Mon·Aug 5, 2019Monday·August 5, 2019

1. 01*

   Chiral kinetic theory from the on-shell effective theory: derivation of collision terms

   Stefano Carignano🇪🇸 · Cristina Manuel🇪🇸 · Juan M. Torres-Rincon🇩🇪

   We show that the on-shell effective theory (OSEFT) is the quantum field theory counterpart of a Foldy-Wouthuysen diagonalization of relativistic quantum mechanics for massless fermions. Thus, it is free of the Zitterbewegung oscillations that would yield an ill-defined meaning to the semiclassical transport approach at short distances if derived from the pure Dirac picture. We present a detailed derivation of the collision terms in the chiral kinetic theory using the OSEFT. Collision integrals are derived up to order 1/E, where E is the energy of an on-shell fermion. At this order, the collision terms depends on the spin tensor of the fermion, and in the presence of chiral imbalance, it describes how a massless fermion of a given helicity interacts differently with the transverse photons of different circular polarization. In order to back up our results, we check that they allow us to reproduce the fermion decay rate in an ultradegenerate plasma with a chiral imbalance computed directly from QED.

   hep-phhep-thnucl-thPRD(2020)·37 citations
2. 02*

   Comparison of the EFT Hybrid and Three-Loop Fixed-Order Calculations of the Lightest MSSM Higgs Boson Mass

   E. A. Reyes R.🇨🇴 · A. R. Fazio🇨🇴

   The lightest Higgs boson mass of the Minimal Supersymmetric Standard Model has been recently computed diagrammatically at the three-loop order in the whole supersymmetric parameters space of the SUSY-QCD sector. The code FeynHiggs combines one- and two-loop fixed-order with the effective-field-theory calculations for the same Higgs mass. The two numerical predictions agree considering the scenario of only one SUSY-scale and vanishing stop mixing parameter below 10 TeV. The agreement is improved by introducing an additional supersymmetric scale and a non-zero stop mixing. Additionally, the combined CMS/ATLAS Higgs mass value was used to derive an upper bound on the needed SUSY scale. In the considered scenario, values above the scale $12.5\pm 1.2\mathrm{TeV}$ are excluded.

   hep-phPRD(2019)·14 citations
3. 03*

   Influence of EOS on compact star made of hidden sector nucleons

   Shinji Maedan🇯🇵

   We study compact star made of degenerate hidden sector nucleons which will be a candidate for cold dark matter. A hidden sector like QCD is considered, and as the low energy effective theory we take (hidden sector) $SU(2)$ chiral sigma model including hidden sector vector meson. With the mean field approximation, we find that one can treat the equation of state (EOS) of our model analytically by introducing a variable which depends on the Fermi momentum. The EOS is specified by the two parameters $C_{/sigma}^{\prime }$,$C_{/omega}^{\prime }$, and we discuss how these parameters affect on the mass-radius relation for compact star as well as on the EOS. The dependence of the maximum stable mass of compact stars on the parameter $C_{/sigma}^{\prime }$ will also be discussed.

   hep-phPTEP(2020)·6 citations
4. 04*

   Impact of substructure on local dark matter searches

   Alejandro Ibarra🇩🇪 · Bradley J. Kavanagh🇳🇱 · Andreas Rappelt🇩🇪

   Dark matter substructure can contribute significantly to local dark matter searches and may provide a large uncertainty in the interpretation of those experiments. For direct detection experiments, sub-halos give rise to an additional dark matter component on top of the smooth dark matter distribution of the host halo. In the case of dark matter capture in the Sun, sub-halo encounters temporarily increase the number of captured particles. Even if the encounter happened in the past, the number of dark matter particles captured by the Sun can still be enhanced today compared to expectations from the host halo as those enhancements decay over time. Using results from an analytical model of the sub-halo population of a Milky Way-like galaxy, valid for sub-halo masses between $10^{-5}{M}_{\odot }$ and $10^{11}{M}_{\odot }$, we assess the impact of sub-halos on direct dark matter searches in a probabilistic way. We find that the impact on direct detection can be sizable, with a probability of $\sim 10^{-3}$ to find an $\mathcal{O}(1)$ enhancement of the recoil rate. In the case of the capture rate in the Sun, we find that $\mathcal{O}(1)$ enhancements are very unlikely, with probability $\lesssim 10^{-5}$, and are even impossible for some dark matter masses.

   hep-phastro-ph.GAJCAP(2019)·19 citations
5. 05*

   Probing Trilinear Higgs Self-coupling at the HL-LHC via Multivariate Analysis

   Jung Chang🇰🇷 · Kingman Cheung🇹🇼 · Jae Sik Lee🇰🇷 · Jubin Park🇰🇷

   We perform a multivariate analysis of Higgs-pair production in $HH\to b\bar{b}\gamma \gamma$ channel at the HL-LHC to probe the trilinear Higgs self--coupling ${\lambda }_{3H}$, which takes the value of 1 in the SM. We consider all the known background processes. Also, for the signal we are the first to adopt the most recent event generator of POWHEG-BOX-V2 to exploit the NLO distributions for Toolkit for Multivariate Data Analysis (TMVA), taking account of the full top--quark mass dependence. Through Boosted Decision Tree (BDT) analysis trained for ${\lambda }_{3H}=1$, we find that the significance can reach up to 1.95 with about $9$ signal and $18$ background events. In addition, the Higgs boson self-coupling can be constrained to $1.00<{\lambda }_{3H}<6.22$ at 95\% confidence level (CL). We also perform a likelihood fitting of $M_{\gamma \gamma bb}$ distribution and find the $1\sigma$ confidence interval (CI) of $0.1<{\lambda }_{3H}<2.2\cup 5.4<{\lambda }_{3H}<6.6$ for the ${\lambda }_{3H}=1$ nominal set. On the other hand, using BDTs trained for each value of ${\lambda }_{3H}$, we find a bulk region of $0.5<\sim {\lambda }_{3H}<\sim 4.5$, for which it is hard to pin down the trilinear coupling.

   hep-phPRD(2020)·15 citations
6. 06*

   Rates of $D_0^{\ast }(2400)$, $D_J^{\ast }(3000)$ as the $D_0^{\ast }(2P)$ and $D_0^{\ast }(3P)$ in $B$ Decays

   Xiao-Ze Tan🇨🇳 · Yue Jiang🇨🇳 · Tianhong Wang🇨🇳 · Tian Zhou🇨🇳 · Geng Li🇨🇳 · Zi-Kan Geng🇨🇳 · Guo-Li Wang🇨🇳

   In this paper, we use the instantaneous Bethe-Salpeter method to calculate the semi-leptonic and non-leptonic production of the orbitally excited scalar $D_0^{\ast }$ in $B$ meson decays. When the final state is $1P$ state $D_0^{\ast }(2400)$, our theoretical decay rate is consistent with experimental data. For $D_J^{\ast }(3000)$ final state, which was observed by LHCb collaboration recently and here treated as the orbitally excited scalar $D_0^{\ast }(2P)$, its rate is in the order of $10^{-4}\sim 10^{-6}$. We find the special node structure of $D_0^{\ast }(2P)$ wave function possibly results in the suppression of its branching ratio and the abnormal uncertainty. The $3P$ states production rate is in the order of $10^{-5}$.

   hep-phEPJC(2019)·1 citation
7. 07*

   Dense Quark-Gluon Plasma in strong magnetic fields

   R.A.Abramchuk🇷🇺 · M.A.Andreichikov🇷🇺 · Z.V Khaidukov🇷🇺 · Yu.A.Simonov🇷🇺

   A non-perturbative (np) method of Field Correlators (FCM) was applied to study QCD at temperatures above the deconfinement transition ($1<T/T_c<3,T_c\sim 0.16GeV$) and nonzero baryon densities (baryon chemical potential ${\mu }_B<0.5GeV$) in an external uniform magnetic field ($eB<0.5Ge{V}^2$). Within FCM, the np high-temperature dynamics is embodied in the Polyakov loop and in the Debye mass due to the Color-Magnetic Confinement. Analytic expressions for quark pressure and magnetic susceptibility were obtained. The expressions were represented as series and in integral form. Magnetic susceptibility was found to increase rapidly with temperature and slowly with density. The results at the zero density limit are in agreement with lattice data.

   hep-phEPJC(2019)·12 citations
8. 08*

   Study of ${\bar{B}}_{u,d,s}^{\ast }\to D_{u,d,s}^{\ast }V(V=D_{d,s}^{\ast -},K^{\ast -},{\rho }^{-})$ weak decays

   Qin Chang🇨🇳 · Yunyun Zhang🇨🇳 · Xiaonan Li🇨🇳

   Motivated by the rapid development of heavy flavor physics experiment, we study the tree-dominated nonleptonic ${\bar{B}}_{u,d,s}^{\ast }\to D_{u,d,s}^{\ast }V$~($V=D^{\ast -},D_s^{\ast -},K^{\ast -},{\rho }^{-}$) decays within the factorization approach. The relevant transition form factors are calculated by employing the covariant light-front quark model. The helicity amplitudes are calculated and analyzed in detail, and a very clear hierarchy structure $|H_{-0}|\approx 2|H_{00}|>|H_{0-}|\approx |H_{--}|>|H_{0+}|\approx |H_{++}|$ is presented. The branching fractions are computed and discussed. Numerically, the CKM-favored ${\bar{B}}_q^{\ast }\to D_q^{\ast }{\rho }^{-}$ and $D_q^{\ast }{D}_s^{\ast -}$ decays have relatively large branching fractions, $\gtrsim \mathcal{O}(10^{-8})$, and are hopeful to be observed by LHC and Belle-II experiments in the future.

   hep-phCPC(2019)·13 citations
9. 09*

   Light charged Higgs boson with dominant decay to a charm quark and a bottom quark and its search at LEP2 and future $e^{+}{e}^{-}$ colliders

   A.G. Akeroyd🇬🇧 · Stefano Moretti🇬🇧 · Muyuan Song🇬🇧

   The possibility of a light charged Higgs boson $H^{\pm }$ that decays predominantly to $cb$ and with a mass in the range 80 GeV $\le M_{H^{\pm }}\le 90$ GeV is studied in the context of a 3-Higgs Doublet Model (3HDM). Searches for this decay at the Large Hadron Collider (LHC) do not have sensitivity to this mass region at present. It is shown that the searches for $H^{\pm }$ at LEP2 could be supplemented by either one or two $b$-tags, which would enable such large branching ratios for $H^{\pm }\to cb$ to be probed in the above mass region. We comment on the possibility of this 3HDM scenario to explain a slight excess in the searches for $H^{\pm }$ at LEP2, which is best fit by $M_{H^{\pm }}$ of around 90 GeV, and discuss the prospects for detecting $H^{\pm }\to cb$ decays at future $e^{+}{e}^{-}$ colliders.

   hep-phPRD(2020)·20 citations
10. 10*

    Gravitational wave signatures from an extended inert doublet dark matter model

    Avik Paul🇮🇳 · Biswajit Banerjee🇮🇳 · Debasish Majumdar🇮🇳

    We consider a particle dark matter model by extending the scalar sector of the Standard Model by an additional SU(2) scalar doublet which is made "inert" (and stable) by imposing a discrete $Z_2$ symmetry under which the additional scalar doublet is odd (and the SM is even) and it does not develop any vacuum expectation value (VEV). The lightest inert particle (LIP) of this inert doublet model (IDM) can be a viable candidate for Dark Matter. The IDM model is further extended by an additional singlet scalar which is also even under $Z_2$ and develop a VEV on spontaneous symmetry breaking. This additional scalar singlet mixes with SM Higgs and on diagonalisation of the mass matrix two CP even scalar eigenstates are obtained one of which is attributed to the physical Higgs (with mass 125.09 GeV). The LIP is the dark matter candidate in the extended model. For such a particle dark matter model we explore the first-order electroweak phase transition and the consequent production of Gravitational Waves (GW) at that epoch of the early Universe and calculate the intensities and frequencies for such waves. We then investigate the detection possibilities of such GWs at the future spaceborne primordial GW detectors such as eLISA, BBO, ALIA, DECIGO, U-DECIGO and ground-based detector aLIGO.

    hep-phJCAP(2019)·24 citations
11. 11*

    $B\to T$ transition form factors in light-cone sum rules

    T. M. Aliev🇹🇷 · H. Dag🇩🇪 · A. Kokulu🇩🇪 · A. Ozpineci🇹🇷

    We present a new calculation of the semileptonic tree-level and flavor-changing neutral current form factors describing $B$-meson transitions to tensor mesons $T=D_2^{\ast },K_2^{\ast },a_2,f_2$ ($J^P=2^{+}$). We employ the QCD Light-Cone Sum Rules approach with $B$-meson distribution amplitudes. We go beyond the leading-twist accuracy and provide analytically, for the first time, higher-twist corrections for the two-particle contributions up to twist four terms. We observe that the impact of higher twist terms to the sum rules is noticeable. We study the phenomenological implications of our results on the radiative $B\to K_2^{\ast }\gamma$ and semileptonic $B\to D_2^{\ast }\ell {\bar{\nu }}_{\ell }$, $B\to K_2^{\ast }{\ell }^{+}{\ell }^{-}$ decays.

    hep-phhep-exPRD(2019)·20 citations
12. 12*

    Pion photoproduction off nucleons in covariant chiral perturbation theory

    Gustavo H. Guerrero Navarro🇪🇸 · Astrid N. Hiller Blin🇩🇪 · M. J. Vicente Vacas🇪🇸 · De-Liang Yao🇨🇳

    Pion photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta (1232)$ resonance using the $\delta$ counting. The theory is compared to the available data of cross sections and polarization observables for all the charge channels. Most of the necessary low energy constants are well known from the analysis of other processes and the comparison with data strongly constrains some of the still unknown ones. The $\Delta (1232)$ contribution is significant in improving the agreement with data, even at the low energies considered.

    hep-phPRD(2019)·22 citations
13. 13*

    The Dilaton Potential and Lattice Data

    Thomas Appelquist🇺🇸 · James Ingoldby🇺🇸 · Maurizio Piai🇬🇧

    We study an effective field theory (EFT) describing the interaction of an approximate dilaton with a set of pseudo-Nambu-Goldstone bosons (pNGBs). The EFT is inspired by, and employed to analyse, recent results from lattice calculations that reveal the presence of a remarkably light singlet scalar particle. We adopt a simple form for the scalar potential for the EFT, which interpolates among earlier proposals. It describes departures from conformal symmetry, by the insertion of a single operator at leading order in the EFT. To fit the lattice results, the global internal symmetry is explicitly broken, producing a common mass for the pNGBs, as well as a further, additive deformation of the scalar potential. We discuss sub-leading corrections arising in the EFT from quantum loops. From lattice measurements of the scalar and pNGB masses and of the pNGB decay constant, we extract model parameter values, including those that characterise the scalar potential. The result includes the possibility that the conformal deformation is clearly non-marginal. The extrapolated values for the decay constants and the scalar mass would then be not far below the current lattice-determined values.

    hep-phhep-latPRD(2020)·71 citations
14. 14*

    MeV scale model of SIMP dark matter, neutrino mass and leptogenesis

    Subhendra Mohanty🇮🇳 · Ayon Patra🇮🇳 · Tripurari Srivastava🇮🇳

    We consider a simple extension of the Standard Model with two singlet scalar fields and three heavy right-handed neutrinos. One of the scalar fields serves as an MeV scale dark matter and its stability is ensured by the introduction of an extra $Z_2$ symmetry. The second scalar (which is even under the $Z_2$ symmetry) generates the mass term of the scalar, contributes to the $3\to 2$ annihilation process required for the correct relic density of the dark matter and it also contributes to the leptogenesis. The right-handed neutrinos are responsible for the generation of light neutrino masses through Type-I seesaw mechanism. The decay of the heavy right-handed neutrino can generate the lepton asymmetry which can then be converted to baryon asymmetry through sphaleron transitions.

    hep-phastro-ph.COJCAP(2020)·6 citations
15. 15*

    Generalized Threshold Factorization with Full Collinear Dynamics

    Gillian Lustermans🇳🇱 · Johannes K. L. Michel🇩🇪 · Frank J. Tackmann🇩🇪

    Soft threshold factorization has been used extensively to study hadronic collisions. It is derived in the limit where the momentum fractions $x_{a,b}$ of both incoming partons approach $x_{a,b}\to 1$. We present a generalized threshold factorization theorem for color-singlet processes, which holds in the weaker limit of only $x_a\to 1$ for generic $x_b$ (or vice versa), corresponding to the limit of large rapidity but generic invariant mass of the produced color singlet. It encodes the complete soft and/or collinear singular structure in the partonic momentum fractions to all orders in perturbation theory, including in particular flavor-nondiagonal partonic channels at leading power. It provides a more powerful approximation than the classic soft threshold limit, capturing a much larger set of contributions. We demonstrate this explicitly for the Z and Higgs rapidity spectrum to NNLO, and we use it to predict a nontrivial set of its N3LO contributions. Our factorization theorem provides the relevant resummation of large-$x$ logarithms in the rapidity spectrum required for resummation-improved PDF fits. One of our factorization ingredients is a new beam function closely related to the N-jettiness beam function. As a byproduct, we identify the correct soft threshold factorization for rapidity spectra among the differing results in the literature.

    hep-ph48 citations
16. 16*

    Macroscopic Dark Matter Constraints from Bolide Camera Networks

    Jagjit Singh Sidhu🇺🇸 · Glenn Starkman🇺🇸

    Macroscopic dark matter (macros) are a broad class of alternative candidates to particle dark matter. These candidates would transfer energy primarily through elastic scattering, and this linear energy deposition would produce observable signals if a macro were to pass through the atmosphere. We produce constraints for low mass macros from the null observation of bolides formed by a passing macro, across two extensive networks of cameras built originally to observe meteorites. The parameter space that could be probed with planned upgrades to the existing array of cameras in one of these networks still currently in use, the Desert Fireball Network in Australia, is estimated.

    ↳ astro-ph.COastro-ph.IMhep-phPRD(2019)·34 citations
17. 17*

    AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space

    Yousef Abou El-Neaj🇺🇸 · Cristiano Alpigiani🇺🇸 · Sana Amairi-Pyka🇩🇪 · Henrique Araujo🇬🇧 · Antun Balaz🇷🇸 · Angelo Bassi🇮🇹 · Lars Bathe-Peters🇩🇪 · Baptiste Battelier🇫🇷 · Aleksandar Belic🇷🇸 · Elliot Bentine🇬🇧 · Jose Bernabeu🇪🇸 · Andrea Bertoldi🇫🇷 and 120 other authors

    We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. This paper is based on a submission (v1) in response to the Call for White Papers for the Voyage 2050 long-term plan in the ESA Science Programme. ESA limited the number of White Paper authors to 30. However, in this version (v2) we have welcomed as supporting authors participants in the Workshop on Atomic Experiments for Dark Matter and Gravity Exploration held at CERN: ({\tt https://indico.cern.ch/event/830432/}), as well as other interested scientists, and have incorporated additional material.

    ↳ gr-qcastro-ph.IMhep-exhep-ph+1EPJ Quant.Technol.(2020)·456 citations
18. 18*

    A String Theory of Flavor and CP

    Alexander Baur🇩🇪 · Hans Peter Nilles🇩🇪 · Andreas Trautner🇩🇪 · Patrick K.S. Vaudrevange🇩🇪

    Modular transformations of string theory (including the well-known stringy dualities) play a crucial role in the discussion of discrete flavor symmetries in the Standard Model. They are at the origin of CP transformations and provide a unification of CP with traditional flavor symmetries. Here, we present a novel, fully systematic method to reliably compute the unified flavor symmetry of the low-energy effective theory, including enhancements from the modular transformations of string theory. The unified flavor group is non-universal in moduli space and exhibits the phenomenon of "Local Flavor Unification" where different sectors of the theory can be subject to different flavor structures.

    ↳ hep-thhep-phNPB(2019)·143 citations
19. 19*

    Jet overlap in heavy ion collisions at LHC energies and its consequences on jet shape

    Iurii Karpenko🇫🇷 · Joerg Aichelin🇫🇷 · Pol Gossiaux🇫🇷 · Martin Rohrmoser🇵🇱 · Klaus Werner🇫🇷

    Central lead-lead collisions at the LHC energies may pose a particular challenge for jet identification as multiple jets are produced per each collision event. We simulate the jet evolution in central Pb-Pb events at $\sqrt{s_{\mathrm{NN}}}=2.76$ GeV collision energy with EPOS3 initial state, which typically contains multiple hard scatterings in each event. Therefore the partons from different jets have a significant chance to overlap in momentum space. We find that 30% of the jets with $p_{\perp }>50$ GeV, identified by the standard anti-$k_{\perp }$ jet finding algorithm with jet cone size R=0.3, contain `intruder' particles from overlapping generator-level jets. This fraction increases with increasing beam energy and increasing R. The reconstructed momentum of the jet differs from that of the modelled jet by the loss due to jet partons which are outside of the jet cone and by the gain due to intruder partons. The sum of both may be positive or negative. These intruder partons particularly affect the radial jet momentum distribution because they contribute mostly at large angles $\Delta r$ with respect to the jet centre. The study stresses the importance of the jet overlap effect emerging in central lead-lead collisions at the LHC energies, while being negligible in peripheral PbPb or $p$Pb/$pp$ collisions.

    ↳ nucl-thhep-phnucl-exPRC(2020)·0 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.