Tue·Aug 28, 2018Tuesday·August 28, 2018

1. 01*

   Comment on "${\eta }_c$ production in photon-induced interactions at the LHC"

   Spencer R. Klein🇺🇸

   In "${\eta }_c$ production in photon-induced interactions at the LHC," \cite{Goncalves:2018yxc} Goncalves and Moreira discuss inclusive and exclusive ${\eta }_c$ production at $pp$ and $pA$ collisions at LHC energies. The exclusive channels are via two-photon and photon-Odderon interactions. This comment points out that there is a large additional source of almost-exclusive ${\eta }_c$ in ultra-peripheral collisions: from the radiative decay of $J/\psi$ that are produced in photon-nucleon interactions. Although the $J/\psi \to \gamma {\eta }_c$ branching ratio is small, the $J/\psi$ production cross-section is large enough that it dominates over the exclusive channels considered in \cite{Goncalves:2018yxc}, and is comparable to the non-exclusive production. In $J/\psi \to \gamma {\eta }_c$, the photon is very soft and therefore easy to miss, and the ${\eta }_c$ will have very similar kinematics to the $J/\psi$.

   hep-phPRD(2018)·17 citations
2. 02*

   The $K{\bar{K}}^{\ast }$ interaction in the unitary coupled-channel approximation

   Da-Ming Wan🇨🇳 · Si-Yu Zhao🇨🇳 · Bao-Xi Sun🇨🇳

   The $K{\bar{K}}^{\ast }$ interaction Lagrangian is constructed when the $SU(3)$ hidden gauge symmetry is taken into account, and then the $K{\bar{K}}^{\ast }$ potential is obtained. In the low energy region, the $K{\bar{K}}^{\ast }$ potential mainly comes from the contribution of the $t-$channel interaction by exchanging $\rho$,$\omega$ and $\phi$ mesons, respectively. The $K{\bar{K}}^{\ast }$ amplitude is investigated by solving the Bethe-Salpeter equation in the unitary coupled-channel approximation, where the loop function of the vector and pseudoscalar mesons are evaluated in the dimensional regularization scheme, and the contribution of the longitudinal part of the intermediate vector meson propagator is included in the calculation. Finally, it is found that a resonance state of $K{\bar{K}}^{\ast }$ is generated in the isospin $I=0$ sector, which might correspond to the $f_1(1420)$ particle in the review of the particle data group(PDG). Moreover, in the isospin $I=1$ sector, a pole of the $K{\bar{K}}^{\ast }$ amplitude is detected at $1425-i316$MeV on the complex plane of the total energy in the center of mass system, which is higher than the $K{\bar{K}}^{\ast }$ threshold. Thus this pole might be a resonance state of $K{\bar{K}}^{\ast }$ although no counterpart has been found in the PDG review.

   hep-ph3 citations
3. 03*

   Mass spectra of heavy mesons with instanton effects

   Qian Wu🇨🇳 · Emiko Hiyama🇯🇵 · Hyun-Chul Kim🇰🇷 · Ulugbek Yakhshiev🇰🇷 · Hongshi Zong🇨🇳

   We investigate the mass spectra of ordinary heavy mesons, based on a nonrelativistic potential approach. The heavy-light quark potential contains the Coulomb-type potential arising from one-gluon exchange, the confining potential, and the instanton-induced nonperturbative local heavy-light quark potential. All parameters are theoretically constrained and fixed. We carefully examine the effects from the instanton vacuum. Within the present form of the local potential from the instanton vacuum, we conclude that the instanton effects are rather marginal on the charmed mesons.

   hep-phhep-exPTEP(2018)·0 citations
4. 04*

   Lepton masses and mixing in a two-Higgs-doublet model

   Piotr Chaber🇵🇱 · Bartosz Dziewit🇵🇱 · Jacek Holeczek🇵🇱 · Monika Richter🇵🇱 · Marek Zrałek🇵🇱 · Sebastian Zając🇵🇱

   Within the framework of the two-Higgs Doublet Model (2HDM), we attempt to find some discrete, non-abelian flavour symmetry which could provide an explanation for the masses and mixing matrix elements of leptons. Unlike the Standard Model, currently there is no need for the flavour symmetry to be broken. With the GAP program we investigate all finite subgroups of the U3 group up to the order of 1025. Up to such an order there is no group for which it is possible to select free model parameters in order to match the masses of charged leptons, masses of neutrinos, and the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix elements in a satisfactory manner.

   hep-phPRD(2018)·18 citations
5. 05*

   NNLO PDFs for the LHC

   S. Alekhin🇩🇪 · J. Bluemlein🇩🇪 · S.-O. Moch🇩🇪

   We consider some trends, achievements and a series of remaining problems in the precision determination of parton distribution functions. For the description of the scaling violations of the deep-inelastic scattering data, forming the key ingredients to all PDF fits, a solid theoretical framework is of importance. It is provided by the fixed flavor number scheme in describing the heavy-quark contributions which is found in good agreement with the present experimental data in a very wide range of momentum transfers. In this framework also a consistent determination of the heavy-quark masses is possible at high precision. The emerging Drell-Yan data measured at hadron colliders start to play a crucial role in disentangling the quark species, particularly at small and large values of $x$. These new inputs demonstrate a good overall consistency with the earlier constraints on the PDFs coming from fixed-target experiments. No dramatic change is observed in the PDFs in case of a consistent account of the higher-order QCD corrections and when leaving enough flexibility in the PDF shape parameterization.}

   hep-phhep-exPoS(2018)·3 citations
6. 06*

   Analytical Soft SUSY Spectrum in Mirage-Type Mediation Scenarios

   Fei Wang🇨🇳

   We derive explicitly the soft SUSY breaking parameters at arbitrary low energy scale in the (deflected) mirage type mediation scenarios with possible gauge or Yukawa mediation contributions. Based on the Wilsonian effective action after integrating out the messengers, we obtain analytically the boundary value (at the GUT scale) dependencies of the effective wavefunctions and gauge kinetic terms. Note that the messenger scale dependencies of the effective wavefunctions and gauge kinetic terms had already been discussed in GMSB. The RGE boundary value dependencies, which is a special feature in (deflected) mirage type mediation, is the key new ingredients in this study. The appearance of ${}^{\prime }mirag{e}^{\prime }$ unification scale in mirage mediation is proved rigorously with our analytical results. We also discuss briefly the new features in deflected mirage mediation scenario in the case the deflection comes purely from the Kahler potential and the case with messenger-matter interactions.

   hep-phJHEP(2018)·6 citations
7. 07*

   Fermion spectral function in hot strongly interacting matter from the functional renormalization group

   Ziyue Wang🇨🇳 · Lianyi He🇨🇳

   We present the first calculation of fermion spectral function at finite temperature in quark-meson model in the framework of the functional renormalization group (FRG). We compare the results in two truncations, after first evolving flow equation of effective potential, we investigate the spectral function either by taking the IR values as input to calculate one-loop self-energy or by taking the scale-dependent values as input to evolve the flow equation of the fermion two-point function. The latter one is a self-consistent procedure in the framework of FRG. In both truncations, we find a multi-peak structure in the spectral function, indicating quark collective excitations realized in terms of the Landau damping. However, in contrast to fermion zero-mode in the one-loop truncation, we find a fermion soft-mode in the self-consistent truncation, which approaches the zero-mode as temperature increases.

   hep-phhep-thPRD(2018)·13 citations
8. 08*

   Odderon effects in the differential cross-sections at Tevatron and LHC energies

   Evgenij Martynov🇺🇦 · Basarab Nicolescu🇷🇴

   In the present paper, we extend the Froissaron-Maximal Odderon (FMO) approach at $t$ different from 0. Our extended FMO approach gives an excellent description of the 3266 experimental points considered in a wide range of energies and momentum transferred. We show that the very interesting TOTEM results for proton-proton differential cross-section in the range 2.76-13 TeV, together with the Tevatron data for antiproton-proton at 1.8 and 1.96 TeV give further experimental evidence for the existence of the Odderon. One spectacular theoretical result is the fact that the difference in the dip-bump region between $\bar{p}p$ and $pp$ differential cross-sections is diminishing with increasing energies and for very high energies (say 100 TeV), the difference between $\bar{p}p$ and $pp$ in the dip-bump region is changing its sign: $pp$ becomes bigger than $\bar{p}p$ at $|t|$ about 1 GeV${}^2$. This is a typical Odderon effect. Another important - phenomenological - result of our approach is that the slope in $pp$ scattering has different behavior in $t$ than the slope in $\bar{p}p$ scattering. This is also a clear Odderon effect.

   hep-phhep-exEPJC(2019)·59 citations
9. 09*

   The TauSpinner approach for electroweak corrections in LHC Z to ll observables

   E. Richter-Was🇵🇱 · Z. Was🇵🇱

   The LHC enters era of the Standard Model Z-boson couplings precise measurements, to match precision of LEP. The calculations of electroweak (EW) corrections in the Monte Carlo generators become of relevance. Precise predictions of Z-boson production and decay require classes of QED/EW/QCD corrections, preferably in the manner which allows for separation from the QCD dynamics of the production. At LEP, calculations, genuine weak and lineshape corrections were introduced into electroweak form-factors and Improved Born Approximation. This was well suited for so-called doubly-deconvoluted observables around the Z-pole; observables for which the initial- and final-state QED real and virtual emissions are treated separately or integrated over. This approach to EW corrections is followed for LHC pp collisions. We focus on the EW corrections to doubly-deconvoluted observables of Z to ll process, in a form of per-event weight and on numerical results. The reweighting technique of TauSpinner package is revisited and the program is enriched with the EW sector. The Dizet library, as interfaced to KKMC Monte Carlo of the LEP era, is used to calculate O(alpha) weak loop corrections, supplemented by some higher-order terms. They are used in the form of look-up tables by the TauSpinner package. The size of the corrections is evaluated for the following observables: the Z-boson resonance line-shape, the outgoing leptons forward-backward asymmetry, effective leptonic weak mixing angles and the lepton distribution spherical harmonic expansion coefficients. Evaluation of the EW corrections for observables with simplified calculations based on Effective Born of modified EW couplings, is also presented and compared with the predictions of Improved Born Approximation where complete set of EW form-factors is used.

   hep-phEPJC(2019)·10 citations
10. 10*

    xFitter 2.0.0: Heavy quark matching scales: Unifying the FFNS and VFNS

    The xFitter Developers' Team: V. Bertone🇳🇱 · D. Britzger🇩🇪 · S. Camarda🇨🇭 · A. Cooper-Sarkar🇬🇧 · A. Geiser🇩🇪 · F. Giuli🇬🇧 · A. Glazov🇩🇪 · E. Godat🇺🇸 · A. Kusina🇵🇱 · A. Luszczak🇵🇱 · F. Lyonnet🇺🇸 · F. Olness🇺🇸 and 4 other authors

    xFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton for many different kinds of analyses in Quantum Chromodynamics (QCD). It incorporates experimental data from a wide range of experiments including fixed-target, Tevatron, HERA, and LHC. xFitter version 2.0.0 has recently been released, and offers an expanded set of tools and options. The new xFitter 2.0.0 program links to the APFEL code which has implemented generalized matching conditions that enable the switch from $N_F$ to $N_F+1$ active flavors at an arbitrary matching scale ${\mu }_m$. This enables us to generalize the transition between a FFNS and a VFNS and essentially vary continuously between the two schemes; in this sense the matching scale ${\mu }_m$ allows us to unify the FFNS and VFNS in a common framework. This paper provides a brief overview of xFitter with emphasis of these new features.

    hep-phPoS(2018)·2 citations
11. 11*

    Symmetries and Mass Degeneracies in the Scalar Sector

    Howard E. Haber🇺🇸 · O.M. Ogreid🇳🇴 · P. Osland🇳🇴 · M.N. Rebelo🇵🇹

    We explore some aspects of models with two and three SU(2) scalar doublets that lead to mass degeneracies among some of the physical scalars. In Higgs sectors with two scalar doublets, the exact degeneracy of scalar masses, without an artificial fine-tuning of the scalar potential parameters, is possible only in the case of the inert doublet model (IDM), where the scalar potential respects a global U(1) symmetry that is not broken by the vacuum. In the case of three doublets, we introduce and analyze the replicated inert doublet model, which possesses two inert doublets of scalars. We then generalize this model to obtain a scalar potential, first proposed by Ivanov and Silva, with a CP4 symmetry that guarantees the existence of pairwise degenerate scalar states among two pairs of neutral scalars and two pairs of charged scalars. Here, CP4 is a generalized CP symmetry with the property that $(\mathrm{CP}4{)}^n$ is the identity operator only for integer $n$ values that are multiples of 4. The form of the CP4-symmetric scalar potential is simplest when expressed in the Higgs basis, where the neutral scalar field vacuum expectation value resides entirely in one of the scalar doublet fields. The symmetries of the model permit a term in the scalar potential with a complex coefficient that cannot be removed by any redefinition of the scalar fields within the class of Higgs bases (in which case, we say that no real Higgs basis exists). A striking feature of the CP4-symmetric model is that it preserves CP even in the absence of a real Higgs basis, as illustrated by the cancellation of the contributions to the CP violating form factors of the effective ZZZ and ZWW vertices.

    hep-phJHEP(2019)·32 citations
12. 12*

    On coupled-channel dynamics in the presence of anomalous thresholds

    M.F.M. Lutz🇩🇪 · C.L. Korpa🇭🇺

    We explore a general framework how to treat coupled-channel systems in the presence of overlapping left and right-hand cuts as well as anomalous thresholds. Such systems are studied in terms of a generalized potential, where we exploit the known analytic structure of t- and u-channel forces as the exchange masses get smaller approaching their physical values. Given an approximate generalized potential the coupled-channel reaction amplitudes are defined in terms of non-linear systems of integral equations. For large exchange masses, where there are no anomalous thresholds present, conventional $N/D$ methods are applicable to derive numerical solutions to the latter. At a formal level a generalization to the anomalous case is readily formulated by use of suitable contour integrations with amplitudes to be evaluated at complex energies. However, it is a considerable challenge to find numerical solutions to anomalous systems set up on a set of complex contours. By a suitable deformations of left-hand and right-hand cut lines we managed to establish a framework of linear integral equations defined for real energies. Explicit expressions are derived for the driving terms that hold for an arbitrary number of channels. Our approach is illustrated in terms of a schematic 3-channel systems. It is demonstrated that despite the presence of anomalous thresholds the scattering amplitude can be represented in terms of 3 phase shifts and 3 in-elasticity parameters, as one would expect from the coupled-channel unitarity condition.

    hep-phhep-latnucl-thPRD(2018)·10 citations
13. 13*

    Scale-Invariant Two Component Dark Matter

    Seyed Yaser Ayazi🇮🇷 · Ahmad Mohamadnejad🇮🇷

    We study a scale invariant extension of the standard model which can explain simultaneously dark matter and the hierarchy problem. In our set-up, we introduce a scalar and a spinor as two-component dark matter in addition to scalon field as a mediator. Interesting point about our model is that due to scale invariant conditions, compared to other two-component dark matter models, it has lower independent parameters. Possible astrophysical and laboratory signatures of two-component dark matter candidate are explored and it is shown that the most contribution of observed relic density of dark matter can be determined by spinor dark matter. Detectability of these dark matter particles is studied and the direct and invisible Higgs decay experiments are used to rule out part of the parameter space of the model. In addition, the dark matter self-interactions are considered and shown that their contribution saturate this constraint in the resonant regions.

    hep-phEPJC(2019)·47 citations
14. 14*

    Probing CP violating Higgs sectors via the precision measurement of coupling constants

    Mayumi Aoki🇯🇵 · Katsuya Hashino🇯🇵 · Daiki Kaneko🇯🇵 · Shinya Kanemura🇯🇵 · Mitsunori Kubota🇯🇵

    We study how effects of the CP violation can be observed indirectly by precision measurements of Higgs boson couplings at a future Higgs factory such as the international linear collider. We consider two Higgs doublet models with the softly broken discrete symmetry. We find that by measuring the Higgs boson couplings very precisely we are able to distinguish the two Higgs doublet model with CP violation from the CP conserving one.

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

    Exploring non minimal Universal Extra Dimensional Model at the LHC

    Nabanita Ganguly🇮🇳 · Anindya Datta🇮🇳

    We study the collider phenomenology of non minimal universal extra dimensional (nmUED) model in the context of the Large Hadron Collider at CERN. nmUED is an incarnation of the Standard Model in $(4+1)$ space-time dimensions compactified on an ${\mathbf{S}}_1/{\mathbf{Z}}_2$ orbifold supplemented with boundary localized operators with unknown coefficients. These coefficients parametrize the radiative corrections which are somehow arbitrary due to the lack of knowledge of the cut-off scale of such effective theory. It is possible to tune the masses and couplings of the Kaluza Klein (KK) excitations by tuning these parameters. Two scenarios with different mass hierarchies among the KK-excitations have been considered. A detailed study of production cross-sections and different decay modes of KK-particles are also presented. We calculate the correlated bounds on masses of KK-particles using the LHC $nl+mj+E{/}_T$ data (in case of production of strongly interacting particles) and $3l+E{/}_T$ data (in case of electroweak productions). We work in a KK-parity conserving scenario where the lightest KK-particle is a potential dark (DM) matter candidate. We use the additional constraints coming from the observed DM relic density of the universe to identify the allowed parameter space. The current status of a nmUED model in the light of DM direct detection data is also examined. The present investigation reveals that production and subsequent leptonic decays of KK-electroweak gauge bosons as massive as 1 TeV, lead to observable trilepton signature with a luminosity of 1 ab${}^{-1}$ which will be realized in near future.

    hep-phJHEP(2018)·11 citations
16. 16*

    Determination of $f_0-a_0^0$ mixing angle from QCD sum rules

    T.M.Aliev🇹🇷 · S.Bilmis🇹🇷

    By assuming that the $f_0$ and $a_0^0$ mesons are mixed states of the two-quark - tetraquark, the mixing angle between them is estimated within QCD sum rules method, and it is obtained that the mixing angle is $(6.03\pm 0.08{)}^{\circ }$. Our prediction on mixing angle can be checked in further experiments which can shed light on choosing the "right" structure of $f_0$ and $a_0^0$ mesons.

    hep-phEPJA(2018)·10 citations
17. 17*

    Monopole production via photon fusion and Drell-Yan processes: MADGRAPH implementation and perturbativity via velocity-dependent coupling and magnetic moment as novel features

    S. Baines🇬🇧 · N. E. Mavromatos🇬🇧 · V. A. Mitsou🇪🇸 · J. L. Pinfold🇨🇦 · A. Santra🇪🇸

    In this work we consider point-like monopole production via photon-fusion and Drell-Yan processes in the framework of an effective U(1) gauge field theory obtained from conventional models describing the interaction of spin 0, 1/2, 1 magnetically-charged fields with ordinary photons, upon electric-magnetic dualisation. We present arguments based on such dualities which support the conjecture of an effective monopole-velocity-dependent magnetic charge. For the cases of spin-1/2 and spin-1 monopoles, we also include a magnetic-moment term kappa, which is treated as a new phenomenological parameter and, together with the velocity-dependent coupling, allows for a perturbative treatment of the cross-section calculation. We discuss unitarity issues within these effective field theories, in particular we point out that in the spin-1 monopole case only the value kappa=1 may restore unitarity. However from an effective-field-theory point of view, this lack of unitarity should not be viewed as an impediment for the phenomenological studies and experimental searches of generic spin-1 monopoles, given that the potential appearance of new degrees of freedom in the ultraviolet completion of such models might restore it. The second part of the paper deals with an appropriate implementation of photon-fusion and Drell-Yan processes based on the above theoretical scenarios into MADGRAPH UFO models, aimed to serve as a useful tool in interpretations of monopole searches at colliders such as LHC, especially for photon fusion, given that it has not been considered by experimental collaborations so far. Moreover, the experimental implications of such perturbatively reliable monopole searches have been laid out.

    hep-phhep-exEPJC(2018)·70 citations
18. 18*

    Precision Photon Spectra for Wino Annihilation

    Matthew Baumgart🇺🇸 · Timothy Cohen🇺🇸 · Emmanuel Moulin🇫🇷 · Ian Moult🇺🇸 · Lucia Rinchiuso🇫🇷 · Nicholas L. Rodd🇺🇸 · Tracy R. Slatyer🇺🇸 · Iain W. Stewart🇺🇸 · Varun Vaidya🇺🇸

    We provide precise predictions for the hard photon spectrum resulting from neutral SU$(2{)}_W$ triplet (wino) dark matter annihilation. Our calculation is performed utilizing an effective field theory expansion around the endpoint region where the photon energy is near the wino mass. This has direct relevance to line searches at indirect detection experiments. We compute the spectrum at next-to-leading logarithmic (NLL) accuracy within the framework established by a factorization formula derived previously by our collaboration. This allows simultaneous resummation of large Sudakov logarithms (arising from a restricted final state) and Sommerfeld effects. Resummation at NLL accuracy shows good convergence of the perturbative series due to the smallness of the electroweak coupling constant - scale variation yields uncertainties on our NLL prediction at the level of $5\%$. We highlight a number of interesting field theory effects that appear at NLL associated with the presence of electroweak symmetry breaking, which should have more general applicability. We also study the importance of using the full spectrum as compared with a single endpoint bin approximation when computing experimental limits. Our calculation provides a state of the art prediction for the hard photon spectrum that can be easily generalized to other DM candidates, allowing for the robust interpretation of data collected by current and future indirect detection experiments.

    hep-phastro-ph.COastro-ph.HEJHEP(2019)·63 citations
19. 19*

    Quark-mass dependence in $\omega \to 3\pi$ decays

    Maximilian Dax🇩🇪 · Tobias Isken🇩🇪 · Bastian Kubis🇩🇪

    We study the quark-mass dependence of $\omega \to 3\pi$ decays, based on a dispersion-theoretical framework. We rely on the quark-mass-dependent scattering phase shift for the pion-pion $P$-wave extracted from unitarized chiral perturbation theory. The dispersive representation then takes into account the final-state rescattering among all three pions. The described formalism may be used as an extrapolation tool for lattice QCD calculations of three-pion decays, for which $\omega \to 3\pi$ can serve as a paradigm case.

    hep-phhep-latnucl-thEPJC(2018)·40 citations
20. 20*

    Probing the pre-BBN universe with gravitational waves from cosmic strings

    Yanou Cui🇺🇸 · Marek Lewicki🇬🇧 · David E. Morrissey🇨🇦 · James D. Wells🇺🇸

    Many motivated extensions of the Standard Model predict the existence of cosmic strings. Gravitational waves originating from the dynamics of the resulting cosmic string network have the ability to probe many otherwise inaccessible properties of the early universe. In this study we show how the spectrum of gravitational waves from a cosmic string network can be used to test the equation of state of the early universe prior to Big Bang Nucleosynthesis (BBN). We also demonstrate that current and planned gravitational wave detectors such as LIGO, LISA, DECIGO/BBO, and ET/CE have the potential to detect signals of a non-standard pre-BBN equation of state and evolution of the early universe (e.g., early non-standard matter domination or kination domination) or new degrees of freedom active in the early universe beyond the sensitivity of terrestrial collider experiments and cosmic microwave background measurements.

    hep-phastro-ph.COhep-thJHEP(2019)·208 citations
21. 21*

    Neutron Dark Matter Decays and Correlation Coefficients of Neutron Beta Decays

    A. N. Ivanov🇦🇹 · R. Höllwieser🇦🇹 · N. I. Troitskaya🇦🇹 · M. Wellenzohn🇦🇹 · Ya. A. Berdnikov🇷🇺

    As we have pointed out in (arXiv:1806.10107 [hep-ph]), the existence of neutron dark matter decay modes "n -> chi + anything", where "chi" is a dark matter fermion, for the solution of the neutron lifetime problem changes priorities and demands to describe the neutron lifetime "tau_n = 888.0(2.0)s", measured in beam experiments and defined by the decay modes "n -> p + anything", in the Standard Model (SM). The latter requires the axial coupling constant "lambda" to be equal to "lambda = - 1.2690" (arXiv:1806.10107 [hep-ph]). Since such an axial coupling constant is excluded by experimental data reported by the PERKEO II and UCNA Collaborations, the neutron lifetime "tau_n = 888.0(2.0)s" can be explained only by virtue of interactions beyond the SM, namely, by the Fierz interference term of order "b ~ - 10^{-2}" dependent on scalar and tensor coupling constants. We give a complete analysis of all correlation coefficients of the neutron beta decays with polarized neutron, taking into account the contributions of scalar and tensor interactions beyond the SM with the Fierz interference term "b ~ - 10^{-2}". We show that the obtained results agree well with the contemporary experimental data that does not prevent the neutron with the rate of the decay modes "n -> p + anything", measured in beam experiments, to have dark matter decay modes "n -> chi + anything".

    hep-phgr-qcnucl-exNPB(2019)·25 citations
22. 22*

    Does Compton/Schwarzschild duality in higher dimensions exclude TeV quantum gravity?

    Matthew J. Lake🇨🇳 · Bernard Carr🇬🇧

    In three spatial dimensions, the Compton wavelength $(R_C\propto M^{-1}$) and Schwarzschild radius $(R_S\propto M$) are dual under the transformation $M\to M_P^2/M$, where $M_P$ is the Planck mass. This suggests that there could be a fundamental link -- termed the Black Hole Uncertainty Principle or Compton-Schwarzschild correspondence -- between elementary particles with $M<M_P$ and black holes in the $M>M_P$ regime. In the presence of $n$ extra dimensions, compactified on some scale $R_E$ exceeding the Planck length $R_P$, one expects $R_S\propto M^{1/(1+n)}$ for $R_P<R<R_E$, which breaks this duality. However, it may be restored in some circumstances because the {\it effective} Compton wavelength of a particle depends on the form of the $(3+n)$-dimensional wavefunction. If this is spherically symmetric, then one still has $R_C\propto M^{-1}$, as in the $3$-dimensional case. The effective Planck length is then increased and the Planck mass reduced, allowing the possibility of TeV quantum gravity and black hole production at the LHC. However, if the wave function of a particle is asymmetric and has a scale $R_E$ in the extra dimensions, then $R_C\propto M^{-1/(1+n)}$, so that the duality between $R_C$ and $R_S$ is preserved. In this case, the effective Planck length is increased even more but the Planck mass is unchanged, so that TeV quantum gravity is precluded and black holes cannot be generated in collider experiments. Nevertheless, the extra dimensions could still have consequences for the detectability of black hole evaporations and the enhancement of pair-production at accelerators on scales below $R_E$. Though phenomenologically general for higher-dimensional theories, our results are shown to be consistent with string theory via the minimum positional uncertainty derived from $D$-particle scattering amplitudes.

    ↳ gr-qchep-phquant-phInt.J.Mod.Phys.D(2018)·15 citations
23. 23*

    Proton Mass Decomposition from the QCD Energy Momentum Tensor

    Yi-Bo Yang🇺🇸 · Jian Liang🇺🇸 · Yu-Jiang Bi🇨🇳 · Ying Chen🇨🇳 · Terrence Draper🇺🇸 · Keh-Fei Liu🇺🇸 · Zhaofeng Liu🇨🇳

    We report results on the proton mass decomposition and also on related quark and glue momentum fractions. The results are based on overlap valence fermions on four ensembles of $N_f=2+1$ DWF configurations with three lattice spacings and three volumes, and several pion masses including the physical pion mass. With fully non-perturbative renormalization (and universal normalization on both quark and gluon), we find that the quark energy and glue field energy contribute 33(4)(4)\% and 37(5)(4)\% respectively in the $\overline{MS}$ scheme at $\mu =2$ GeV. A quarter of the trace anomaly gives a 23(1)(1)\% contribution to the proton mass based on the sum rule, given 9(2)(1)\% contribution from the $u,d,$ and $s$ quark scalar condensates. The $u,d,s$ and glue momentum fractions in the $\overline{MS}$ scheme are in good agreement with global analyses at $\mu =2$ GeV.

    ↳ hep-lathep-phnucl-thPRL(2018)·224 citations
24. 24*

    Quarkonium in-medium properties from realistic lattice NRQCD

    Seyong Kim🇰🇷 · Peter Petreczky🇺🇸 · Alexander Rothkopf🇳🇴

    We present the final results of our high statistics study on the properties of bottomonium and charmonium at finite temperature. We focus on the temperature range around the crossover transition $150\le T\le 410$MeV, relevant for current heavy ion collision experiments. The QCD medium degrees of freedom which consist of dynamical u,d, and s quarks and gluons are captured by realistic state-of-the art ($m_{\pi }\approx 161$MeV) lattice QCD simulations of the HotQCD collaboration. For the heavy quarks we deploy the non-relativistic effective field theory of QCD, NRQCD. The in-medium properties of quarkonium are deduced from their spectral functions, which are reconstructed using improved and novel Bayesian approaches. Through a systematic analysis we shed light on the origin of the discrepancies in melting temperatures previously reported in the literature, showing that they are owed to underestimated methods uncertainties of the deployed spectral reconstructions. Our simulations corroborate a picture of sequential in-medium modification, ordered according to the vacuum binding energy of the states. As a central quantitative result, our study reveals how the mass of the heavy quarkonium ground state reduces as temperature increases. The observed spectral modifications are interpreted in the light of, and compared to previous studies based on the complex lattice potential for heavy quarkonium. Thus for the first time we provide a robust picture of in-medium heavy quarkonium modification in the quark-gluon plasma consistent among different non-relativistic methods. We also critically discuss the perspectives for improving on these results.

    ↳ hep-lathep-phJHEP(2018)·77 citations
25. 25*

    A status report on the phenomenology of black holes in loop quantum gravity: Evaporation, tunneling to white holes, dark matter and gravitational waves

    Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷 · Flora Moulin🇫🇷

    The understanding of black holes in loop quantum gravity is becoming increasingly accurate. This review focuses on the possible experimental or observational consequences of the underlying spinfoam structure of space-time. It adresses both the aspects associated with the Hawking evaporation and the ones due to the possible existence of a bounce. Finally, consequences for dark matter and gravitational waves are considered.

    ↳ gr-qcastro-ph.COhep-phUniverse(2018)·48 citations
26. 26*

    Where do the AMS-02 anti-helium events come from?

    Vivian Poulin🇺🇸 · Pierre Salati🇫🇷 · Ilias Cholis🇺🇸 · Marc Kamionkowski🇺🇸 · Joseph Silk🇫🇷

    We discuss the origin of the anti-helium-3 and -4 events possibly detected by AMS-02. Using up-to-date semi-analytical tools, we show that spallation from primary hydrogen and helium nuclei onto the ISM predicts a $\overline{{}^3\mathrm{He}}$ flux typically one to two orders of magnitude below the sensitivity of AMS-02 after 5 years, and a $\overline{{}^4\mathrm{He}}$ flux roughly 5 orders of magnitude below the AMS-02 sensitivity. We argue that dark matter annihilations face similar difficulties in explaining this event. We then entertain the possibility that these events originate from anti-matter-dominated regions in the form of anti-clouds or anti-stars. In the case of anti-clouds, we show how the isotopic ratio of anti-helium nuclei might suggest that BBN has happened in an inhomogeneous manner, resulting in anti-regions with a anti-baryon-to-photon ratio $\bar{\eta }\simeq 10^{-3}\eta$. We discuss properties of these regions, as well as relevant constraints on the presence of anti-clouds in our Galaxy. We present constraints from the survival of anti-clouds in the Milky-Way and in the early Universe, as well as from CMB, gamma-ray and cosmic-ray observations. In particular, these require the anti-clouds to be almost free of normal matter. We also discuss an alternative where anti-domains are dominated by surviving anti-stars. We suggest that part of the unindentified sources in the 3FGL catalog can originate from anti-clouds or anti-stars. AMS-02 and GAPS data could further probe this scenario.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2019)·109 citations
27. 27*

    Black holes in an Effective Field Theory extension of GR

    Vitor Cardoso🇵🇹 · Masashi Kimura🇵🇹 · Andrea Maselli🇵🇹 · Leonardo Senatore🇺🇸

    Effective field theory methods suggest that some rather-general extensions of General Relativity include, or are mimicked by, certain higher-order curvature corrections, with coupling constants expected to be small but otherwise arbitrary. Thus, the tantalizing prospect to test the fundamental nature of gravity with gravitational-wave observations, in a systematic way, emerges naturally. Here, we build black hole solutions in such a framework and study their main properties. Once rotation is included, we find the first purely gravitational example of geometries without ${\mathbb{Z}}_2$-symmetry. Despite the higher-order operators of the theory, we show that linearized fluctuations of such geometries obey second-order differential equations. We find nonzero tidal Love numbers. We study and compute the quasinormal modes of such geometries. These results are of interest to gravitational-wave science but also potentially relevant for electromagnetic observations of the galactic center or $X$-ray binaries.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRL(2018)·235 citations
28. 28*

    De Sitter vs Quintessence in String Theory

    Michele Cicoli🇮🇹 · Senarath de Alwis🇺🇸 · Anshuman Maharana🇮🇳 · Francesco Muia🇮🇹 · Fernando Quevedo🇮🇹

    De Sitter solutions have been recently conjectured to be incompatible with quantum gravity. In this paper we critically assess the progress and challenges of different mechanisms to obtain de Sitter vacua in string compactifications and compare them to quintessence models. We argue that, despite recent criticisms, de Sitter models reached a level of concreteness and calculational control which has been improving over time. On the other hand, building string models of quintessence appears to be more challenging and requires additional fine-tuning. We discuss the tension between the swampland conjecture and the Higgs potential and find examples which can evade fifth-force bounds even if they seem very hard to realise in string theory. We also comment on the tension with low-redshift data and explore ultra-light axions from string theory as dark energy candidates.

    ↳ hep-thastro-ph.COgr-qchep-phFortsch.Phys.(2019)·238 citations
29. 29*

    Form factor ratios for $B_s\to K\ell \nu$ and $B_s\to D_s\ell \nu$ semileptonic decays and $|V_{ub}/V_{cb}|$

    Christopher J. Monahan🇺🇸 · Chris M. Bouchard🇬🇧 · G. Peter Lepage🇺🇸 · Heechang Na🇺🇸 · Junko Shigemitsu🇺🇸

    We present a lattice quantum chromodynamics determination of the ratio of the scalar and vector form factors for two semileptonic decays of the $B_s$ meson: $B_s\to K\ell \nu$ and $B_s\to D_s\ell \nu$. In conjunction with future experimental data, our results for these correlated form factors will provide a new method to extract $|V_{ub}/V_{cb}|$, which may elucidate the current tension between exclusive and inclusive determinations of these Cabibbo-Kobayashi-Maskawa mixing matrix parameters. In addition to the form factor results, we determine the ratio of the differential decay rates, and forward-backward and polarization asymmetries, for the two decays.

    ↳ hep-lathep-phPRD(2018)·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.