Thu·Dec 5, 2019Thursday·December 5, 2019

1. 01*

   Fate of Heavy Quark Bound States inside Quark-Gluon Plasma

   Xiaojun Yao🇺🇸 · Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen Bass🇺🇸 · Thomas Mehen🇺🇸 · Berndt Müller🇺🇸

   Transport equations have been applied successfully to describe the quarkonium evolution inside the quark-gluon plasma, which include both plasma screening effects and recombination. We demonstrate how the quarkonium transport equation is derived from QCD by using the open quantum system framework and effective field theory. Weak coupling and Markovian approximations used in the derivation are justified from a separation of scales. By solving the equations numerically, we study the Upsilon production in heavy ion collisions.

   hep-phnucl-thHadron Spectroscopy and Structure, World …·3 citations
2. 02*

   NNLO real corrections to $gg\to HH$ in the large-$m_t$ limit

   Joshua Davies🇩🇪 · Florian Herren🇩🇪 · Go Mishima🇩🇪 · Matthias Steinhauser🇩🇪

   In this contribution we consider NNLO real radiation corrections to the total cross section for Higgs boson pair production in gluon fusion. Special emphasis is put on the cross check of the asymptotic expansion in the inverse top quark mass.

   hep-phPoS(2019)·10 citations
3. 03*

   Mirage mediation from the landscape

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Dibyashree Sengupta🇺🇸

   Rather general considerations from the string theory landscape suggest a statistical preference within the multiverse for soft SUSY breaking terms as large as possible subject to a pocket universe value for the weak scale not greater than a factor of 2-5 from our measured value. Within the gravity/moduli-mediated SUSY breaking framework, the Higgs mass is pulled to m_h~ 125 GeV while first/second generation scalars are pulled to tens of TeV scale and gauginos and third generation scalars remain at the few TeV range. In this case, one then expects comparable moduli- and anomaly-mediated contributions to soft terms, leading to mirage mediation. For an assumed stringy natural value of the SUSY mu parameter, we evaluate predicted sparticle mass spectra for mirage mediation from a statistical scan of the string landscape. We then expect a compressed spectrum of gauginos along with a higgsino-like LSP. For a linear (quadratic) statistical draw with gravitino mass m_{3/2}~ 20 TeV, then the most probable mirage scale is predicted to be around \mu_{mir}~10^{13} (10^{14}) GeV. SUSY should appear at high-luminosity LHC via higgsino pair production into soft dilepton pairs. Distinguishing mirage mediation from models with unified gaugino masses may have to await construction of an ILC with \sqrt{s}>2m(higgsino).

   hep-phPRResearch(2020)·16 citations
4. 04*

   Sensitivity for four-body tau-lepton decays at Belle and Belle II experiments

   I. Domínguez🇲🇽 · P. S. Mares Damas🇲🇽 · P. L. M. Podesta Lerma🇲🇽 · D. Rodríguez Pérez🇲🇽

   We study the expected sensitivity at Belle and Belle II for four-body ${\tau }^{\mp }\to X^{\pm }{l}^{\mp }{l}^{\mp }{\nu }_{\tau }$ decays where $l=e$ or $\mu$ and $X=\pi$, $K$, $\rho$ and $K^{\ast }$ mesons. These decay processes violate the total lepton number ($|\Delta L|=2$ ) and they can be induced by the exchange of Majorana neutrinos. In particular, we consider lifetimes in the accessible ranges of ${\tau }_N$ = 5, 100 ps and extract the limits on $|V_{\ell N}{|}^2$ without any additional assumption on the relative size of the mixing matrix elements. For an integrated luminosity collected of 1 ab${}^{-1}$ at Belle, we found significant sensitivity on branching fractions of the order BR(${\tau }^{\mp }\to X^{\pm }{l}^{\mp }{l}^{\mp }{\nu }_{\tau }$) $\sim 10^{-8}$. For an integrated luminosity expected of 50 ab${}^{-1}$ and intermediate luminosity of 10 ab${}^{-1}$ at the Belle II, we found significant sensitivity on branching fractions of the order BR(${\tau }^{\mp }\to X^{\pm }{l}^{\mp }{l}^{\mp }{\nu }_{\tau }$) $\sim 10^{-9}-10^{-8}$. We use these sensitivities to set limits for the exclusion regions on the parameter space $(m_N,|V_{\ell N}{|}^2)$ associated with the heavy neutrino; such that for a $|V_{\ell N}{|}^2\sim \mathcal{O}(10^{-5})$ at ${\tau }_N=100$ ps, we find the bounds as $0.140<m_N<1.776$ GeV for ${\tau }^{-}\to X^{+}{e}^{-}{e}^{-}{\nu }_{\tau }$ and $0.245<m_N<1.671$ GeV for ${\tau }^{-}\to X^{+}{\mu }^{-}{\mu }^{-}{\nu }_{\tau }$.

   hep-phphysics.acc-ph0 citations
5. 05*

   Automated Predictions from Polarized Matrix Elements

   Diogo Buarque Franzosi🇸🇪 · Olivier Mattelaer🇧🇪 · Richard Ruiz🇧🇪 · Sujay Shil🇮🇳

   The anticipated experimental resolution and data cache of the High Luminosity Large Hadron Collider will enable precision investigations of polarization in multiboson processes. This includes, for the first time, vector boson scattering. To facilitate such studies, we report the automation of polarized matrix element computations in the publicly available Monte Carlo tool suite, MadGraph5_aMC@NLO. This enables scattering and decay simulations involving helicity-polarized asymptotic or intermediate states, preserving both spin-correlation and off-shell effects. As demonstrations of the method, we investigate the leading order production and decay of polarized weak gauge bosons in the process $pp\to jj{W}_{\lambda }^{+}{W}_{{\lambda }^{\prime }}^{-}$, with helicity eigenstates $(\lambda ,{\lambda }^{\prime })$ defined in various reference frames. We consider the Standard Model at both $\mathcal{O}({\alpha }^4)$ and $\mathcal{O}({\alpha }^2{\alpha }_s^2)$ as well as a benchmark composite Higgs scenario. We report good agreement with polarization studies based on the On-Shell Projection (OSP) technique. Future capabilities are discussed.

   hep-phhep-exJHEP(2020)·86 citations
6. 06*

   Generalized Blind Spots for Dark Matter Direct Detection in the 2HDM

   M. E. Cabrera🇬🇹 · J. A. Casas🇪🇸 · A. Delgado🇺🇸 · S. Robles🇦🇺

   In this paper we study the presence of generalized blind spots, i.e. regions of the parameter space where the spin-independent cross section for dark matter direct detection is suppressed, in the context of a generic 2HDM and a minimal fermionic Higgs-portal dark sector. To this end, we derive analytical expressions for the couplings of the dark matter to the light and heavy Higgses, and thus for the blind spot solutions. Unlike the case of a standard Higgs sector, blind spots can occur even without a cancellation between different contributions, while keeping unsuppressed and efficient the annihilation processes in the early Universe involving Higgs states. As a consequence, the allowed parameter space is dramatically enhanced.

   hep-phastro-ph.COJHEP(2020)·14 citations
7. 07*

   $Z_H\to H^0\gamma$ decay within the littlest Higgs model at $\mathcal{O}({\alpha }_{\mathrm{ew}}^3{\alpha }_s)$ accuracy

   Ming-Ming Long🇨🇳 · Shao-Ming Wang🇨🇳 · Qiang Yang🇨🇳 · Ren-You Zhang🇨🇳 · Wen-Gan Ma🇨🇳 · Jian-Wen Zhu🇨🇳

   We study the rare decay $Z_H\to H^0\gamma$ at $\mathcal{O}({\alpha }_{\mathrm{ew}}^3{\alpha }_s)$ accuracy including two-loop QCD corrections in the context of the littlest Higgs model (LHM) without $T$-parity. We revisit analytically and numerically the leading-order (LO) contributions of the one-loop diagrams induced by massive fermions, scalars and charged gauge bosons in the LHM, and further study the NLO QCD correction to this decay process. We perform the numerical calculation by taking the LHM input parameters $f=3,4\text{TeV}$ and $0.1<c<0.6$, and discuss the numerical results of the decay width up to the QCD NLO within the recent experimentally constrained LHM parameter space region. Our results show that the two-loop QCD correction always reduces the LO decay width and the top-induced QCD correction is the dominant contribution at the QCD NLO. For $f=4\text{TeV}$ and $c=0.3$, the NLO QCD corrected decay width reaches $75.099\text{keV}$ and the NLO QCD relative correction is about $-11.0\%$.

   hep-phJ.Phys.G(2020)·1 citation
8. 08*

   Quantum Numbers of the Pentaquark States $P_c^{+}$ via Symmetry Analysis

   Chong-yao Chen🇨🇳 · Muyang Chen🇨🇳 · Yu-xin Liu🇨🇳

   We investigate the quantum numbers of the pentaquark states ${\text{P}}_{\text{c}}^{+}$, which are composed of four (three flavors) quarks and an antiquark, by analyzing their inherent nodal structure in this paper. Assuming that the four quarks form a tetrahedron or a square, and the antiquark locates at the center of the four quark cluster, we determine the nodeless structure of the states with orbital angular moment $L\le 3$, and in turn, the accessible low-lying states. Since the inherent nodal structure depends only on the inherent geometric symmetry, we propose the quantum numbers $J^P$ of the low-lying pentaquark states ${\text{P}}_c^{+}$ may be ${\frac{3}{2}}^{-}$, ${\frac{5}{2}}^{-}$, ${\frac{3}{2}}^{+}$, ${\frac{5}{2}}^{+}$, independent of dynamical models.

   hep-phCommun.Theor.Phys.(2020)·3 citations
9. 09*

   Probing stops in the coannihilation region at the HL-LHC: a comparative study of different processes

   Guang Hua Duan🇨🇳 · Xiang Fan🇨🇳 · Ken-ichi Hikasa🇯🇵 · Bo Peng🇨🇳 · Jin Min Yang🇨🇳

   In the minimal supersymmetric model, the coannihilation of the lighter stop ${\tilde{t}}_1$ and bino-like dark matter $\chi$ provides a feasible way to accommodate the correct dark matter relic abundance. In this scenario, due to the compressed masses, ${\tilde{t}}_1$ merely appears as missing energy at the LHC and thus the pair production of ${\tilde{t}}_1$ can only be probed by requiring an associated energetic jet. Meanwhile, since ${\tilde{t}}_2$ and ${\tilde{b}}_1$ are correlated in mass and mixing with ${\tilde{t}}_1$, the production of ${\tilde{t}}_2{\tilde{t}}_2^{\ast }$ or ${\tilde{b}}_1{\tilde{b}}_1^{\ast }$, each of which dominantly decays into ${\tilde{t}}_1$ plus $Z$, $h$ or $W$ boson, may serve as a complementary probe. We examine all these processes at the HL-LHC and find that the $2\sigma$ sensitivity to $\chi$ mass can be as large as about 570 GeV, 600 GeV and 1.1 TeV from the production process of ${\tilde{t}}_1{\tilde{t}}_1^{\ast }+\mathrm{jet}$, ${\tilde{t}}_2{\tilde{t}}_2^{\ast }$ and ${\tilde{b}}_1{\tilde{b}}_1^{\ast }$, respectively.

   hep-phPLB(2020)·3 citations
10. 10*

    PROPHECY4F 3.0: A Monte Carlo program for Higgs-boson decays into four-fermion final states in and beyond the Standard Model

    Ansgar Denner🇩🇪 · Stefan Dittmaier🇩🇪 · Alexander Mück🇩🇪

    The Monte Carlo generator PPROPHECY4F provides a PROPer description of the Higgs dECaY into 4 Fermions within the Standard Model, the Standard Model with a fourth fermion generation, a simple Higgs-singlet extension of the Standard Model, and the Two-Higgs-Doublet Model. The fully differential predictions include the full QCD and electroweak next-to-leading-order corrections, all interference contributions between different WW/ZZ channels, and all off-shell effects of intermediate W/Z bosons. PPROPHECY4F computes the inclusive partial decay widths and allows for the computation of binned differential distributions of the decay products. For leptonic final states also unweighted events are provided.

    hep-phComput.Phys.Commun.(2020)·43 citations
11. 11*

    Precise yield of high-energy photons from Higgsino dark matter annihilation

    Martin Beneke🇩🇪 · Caspar Hasner🇩🇪 · Kai Urban🇩🇪 · Martin Vollmann🇩🇪

    The impact of electroweak Sudakov logarithms on the endpoint of the photon spectrum for wino dark matter annihilation was studied intensively over the last several years. In this work, we extend these results to Higgsino dark matter ${\chi }_1^0$. We achieve NLL' resummation accuracy for narrow and intermediate spectral energy resolutions, of order $m_W^2/m_{\chi }$ and $m_W$, respectively. This is the most accurate prediction to date for the yield of high-energy $\gamma$-rays from ${\chi }_1^0{\chi }_1^0\to \gamma +X$ annihilation for the energy resolutions realized by current and next-generation telescopes. We also discuss for the first time the effect of power corrections in $m_W/m_{\chi }$ in this context and argue why they are not sizeable.

    hep-phastro-ph.HEJHEP(2020)·38 citations
12. 12*

    Predictions for $B_s\to {\bar{K}}^{\ast }\ell \ell$ in non-universal $Z^{\prime }$ models

    Ashutosh Kumar Alok🇮🇳 · Amol Dighe🇮🇳 · Shireen Gangal🇮🇳 · Dinesh Kumar🇵🇱

    The lepton flavor universality violating (LFUV) measurements $R_K$ and $R_{K^{\ast }}$ in $B$ meson decays can be accounted for in non-universal $Z^{\prime }$ models. We constrain the couplings of these $Z^{\prime }$ models by performing a global fit to correlated $b\to s\ell \ell$ and $b\to d\ell \ell$ processes, and calculate their possible implications for $B_s\to {\bar{K}}^{\ast }\ell \ell$ observables. For real new physics (NP) couplings, the 1-$\sigma$ favored parameters allow the corresponding LFUV ratio $R_{K^{\ast }}^{(s)}$ in $B_s\to {\bar{K}}^{\ast }\ell \ell$ to range between 0.8 -- 1.2 at low $q^2$. Complex NP couplings improve the best fit only marginally, however they allow a significant enhancement of the branching ratio, while increasing the range of $R_{K^{\ast }}^{(s)}$ at low $q^2$ to 0.8 -- 1.8. We find that NP could cause zero-crossing in the forward-backward asymmetry $A_{FB}$ to shift towards lower $q^2$ values, and enhancement in the magnitude of integrated $A_{FB}$. The $CP$ asymmetry $A_{CP}$ may be suppressed and even change sign. The simultaneous measurements of integrated $R_{K^{\ast }}^{(s)}$ and $A_{CP}$ values to 0.1 and 1% respectively, would help in constraining the effective NP Wilson coefficient $C_9$ in $b\to d\mu \mu$ interactions.

    hep-phhep-exEPJC(2020)·12 citations
13. 13*

    New physics searches with top quarks

    Susanne Westhoff🇩🇪

    This is a brief pedagogic introduction to searches for new physics with top quarks. It covers indirect searches for heavy new particles based on standard model effective theory and direct searches for new signatures of a light hidden sector. LHC and flavor observables complement and strengthen each other in this endeavor.

    hep-phhep-exPoS(2019)·2 citations
14. 14*

    Improved Bhabha cross section at LEP and the number of light neutrino species

    Patrick Janot🇨🇭 · Stanisław Jadach🇵🇱

    In ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions, the integrated luminosity is generally measured from the rate of low-angle Bhabha interactions ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\mathrm{e}}^{+}{\mathrm{e}}^{-}$. In the published LEP results, the inferred theoretical uncertainty of $\pm 0.061\%$ on the predicted rate is significantly larger than the reported experimental uncertainties. We present an updated and more accurate prediction of the Bhabha cross section in this letter, which is found to reduce the Bhabha cross section by about $0.048\%$, and its uncertainty to $\pm 0.037\%$. When accounted for, these changes modify the number of light neutrino species (and its accuracy), as determined from the LEP measurement of the hadronic cross section at the Z peak, to $N_{\nu }=2.9963\pm 0.0074$. The 20-years-old $2\sigma$ tension with the Standard Model is gone.

    hep-phhep-exPLB(2020)·141 citations
15. 15*

    NLO QCD Corrections to Inclusive Charmonium and $B_c$ Meson Production in $W^{+}$ Decays

    Zi-Qiang Chen🇨🇳 · Hao Yang🇨🇳 · Cong-Feng Qiao🇨🇳

    We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to inclusive processes $W^{+}\to J/\psi ({\eta }_c)+c+\bar{s}+X$ and $W^{+}\to B_c(B_c^{\ast })+b+\bar{s}+X$ in the framework of nonrelativistic QCD (NRQCD) factorization formalism. Result indicates that the NLO corrections are significant, and the uncertainties in theoretical predictions with NLO corrections are greatly reduced. The charmonium and $B_c$ meson yielding rates at the Large Hadron Collider (LHC) are given.

    hep-phPRD(2020)·2 citations
16. 16*

    Multiple charm and hidden charm mesons with strangeness

    Xiu-Lei Ren🇩🇪 · Brenda B. Malabarba🇧🇷 · L. S. Geng🇨🇳 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷

    In this talk we summarize our latest results on the study of three-body systems with explicit/hidden charm and with strangeness. In particular, we focus on the $KDD$ and $KD{\bar{D}}^{\ast }$ systems, where a charm $+2$, isospin $1/2$ and strangeness $+1$ state is found with a mass around 4140 MeV in the former and a $K^{\ast }$ state, with hidden charm, at a mass around 4307 MeV is obtained in the latter. Both states are predictions of our model and the experimental confirmation of them would be important to understand the properties of the strong interaction in the presence of heavy quarks.

    hep-phnucl-th0 citations
17. 17*

    Subleading Power Resummation of Rapidity Logarithms: The Energy-Energy Correlator in $\mathcal{N}=4$ SYM

    Ian Moult🇺🇸 · Gherardo Vita🇺🇸 · Kai Yan🇩🇪

    We derive and solve renormalization group equations that allow for the resummation of subleading power rapidity logarithms. Our equations involve operator mixing into a new class of operators, which we term the "rapidity identity operators", that will generically appear at subleading power in problems involving both rapidity and virtuality scales. To illustrate our formalism, we analytically solve these equations to resum the power suppressed logarithms appearing in the back-to-back (double light cone) limit of the Energy-Energy Correlator (EEC) in $\mathcal{N}$=4 super-Yang-Mills. These logarithms can also be extracted to $\mathcal{O}({\alpha }_s^3)$ from a recent perturbative calculation, and we find perfect agreement to this order. Instead of the standard Sudakov exponential, our resummed result for the subleading power logarithms is expressed in terms of Dawson's integral, with an argument related to the cusp anomalous dimension. We call this functional form "Dawson's Sudakov". Our formalism is widely applicable for the resummation of subleading power rapidity logarithms in other more phenomenologically relevant observables, such as the EEC in QCD, the $p_T$ spectrum for color singlet boson production at hadron colliders, and the resummation of power suppressed logarithms in the Regge limit.

    hep-phhep-thJHEP(2020)·82 citations
18. 18*

    UV Sensitivity of the Axion Mass from Instantons in Partially Broken Gauge Groups

    Csaba Csaki🇺🇸 · Maximilian Ruhdorfer🇩🇪 · Yuri Shirman🇺🇸

    We examine the contribution of small instantons to the axion mass in various UV completions of QCD. We show that the reason behind the potential dominance of such contributions is the non-trivial embedding of QCD into the UV theory. The effects from instantons in the partially broken gauge group appear as "fractional instanton" corrections in the effective theory. These will exhibit unusual dependences on the various scales in the problem whenever the index of embedding is non-trivial. We present a full one-instanton calculation of the axion mass in the simplest product group models, carefully keeping track of numerical prefactors. Rather than using a 't Hooft operator approximation we directly evaluate the contributions to the vacuum bubble, automatically capturing the effects of closing up external fermion lines with Higgs loops. This approach is manifestly finite and removes the uncertainty associated with introducing a cutoff scale for the Higgs loops. We verify that the small instantons may dominate over the QCD contribution for very high breaking scales and at least three group factors.

    hep-phhep-thJHEP(2020)·86 citations
19. 19*

    Large Higgs quartic coupling and (A)DM from extended Bosonic Technicolor

    Mads T. Frandsen🇩🇰 · Wei-Chih Huang🇩🇰

    We propose novel bosonic Technicolor models augmented by an $SU(2{)}_R$ gauge group and scalar doublet. Dynamical breaking of $SU(2{)}_R$ induced by technifermion condensation triggers $SU(2{)}_L$ breaking via a portal coupling. The scale of the new strong interactions is as high as that of composite Higgs models, and the vacuum stability challenge confronting ordinary bosonic Technicolor models is avoided. Thermal or asymmetric dark matter, whose stability is ensured by a $U(1{)}_{\mathrm{TB}}$ technibaryon symmetry, can be realized. In the latter case, the correct relic density can be reproduced for a wide range of dark matter mass via leptogenesis.

    hep-phhep-thPLB(2021)·2 citations
20. 20*

    Multi-Higgs Boson Probes of the Dark Sector

    Marvin Flores🇿🇦 · Christian Gross🇮🇹 · Jong Soo Kim🇿🇦 · Oleg Lebedev🇫🇮 · Subhadeep Mondal🇫🇮

    We consider dark sectors with spontaneously broken gauge symmetries, where cascade decays of the dark sector fields naturally produce multi-Higgs boson final states along with dark matter. Our study focuses on two and three Higgs boson final states with missing energy using a multivariate analysis with Boosted Decision Trees. We find that the di-Higgs boson channel is quite promising for the $\bar{b}b+\gamma \gamma$ and $\bar{b}b+\bar{\ell }\ell$ decay modes. The tri-Higgs boson final state with missing energy, on the other hand, appears to be beyond the reach of the LHC in analogous channels. This may change when fully hadronic Higgs boson decays are considered.

    hep-phPRD(2020)·6 citations
21. 21*

    Beyond the Standard Models with Cosmic Strings

    Yann Gouttenoire🇩🇪 · Géraldine Servant🇩🇪 · Peera Simakachorn🇩🇪

    We examine which information on the early cosmological history can be extracted from the potential measurement by third-generation gravitational-wave observatories of a stochastic gravitational wave background (SGWB) produced by cosmic strings. We consider a variety of cosmological scenarios breaking the scale-invariant properties of the spectrum, such as early long matter or kination eras, short intermediate matter and inflation periods inside a radiation era, and their specific signatures on the SGWB. This requires to go beyond the usually-assumed scaling regime, to take into account the transient effects during the change of equation of state of the universe. We compute the time evolution of the string network parameters and thus the loop-production efficiency during the transient regime, and derive the corresponding shift in the turning-point frequency. We consider the impact of particle production on the gravitational-wave emission by loops. We estimate the reach of future interferometers LISA, BBO, DECIGO, ET and CE and radio telescope SKA to probe the new physics energy scale at which the universe has experienced changes in its expansion history. We find that a given interferometer may be sensitive to very different energy scales, depending on the nature and duration of the non-standard era, and the value of the string tension. It is fascinating that by exploiting the data from different GW observatories associated with distinct frequency bands, we may be able to reconstruct the full spectrum and therefore extract the values of fundamental physics parameters.

    hep-phastro-ph.COJCAP(2020)·218 citations
22. 22*

    Electromagnetic and gravitomagnetic structure of pions and pion-nucleon scattering

    O.V. Selyugin🇷🇺

    Taking into account PDFs obtained by various Collaborations, the momentum transfer dependence of GPDs of the pion are obtained. The calculated electromagnetic and gravitomagnetic form factors of the pions and nucleons are used for the description of the pion-nucleon elastic scattering in a wide energy and momentum transfer region with minimum fitting parameters.

    hep-phhep-exJ.Phys.Conf.Ser.(2020)·0 citations
23. 23*

    Gravity-mediated Dark Matter in Clockwork/Linear Dilaton Extra-Dimensions

    Miguel G. Folgado🇪🇸 · Andrea Donini🇪🇸 · Nuria Rius🇪🇸

    We study for the first time the possibility that Dark Matter (represented by particles with spin $0,1/2$ or $1$) interacts gravitationally with Standard Model particles in an extra-dimensional Clockwork/Linear Dilaton model. We assume that both, the Dark Matter and the Standard Model, are localized in the IR-brane and only interact via gravitational mediators, namely the Kaluza-Klein (KK) graviton and the radion/KK-dilaton modes. We analyse in detail the Dark Matter annihilation channel into Standard Model particles and into two on-shell Kaluza-Klein towers (either two KK-gravitons, or two radion/KK-dilatons, or one of each), finding that it is possible to obtain the observed relic abundance via thermal freeze-out for Dark Matter masses in the range $m_{\mathrm{DM}}\in [1,15]$ TeV for a 5-dimensional gravitational scale $M_5$ ranging from 5 to a few hundreds of TeV, even after taking into account the bounds from LHC Run II and irrespectively of the DM particle spin.

    hep-phastro-ph.HEJHEP(2020)·25 citations
24. 24*

    Stellar Profile Independent Determination of the Dark Matter Distribution of the Fornax Local Group Dwarf Spheroidal Galaxy

    Sasha Brownsberger🇺🇸 · Lisa Randall🇺🇸

    The local group dwarf spheroidal galaxies (LG dSphs) are among the most promising astrophysical targets for probing the small scale structure of dark matter (DM) subhalos. We describe a method for testing the correspondence between proposed DM halo models and observations of stellar populations within LG dSphs. By leveraging the gravitational potential of any proposed DM model and the available stellar kinematical data, we can derive a prediction for the observed stellar surface density of an LG dSph that can be directly compared with observations. Because we do not make any reference to an assumed surface brightness profile, our model can be applied to exotic DM distributions that produce atypical stellar density distributions. We use our methodology to determine that the DM halo of the Fornax LG dSph is more likely cored than cusped, ascertain that it is characterized by a semi-minor to semi-major axis ratio in minor tension with simulations, and find no substantial evidence of a disk within the dSph's larger DM halo.

    ↳ astro-ph.GAgr-qchep-phMNRAS(2021)·5 citations
25. 25*

    Detuning primordial black hole dark matter with early matter domination and axion monodromy

    Guillermo Ballesteros🇪🇸 · Julián Rey🇪🇸 · Fabrizio Rompineve🇺🇸

    We present a scenario that ameliorates the tuning problems present in models of primordial black hole dark matter from inflation. Our setup employs the advantages of gravitational collapse in a long epoch of early matter domination with reheating temperature $\lesssim 10^6\text{GeV}$. Furthermore, we make use of a string-inspired class of models where the inflaton is identified with a non-compact axion field. In this framework, the presence of multiple local minima in the inflaton potential can be traced back to an approximate discrete shift symmetry. This scenario allows the formation of primordial black holes in the observationally viable range of masses ($M_{\text{PBH}}\sim 10^{-13}{M}_{\odot }-10^{-16}{M}_{\odot }$) accounting for all dark matter, and in excellent agreement with the CMB. Crucially, we find a significant reduction in the required tuning of the parameters of the inflationary potential, in contrast to the standard case of primordial black hole formation during radiation domination. However, abundant formation of light PBHs during an early phase of matter domination can be more easily in conflict with evaporation bounds. We discuss how these can be avoided under mild assumptions on the collapsing energy density fraction.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2020)·62 citations
26. 26*

    Strings, extended objects, and the classical double copy

    Walter D. Goldberger🇺🇸 · Jingping Li🇺🇸

    We extend Shen's recent formulation (arXiv:1806.07388) of the classical double copy, based on explicit color-kinematic duality, to the case of finite-size sources with non-zero spin. For the case of spinning Yang-Mills sources, the most general consistent double copy consists of gravitating objects which carry pairs of spin degrees of freedom. We find that the couplings of such objects to background fields match those of a classical (i.e. heavy) closed bosonic string, suggesting a string theory interpretation of sources related by color-kinematics duality. As a special case, we identify a limit, corresponding to unoriented strings, in which the 2-form Kalb-Ramond axion field decouples from the gravitational side of the double copy. Finally, we apply the classical double copy to extended objects, described by the addition of finite-size operators to the worldline effective theory. We find that consistency of the color-to-kinematics map requires that the Wilson coefficients of tidal operators obey certain relations, indicating that the extended gravitating objects generated by the double copy of Yang-Mills are not completely generic.

    ↳ hep-thgr-qchep-phJHEP(2020)·72 citations
27. 27*

    Primordial black holes and gravitational waves in nonstandard cosmologies

    Sukannya Bhattacharya🇮🇳 · Subhendra Mohanty🇮🇳 · Priyank Parashari🇮🇳

    For primordial black holes (PBHs) to form a considerable fraction of cold dark matter, the required amplitude of primordial scalar perturbations is quite large ($P_{\zeta }(k)\sim 10^{-2}$) if PBH is formed in radiation epoch. In alternate cosmological histories, where additional epoch of arbitrary equation of state precede radiation epoch, the dynamics of PBH formation and relevant mass ranges can be different leading to lower requirement of primordial power at smaller scales of inflation. Moreover, this alternate history can modify the predictions for the gravitational wave (GW) spectrum, which can be probed by upcoming GW observations. In this paper, we show that an early kination epoch can lead to per cent level abundance ofPBH for a lower amplitude of $P_{\zeta }(k)$ compared to PBH formation in a standard radiation epoch. Moreover, we calculate the effect of early kination epoch on the GW spectrum for first and second orders in perturbation theory which show enhancement in the amplitude of the GW spectrum in a kination epoch with respect to that in a standard radiation epoch.

    ↳ astro-ph.COhep-phPRD(2020)·59 citations
28. 28*

    Generality of Starobinsky and Higgs inflation in the Jordan frame

    Swagat S. Mishra🇮🇳 · Daniel Müller🇧🇷 · Aleksey V. Toporensky🇷🇺

    We revisit the problem of generality of Starobinsky and Higgs inflation. The known results obtained in the Einstein frame are generalized for the case of an arbitrary initial energy of the scalar field. These results are compared with the results obtained directly in the Jordan frame, which, to our knowledge, has not been thoroughly explored in the literature previously. We demonstrate that the qualitative picture of initial conditions zone in the $(\varphi ,\dot{\varphi })$ plane, which leads to sufficient amount of inflation, is quite similar for both the frames in the case of Higgs inflation. For Starobinsky inflation, the conformal transformation between the frames relates the geometrical variables in the Jordan frame with the properties of an effective scalar field in the Einstein frame. We show that the transformation $(H,R)\to (\varphi ,\dot{\varphi })$ is not regular everywhere, leading to some peculiarities in the zone of good initial conditions in the $(H,R)$ plane.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·28 citations
29. 29*

    Large $N_c$ behaviour of lattice QCD in the heavy dense regime

    Owe Philipsen🇩🇪 · Jonas Scheunert🇩🇪

    Combining strong coupling and hopping expansion one can derive a dimensionally reduced effective theory of lattice QCD. This theory has a reduced sign problem, is amenable to analytic evaluation and was successfully used to study the cold and dense regime of QCD for sufficiently heavy quarks. We show results from the evaluation of the effective theory for arbitrary $N_c$ up to ${\kappa }^4$. The inclusion of gauge corrections is also investigated. We find that the onset transition to finite baryon number density steepens with growing $N_c$ even for $T\ne 0$. This suggests that in the large $N_c$ limit the onset transition is first order up to the deconfinement transition. Beyond the onset, the pressure is shown to scale as $p\sim N_c$ through three orders in the hopping expansion, which is characteristic for a phase termed quarkyonic matter in the literature.

    ↳ hep-lathep-phPoS(2019)·3 citations
30. 30*

    Four-Point Functions in Momentum Space: Conformal Ward Identities in the Scalar/Tensor case

    Claudio Corianò🇮🇹 · Matteo Maria Maglio🇮🇹 · Dimosthenis Theofilopoulos🇮🇹

    We derive and analyze the conformal Ward identities (CWI's) of a tensor 4-point function of a generic CFT in momentum space. The correlator involves the stress-energy tensor $T$ and three scalar operators $O$ ($TOOO$). We extend the reconstruction method for tensor correlators from 3- to 4-point functions, starting from the transverse traceless sector of the $TOOO$. We derive the structure of the corresponding CWI's in two different sets of variables, relevant for the analysis of the 1-to-3 (1 graviton $\to$ 3 scalars) and 2-to-2 (graviton + scalar $\to$ two scalars) scattering processes. The equations are all expressed in terms of a single form factor. In both cases, we discuss the structure of the equations and their possible behaviors in various asymptotic limits of the external invariants. A comparative analysis of the systems of equations for the $TOOO$ and those for the $OOOO$, both in the general (conformal) and dual-conformal/conformal (dcc) cases, is presented. We show that in all the cases the Lauricella functions are homogenous solutions of such systems of equations, also described as parametric 4K integrals of modified Bessel functions.

    ↳ hep-thhep-phEPJC(2020)·32 citations
31. 31*

    News & Views on a new search for the doubly charmed baryon ${\Xi }_{cc}^{+}$ at the LHC

    Xing-Gang Wu🇨🇳

    Invited "News & Views" for the journal, SCIENCE CHINA: Physics, Mechanics & Astronomy, on a recently new search for the doubly charmed baryon ${\Xi }_{cc}^{+}$ at the LHC, which is done by the LHCb Collaboration, arXiv:1909.12273.

    ↳ hep-exhep-phSCPMA(2020)·11 citations
32. 32*

    Heavy-Light Mesons on the Light Front

    Shuo Tang🇺🇸 · Yang Li🇺🇸 · Pieter Maris🇺🇸 · James P. Vary🇺🇸

    We study the heavy-light mesons within basis light-front quantization. The resulting mass spectra of $D$, $D_s$, $B$, and $B_s$ agree reasonably well with experiments. We also predict states which could be measured in the near future. In the light-front formalism, we calculate the light-front wave functions and additional experimental observables, such as parton distribution functions, distribution amplitudes, and decay constants by means of integrations over light-front wave functions. We also provide ratios of decay constants for selected pseudoscalar meson decays ($D_s$ to $D$ and $B_s$ to $B$) as they may prove to be theoretically more robust and more reliably determined in experiments. We find that our ratios are systematically smaller than existing experiment and other approaches by $5-18\%$.

    ↳ nucl-thhep-phEPJC(2020)·55 citations
33. 33*

    Isospin amplitudes in ${\Lambda }_b^0\to J/\psi \Lambda ({\Sigma }^0)$ and ${\Xi }_b^0\to J/\psi {\Xi }^0(\Lambda )$ decays

    LHCb collaboration: R. Aaij🇳🇱 · C. Abellán Beteta🇨🇭 · T. Ackernley🇬🇧 · B. Adeva🇪🇸 · M. Adinolfi🇬🇧 · H. Afsharnia🇫🇷 · C.A. Aidala🇺🇸 · S. Aiola🇮🇹 · Z. Ajaltouni🇫🇷 · S. Akar🇺🇸 · P. Albicocco🇮🇹 · J. Albrecht🇩🇪 and 896 other authors

    Ratios of isospin amplitudes in hadron decays are a useful probe of the interplay between weak and strong interactions, and allow searches for physics beyond the Standard Model. We present the first results on isospin amplitudes in $b$-baryon decays, using data corresponding to an integrated luminosity of 8.5 fb${}^{-1}$, collected with the LHCb detector in $pp$ collisions at center of mass energies of 7, 8 and 13 TeV. The isospin amplitude ratio $|A_1({\Lambda }_b^0\to J/\psi {\Sigma }^0)/A_0({\Lambda }_b^0\to J/\psi \Lambda )|$, where the subscript on $A$ indicates the final-state isospin, is measured to be less than 1/21.8 at 95\% confidence level. The Cabibbo suppressed ${\Xi }_b^0\to J/\psi \Lambda$ decay is observed for the first time, allowing for the measurement $|A_0({\Xi }_b^0\to J/\psi \Lambda )/A_{1/2}({\Xi }_b^0\to J/\psi {\Xi }^0)|=0.37\pm 0.06\pm 0.02$, where the uncertainties are statistical and systematic, respectively.

    ↳ hep-exhep-phPRL(2020)·17 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.