processes and axino DM may alleviate the tension with the tight Ly-$\alpha$ forest constraints. By solving the Boltzmann equation, we first obtain the resultant phase space distribution of axinos produced by 2-body decay, 3-body decay, and 2-to-2 scattering, respectively. The reduced collision term and resultant phase space distribution are useful for studying other freeze-in scenarios as well. We then calculate the resultant linear matter power spectra for such axino DM and directly compare them with the linear matter power spectra for the conventional WDM. In order to demonstrate realistic axino DM production, we consider benchmark points with the Higgsino next-to-lightest supersymmetric particle (NLSP) and wino NLSP. In the case of the Higgsino NLSP, the phase space distribution of axinos is colder than that in the conventional WDM case, so the most stringent Ly-$\alpha$ forest constraint can be evaded with mild entropy production from saxion decay inherent in the supersymmetric DFSZ axion model.

   hep-phastro-ph.COJCAP(2018)·67 citations
3. 03*

   FORM version 4.2

   Ben Ruijl🇳🇱 · Takahiro Ueda🇳🇱 · Jos Vermaseren🇳🇱

   We introduce FORM 4.2, a new minor release of the symbolic manipulation toolkit. We demonstrate several new features, such as a new pattern matching option, new output optimization, and automatic expansion of rational functions.

   hep-phcs.SC428 citations
4. 04*

   Systematic Studies of Exact $\mathcal{O}({\alpha }^{2}L)$ CEEX EW Corrections in a Hadronic MC for Precision $Z/{\gamma }^{\ast }$ Physics at LHC Energies

   S. Jadach (1)🇵🇱 · B.F.L. Ward (2)🇺🇸 · Z. A. Was (1)🇵🇱 · S. A. Yost (3) ((1) Institute of Nuclear Physics Polish Academy of Sciences, Cracow, PL, (2) Baylor University, Waco, TX, USA, (3) The Citadel, Charleston, SC, USA)🇺🇸

   With an eye toward the precision physics of the LHC, such as the recent measurement of $M_W$ by the ATLAS Collaboration, we present here systematic studies relevant to the assessment of the expected size of multiple photon radiative effects in heavy gauge boson production with decay to charged lepton pairs. We use the new version 4.22 of $\mathcal{KK}$MC-hh so that we have CEEX EW exact $\mathcal{O}({\alpha }^{2}L)$ corrections in a hadronic MC and control over the corresponding EW initial-final interference (IFI) effects as well. In this way, we illustrate the interplay between cuts of the type used in the measurement of $M_W$ at the LHC and the sizes of the expected responses of the attendant higher order corrections. We find that there are per cent to per mille level effects in the initial-state radiation, fractional per mille level effects in the IFI and per mille level effects in the over-all $\mathcal{O}({\alpha }^{2}L)$ corrections that any treatment of EW corrections at the per mille level should consider. Our results have direct applicability to current LHC experimental data analyses.

   hep-phPRD(2019)·35 citations
5. 05*

   Meson exchange in lepton-nucleon scattering and proton radius puzzle

   Dmitry Borisyuk🇺🇦

   We study two-photon contribution to the elastic lepton-proton scattering, associated with sigma meson exchange, with special attention paid to the low-Q2 region. We show that the corresponding amplitude grows sharply but remains finite at Q2->0. The analytical formula for the amplitude at Q2=0 is obtained. We also estimate the shift of the muonic hydrogen energy levels, induced by sigma meson exchange. For the 2S level the shift is approximately 30 times smaller than needed to resolve the proton radius puzzle, but still exceeds the precision of the muonic hydrogen measurements.

   hep-phPRC(2017)·13 citations
6. 06*

   Light flavon signals at electron - photon colliders

   Yu Muramatsu🇨🇳 · Takaaki Nomura🇰🇷 · Yusuke Shimizu🇯🇵 · Hiroshi Yokoya🇰🇷

   Flavor symmetries are useful to realize fermion flavor structures in the standard model. In particular, discrete $A_4$ symmetry is used to realize lepton flavor structures, and some scalars which are called flavon are introduced to break this symmetry. In many models, flavons are assumed to be much heavier than the electroweak scale. However, our previous work showed that flavon mass around 100 GeV is allowed by experimental constraints in the $A_4$ symmetric model with residual $Z_3$ symmetry. In this paper, we discuss collider search of such a light flavon ${\phi }_T$. We find that an electron - photon collision, as a considerable option at the international linear collider, has advantages to search for the signals. At the electron - photon collider flavons are produced as $e^{-}\gamma \to l^{-}{\phi }_T$ and decay into two charged leptons. Then we analyze signals of flavor-conserving final-state ${\tau }^{+}{\tau }^{-}{e}^{-}$, and flavor-violating final-states ${\tau }^{+}{\mu }^{-}{\mu }^{-}$ and ${\mu }^{+}{\tau }^{-}{\tau }^{-}$ by carrying out numerical simulation. For the former final-state, SM background can be strongly suppressed by imposing cuts on the invariant masses of final-state leptons. For the later final-states, SM background is extremely small, because in the SM there are no such flavor-violating final-states. We then find that sufficient discovery significance can be obtained, even if flavons are heavier than the lower limits from flavor physics.

   hep-phhep-exPRD(2018)·7 citations
7. 07*

   Weak Decays of Doubly Heavy Baryons: SU(3) Analysis

   Wei Wang🇨🇳 · Zhi-Peng Xing🇨🇳 · Ji Xu🇨🇳

   Motivated by the recent LHCb observation of doubly-charmed baryon ${\Xi }_{cc}^{++}$ in the ${\Lambda }_c^{+}{K}^{-}{\pi }^{+}{\pi }^{+}$ final state, we analyze the weak decays of doubly heavy baryons ${\Xi }_{cc}$, ${\Omega }_{cc}$, ${\Xi }_{bc}$, ${\Omega }_{bc}$, ${\Xi }_{bb}$ and ${\Omega }_{bb}$ under the flavor SU(3) symmetry. Decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover once a few decay branching fractions are measured in future, some of these relations may provide hints for exploration of new decay modes.

   hep-phhep-exEPJC(2017)·135 citations
8. 08*

   Inflation and Dark Matter in the Inert Doublet Model

   Sandhya Choubey🇮🇳 · Abhass Kumar🇮🇳

   We discuss inflation and dark matter in the inert doublet model coupled non-minimally to gravity where the inert doublet is the inflaton and the neutral scalar part of the doublet is the dark matter candidate. We calculate the various inflationary parameters like $n_s$, $r$ and $P_s$ and then proceed to the reheating phase where the inflaton decays into the Higgs and other gauge bosons which are non-relativistic owing to high effective masses. These bosons further decay or annihilate to give relativistic fermions which are finally responsible for reheating the universe. At the end of the reheating phase, the inert doublet which was the inflaton enters into thermal equilibrium with the rest of the plasma and its neutral component later freezes out as cold dark matter with a mass of about 2 TeV.

   hep-phastro-ph.COJHEP(2017)·53 citations
9. 09*

   Quark matter may not be strange

   Bob Holdom🇨🇦 · Jing Ren🇨🇦 · Chen Zhang🇨🇦

   If quark matter is energetically favored over nuclear matter at zero temperature and pressure then it has long been expected to take the form of strange quark matter (SQM), with comparable amounts of $u$, $d$, $s$ quarks. The possibility of quark matter with only $u$, $d$ quarks ($ud$QM) is usually dismissed because of the observed stability of ordinary nuclei. However we find that $ud$QM generally has lower bulk energy per baryon than normal nuclei and SQM. This emerges in a phenomenological model that describes the spectra of the lightest pseudoscalar and scalar meson nonets. Taking into account the finite size effects, $ud$QM can be the ground state of baryonic matter only for baryon number $A>A_{\text{min}}$ with $A_{\text{min}}\gtrsim 300$. This ensures the stability of ordinary nuclei and points to a new form of stable matter just beyond the periodic table.

   hep-phPRL(2018)·148 citations
10. 10*

    Framework for an asymptotically safe Standard Model via dynamical breaking

    Steven Abel🇬🇧 · Francesco Sannino🇩🇰

    We present a consistent embedding of the matter and gauge content of the Standard Model into an underlying asymptotically-safe theory, that has a well-determined in- teracting UV fixed point in the large colour/flavour limit. The scales of symmetry breaking are determined by two mass-squared parameters with the breaking of elec- troweak symmetry being driven radiatively. There are no other free parameters in the theory apart from gauge couplings.

    hep-phhep-lathep-thPRD(2017)·37 citations
11. 11*

    Study of the Question of an Ultraviolet Zero in the Six-Loop Beta Function of the O($N$) $\lambda |\vec{\varphi }{|}^4$ Theory

    Robert Shrock🇺🇸

    We study the possibility of an ultraviolet (UV) zero in the six-loop beta function of an O($N$) $\lambda |\vec{\varphi }{|}^4$ field theory in $d=4$ spacetime dimensions. For general $N$, in the range of values of $\lambda$ where a perturbative calculation is reliable, we find evidence against such a UV zero in this six-loop beta function.

    ↳ hep-thhep-lathep-phPRD(2017)·8 citations
12. 12*

    Dark matter spikes in the vicinity of Kerr black holes

    Francesc Ferrer🇺🇸 · Augusto Medeiros da Rosa🇺🇸 · Clifford M. Will🇺🇸

    The growth of a massive black hole will steepen the cold dark matter density at the center of a galaxy into a dense spike, enhancing the prospects for indirect detection. We study the impact of black hole spin on the density profile using the exact Kerr geometry of the black whole in a fully relativistic adiabatic growth framework. We find that, despite the transfer of angular momentum from the hole to the halo, rotation increases significantly the dark matter density close to the black hole. The gravitational effects are still dominated by the black hole within its influence radius, but the larger dark matter annihilation fluxes might be relevant for indirect detection estimates.

    ↳ astro-ph.COgr-qchep-phPRD(2017)·121 citations
13. 13*

    Rigorous constraints on the matrix elements of the energy-momentum tensor

    Peter Lowdon🇺🇸 · Kelly Yu-Ju Chiu🇺🇸 · Stanley J. Brodsky🇺🇸

    The structure of the matrix elements of the energy-momentum tensor play an important role in determining the properties of the form factors $A(q^2)$, $B(q^2)$ and $C(q^2)$ which appear in the Lorentz covariant decomposition of the matrix elements. In this paper we apply a rigorous frame-independent distributional-matching approach to the matrix elements of the Poincaré generators in order to derive constraints on these form factors as $q\to 0$. In contrast to the literature, we explicitly demonstrate that the vanishing of the anomalous gravitomagnetic moment $B(0)$ and the condition $A(0)=1$ are independent of one another, and that these constraints are not related to the specific properties or conservation of the individual Poincaré generators themselves, but are in fact a consequence of the physical on-shell requirement of the states in the matrix elements and the manner in which these states transform under Poincaré transformations.

    ↳ hep-thhep-phnucl-thPLB(2017)·46 citations
14. 14*

    Weak Gravity Conjecture, Multiple Point Principle and the Standard Model Landscape

    Yuta Hamada🇯🇵 · Gary Shiu🇺🇸

    The requirement for an ultraviolet completable theory to be well-behaved upon compactification has been suggested as a guiding principle for distinguishing the landscape from the swampland. Motivated by the weak gravity conjecture and the multiple point principle, we investigate the vacuum structure of the standard model compactified on $S^1$ and $T^2$. The measured value of the Higgs mass implies, in addition to the electroweak vacuum, the existence of a new vacuum where the Higgs field value is around the Planck scale. We explore two- and three-dimensional critical points of the moduli potential arising from compactifications of the electroweak vacuum as well as this high scale vacuum, in the presence of Majorana/Dirac neutrinos and/or axions. We point out potential sources of instability for these lower dimensional critical points in the standard model landscape. We also point out that a high scale $Ad{S}_4$ vacuum of the Standard Model, if exists, would be at odd with the conjecture that all non-supersymmetric $AdS$ vacua are unstable. We argue that, if we require a degeneracy between three- and four-dimensional vacua as suggested by the multiple point principle, the neutrinos are predicted to be Dirac, with the mass of the lightest neutrino O(1-10) meV, which may be tested by future CMB, large scale structure and $21$cm line observations.

    ↳ hep-thhep-phJHEP(2017)·66 citations
15. 15*

    Model-Independent Constraints on Lorentz Invariance Violation via the Cosmographic Approach

    Xiao-Bo Zou🇨🇳 · Hua-Kai Deng🇨🇳 · Zhao-Yu Yin🇨🇳 · Hao Wei🇨🇳

    Since Lorentz invariance plays an important role in modern physics, it is of interest to test the possible Lorentz invariance violation (LIV). The time-lag (the arrival time delay between light curves in different energy bands) of Gamma-ray bursts (GRBs) has been extensively used to this end. However, to our best knowledge, one or more particular cosmological models were assumed {\it a priori} in (almost) all of the relevant works in the literature. So, this makes the results on LIV in those works model-dependent and hence not so robust in fact. In the present work, we try to avoid this problem by using a model-independent approach. We calculate the time delay induced by LIV with the cosmic expansion history given in terms of cosmography, without assuming any particular cosmological model. Then, we constrain the possible LIV with the observational data, and find weak hints for LIV.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1PLB(2018)·38 citations
16. 16*

    Supernova Signatures of Neutrino Mass Ordering

    Kate Scholberg🇺🇸

    A suite of detectors around the world is poised to measure the flavor-energy-time evolution of the ten-second burst of neutrinos from a core-collapse supernova occurring in the Milky Way or nearby. Next-generation detectors to be built in the next decade will have enhanced flavor sensitivity and statistics. Not only will the observation of this burst allow us to peer inside the dense matter of the extreme event and learn about the collapse processes and the birth of the remnant, but the neutrinos will bring information about neutrino properties themselves. This review surveys some of the physical signatures that the currently-unknown neutrino mass pattern will imprint on the observed neutrino events at Earth, emphasizing the most robust and least model-dependent signatures of mass ordering.

    ↳ hep-exastro-ph.HEhep-phnucl-exJ.Phys.G(2018)·81 citations
17. 17*

    Weinberg eigenvalues for chiral nucleon-nucleon interactions

    J. Hoppe🇩🇪 · C. Drischler🇩🇪 · R.J. Furnstahl🇺🇸 · K. Hebeler🇩🇪 · A. Schwenk🇩🇪

    We perform a comprehensive Weinberg eigenvalue analysis of a representative set of modern nucleon-nucleon interactions derived within chiral effective field theory. Our set contains local, semilocal, and nonlocal potentials, developed by Gezerlis, Tews et al. (2013); Epelbaum, Krebs, and Meißner (2015); and Entem, Machleidt, and Nosyk (2017) as well as Carlsson, Ekström et al. (2016), respectively. The attractive eigenvalues show a very similar behavior for all investigated interactions, whereas the magnitudes of the repulsive eigenvalues sensitively depend on the details of the regularization scheme of the short- and long-range parts of the interactions. We demonstrate that a direct comparison of numerical cutoff values of different interactions is in general misleading due to the different analytic form of regulators; for example, a cutoff value of $R=0.8$ fm for the semilocal interactions corresponds to about $R=1.2$ fm for the local interactions. Our detailed comparison of Weinberg eigenvalues provides various insights into idiosyncrasies of chiral potentials for different orders and partial waves. This shows that Weinberg eigenvalues could be used as a helpful monitoring scheme when constructing new interactions.

    ↳ nucl-thhep-phPRC(2017)·57 citations
18. 18*

    A Tale of Two Loops: Simplifying All-Plus Yang-Mills Amplitudes

    Gustav Mogull🇬🇧

    Pure Yang-Mills amplitudes with all external gluons carrying positive helicity, known as all-plus amplitudes, have an especially simple structure. The tree amplitudes vanish and, up to at least two loops, the loop-level amplitudes are related to those of $\mathcal{N}=4$ super-Yang-Mills (SYM) theory. This makes all-plus amplitudes a useful testing ground for new methods of simplifying more general classes of amplitudes. In this thesis we consider three new approaches, focusing on the structure before integration.

    ↳ hep-thhep-ph0 citations
19. 19*

    Highly Symmetric D-brane-Anti-D-brane Effective Actions

    Ehsan Hatefi🇦🇹

    The entire S-matrix elements of four, five and six point functions of D-brane-anti D-brane system are explored. To deal with symmetries of string amplitudes as well as their all order ${\alpha }^{\prime }$ corrections we first address a four point function of one closed string Ramond-Ramond (RR) and two real tachyons on the world volume of brane-anti brane system. We then focus on symmetries of string theory as well as universal tachyon expansion to achieve both string and effective field theory of an RR and three tachyons where the complete algebraic analysis for the whole S-matrix $<V_{C^{-1}}{V}_{T^{-1}}{V}_{T^0}{V}_{T^0}>$ was also revealed. Lastly, we employ all the conformal field theory techniques to $<V_{C^{-1}}{V}_{T^{-1}}{V}_{T^0}{V}_{T^0}{V}_{T^0}>$, working out with symmetries of theory and find out the expansion for the amplitude to be able to precisely discover all order singularity structures of D-brane-anti-D-brane effective actions of string theory. Various remarks about the so called generalized Veneziano amplitude and new string couplings are elaborated as well.

    ↳ hep-thgr-qchep-phJHEP(2017)·7 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.