Tue·Oct 17, 2017Tuesday·October 17, 2017

1. 01*

   The Weizsäcker-Williams distribution of linearly polarized gluons (and its fluctuations) at small x

   Adrian Dumitru🇺🇸 · Vladimir Skokov🇺🇸

   The conventional and linearly polarized Weizsäcker-Williams gluon distributions at small x are defined from the two-point function of the gluon field in light-cone gauge. They appear in the cross section for dijet production in deep inelastic scattering at high energy. We determine these functions in the small-x limit from solutions of the JIMWLK evolution equations and show that they exhibit approximate geometric scaling. Also, we discuss the functional distributions of these WW gluon distributions over the JIMWLK ensemble at rapidity $Y\sim 1/{\alpha }_s$. These are determined by a 2d Liouville action for the logarithm of the covariant gauge function $g^2\mathrm{tr}{A}^{+}(q)A^{+}(-q)$. For transverse momenta on the order of the saturation scale we observe large variations across configurations (evolution trajectories) of the linearly polarized distribution up to several times its average, and even to negative values.

   hep-phEPJ Web Conf.(2018)·6 citations
2. 02*

   TASI Lectures on Indirect Detection of Dark Matter

   Tracy R. Slatyer🇺🇸

   These lectures, presented at TASI 2016: Anticipating the Next Discoveries in Particle Physics, provide an introduction to some key methods and tools of indirect dark matter searches. Topics covered include estimation of dark matter signals, thermal freezeout and related scenarios, potential effects of dark matter annihilation on the early universe, modeling photon signals from annihilation or decay, and a brief and qualitative introduction to diffusive propagation of cosmic rays. The second half of the notes gives a status report (circa summer 2016) on selected experimental searches, the resulting constraints and some potential signal candidates. These notes are intended as an introduction to indirect dark matter searches for graduate students, focusing on back-of-the-envelope estimates and useful concepts rather than detailed quantitative computations.

   hep-phastro-ph.COastro-ph.HE144 citations
3. 03*

   $W^{\prime }$ Pair Production in the Light of CMS Searches

   Saeid Paktinat Mehdiabadi🇮🇷 · Leila Zamiri

   For the first time, the pair production of the heavy charged gauge bosons, known as $W^{\prime }$ bosons is considered, when both decay to $\tau$ leptons. The reported detailed efficiency of object/event selection by the CMS experiment is used to find the lower limit on the mass of $W^{\prime }$ boson. Various assumptions for the coupling of the new gauge boson are examined and the results are reported. In the case of a SM-like $W^{\prime }$ boson, masses below 290 GeV are excluded at 95\% confidence level. The method can be used to constrain the new models with the similar final state.

   hep-phJ.Phys.G(2018)·2 citations
4. 04*

   Neutrino spin oscillations in curved space-time under the influence of external fields

   Maxim Dvornikov (IZMIRAN, Tomsk State University)🇷🇺

   We study neutrino spin oscillations in background matter under the influence of strong electromagnetic and gravitational fields. The neutrino spin evolution is treated quasiclassically. We derive the effective Hamiltonian governing spin oscillations of a neutrino moving in the vicinity of a black hole and interacting with a relativistic magnetized accretion disk around a black hole. Applications for the studies of spin oscillations of astrophysical neutrinos are considered.

   hep-phastro-ph.HEgr-qcJ.Phys.Conf.Ser.(2017)·0 citations
5. 05*

   Neutrino telescope searches for dark matter in the Sun

   Pat Scott🇬🇧

   I give a brief review of a few recent developments and future directions in the search for dark matter using high-energy neutrinos from the Sun. This includes the ability to recast neutrino telescope limits on nuclear scattering of dark matter to arbitrary new theories, and new calculations of the solar atmospheric background relevant to such searches. I also touch on applications to global searches for new physics, and prospects for improving searches for asymmetric dark matter in the Sun.

   hep-phastro-ph.CO2 citations
6. 06*

   An effective field theory for warm QCD

   Sourendu Gupta🇮🇳 · Rishi Sharma🇮🇳

   Using only global symmetries of QCD, we set up an effective model of quarks at finite temperature near the cross over, including all possible terms up to dimension 6. We first treat this in mean field theory. Then we investigate low-energy fluctuations around it up to one-loop order in fermions below the cross over. Static correlation functions of pions and the cross over temperature, both measured on the lattice, completely suffice to fix all parameters of the theory. We examine predictions of this theory, including those for thermodynamic quantities. The results are encouraging.

   hep-phhep-latnucl-thPRD(2018)·15 citations
7. 07*

   Modeling Finite-Volume Effects and Chiral Symmetry Breaking in Two-Flavor QCD Thermodynamics

   Bertram Klein (Technische Universität München)🇩🇪

   Finite-volume effects in Quantum Chromodynamics (QCD) have been a subject of much theoretical interest for more than two decades. They are in particular important for the analysis and interpretation of QCD simulations on a finite, discrete space-time lattice. Most of these effects are closely related to the phenomenon of spontaneous breaking of the chiral flavor symmetry and the emergence of pions as light Goldstone bosons. These long-range fluctuations are strongly affected by putting the system into a finite box, and an analysis with different methods can be organized according to the interplay between pion mass and box size. The finite volume also affects critical behavior at the chiral phase transition in QCD. In the present review, I will be mainly concerned with modeling such finite volume effects as they affect the thermodynamics of the chiral phase transition for two quark flavors. I review recent work on the analysis of finite-volume effects which makes use of the quark-meson model for dynamical chiral symmetry breaking. To account for the effects of critical long-range fluctuations close to the phase transition, most of the calculations have been performed using non-perturbative Renormalization Group (RG) methods. I give an overview over the application of these methods to a finite volume. The method, the model and the results are put into the context of related work in random matrix theory for very small volumes, chiral perturbation theory for larger volumes, and related methods and approaches. They are applied towards the analysis of finite-volume effects in lattice QCD simulations and their interpretation, mainly in the context of the chiral phase transition for two quark flavors.

   hep-phhep-latPhys.Rept.(2017)·45 citations
8. 08*

   The Global Electroweak and Higgs Fits in the LHC era

   Jorge de Blas🇮🇹 · Marco Ciuchini🇮🇹 · Enrico Franco🇮🇹 · Satoshi Mishima🇯🇵 · Maurizio Pierini🇨🇭 · Laura Reina🇺🇸 · Luca Silvestrini🇮🇹

   We update the global fit to electroweak precision observables, including the effect of the latest measurements at hadron colliders of the $W$ and top-quark masses and the effective leptonic weak mixing angle. We comment on the impact of these measurements in terms of constraints on new physics. We also update the bounds derived from the fit to the Higgs-boson signal strengths, including the observables measured at the LHC Run 2, and compare the improvements with respect to the 7 and 8 TeV results.

   hep-phhep-exPoS(2017)·56 citations
9. 09*

   The effect of quantum fluctuations in compact star observables

   Péter Pósfay🇭🇺 · Gergely Gábor Barnaföldi🇭🇺 · Antal Jakovác🇭🇺

   Astrophysical measurements regarding compact stars are just ahead of a big evolution jump, since the NICER experiment deployed on ISS on 14 June 2017. This will soon provide data that would enable the determination of compact star radius with less than 10% error. This poses new challenges for nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars. Detailed studies of the QCD phase diagram shows the importance of bosonic quantum fluctuations in the cold dense matter equation of state. Here, we using a demonstrative model to show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius, and compactness. We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above mentioned quantities are calculated in mean field, one-loop and in high order many-loop approximation. The results show that the magnitude of these effects is ~5%, which place it into the region where forthcoming high-accuracy measurements may detect it.

   hep-phastro-ph.HEgr-qcnucl-thPubl.Astron.Soc.Austral.(2018)·4 citations
10. 10*

    An open window to neutrino mass hierarchy at maximal Dirac CP violation

    Ying Zhang🇨🇳

    Non-zero leptonic CP phases in the neutrino sector are clear evidence for physics beyond the Standard Model and have many implications in particle physics and cosmology. Some clues to maximal Dirac CP violation ${\delta }_{CP}=3\pi /2$ are reviewed. An approach to connect the Dirac CP violation phase and the neutrino mass hierarchy in terms of the measurement of CP asymmetry is proposed. Under appropriate requirements for baseline distance and beam energy, the problem of neutrino mass hierarchy can be revealed at maximal Dirac CP violation. General allowed parameter spaces are investigated, within which the two unknown neutrino issues, mass hierarchy and Dirac CP violation, can be solved simultaneously. The abilities of addressing the mass hierarchy of current long baseline neutrino experiments are also discussed.

    hep-ph2 citations
11. 11*

    Study of $B_c^{\pm }\to (D^0{K}^{\pm },D^0{\pi }^{\pm })$ decays

    Chuan-Hung Chen🇹🇼 · Yen-Hsun Lin🇹🇼

    LHCb observes the $B_c^{+}\to D^0{K}^{+}$ decay with $R_{D^{0}K}=f_c/f_u\times \mathcal{B}(B_c^{+}\to D^0{K}^{+})=(9.3_{-2.5}^{+2.8}\pm 0.6)\times 10^{-7}$. The corresponding branching ratio (BR) of the decay can be estimated as $\mathcal{B}(B_c^{+}\to D^0{K}^{+})\approx (10.01\pm 3.40)\times 10^{-5}$; however, the theoretical estimates vary from $\sim 10^{-7}$ to $\sim 5\times 10^{-5}$. We phenomenologically investigate the $B_c^{+}\to (D^0{K}^{+},D^0{\pi }^{+})$ decays through the analysis of $B\to KK$, $B_u^{+}\to D^{+}{K}^0$, and $B_d\to D_s^{-}{K}^{+}$. With the form factor of $f_0^{B_{c}D}\approx 0.2$, it is found that the tree-annihilation contribution dominates the $B_c^{+}\to D^0{K}^{+}$ decay, and when $\mathcal{B}(B_u^{+}\to D^{+}{K}^0)\approx (1-3.1)\times 10^{-7}$ is required, we obtain $\mathcal{B}(B_c^{+}\to D^0{K}^{+})\approx (4.4-9)\times 10^{-5}$, and the magnitude of CP asymmetry is lower than approximately $10\%$. Although the $B_c^{+}\to D^0{\pi }^{+}$ decay is dominated by the tree-transition effect, the tree-annihilation also makes an important contribution, where its effect could be around $70\%$ of the tree-transition. It is found that when $\mathcal{B}(B_c^{+}\to D^0{K}^{+})\approx (4.4-9)\times 10^{-5}$ is taken, the BR and CP asymmetry for $B_c^{+}\to D^0{\pi }^{+}$ with the common values of parameters can be $\mathcal{B}(B_c^{+}\to D^0{\pi }^{+})\approx (4.9-8)\times 10^{-6}$ and of the order of one, respectively. Moreover, we conclude $\mathcal{B}(B_c^{+}\to D^{+}{K}^0)\approx \mathcal{B}(B_c^{+}\to D^0{K}^{+})$, and the BRs for $B_c^{+}\to K^{+}{\bar{K}}^0$ and $B_c^{+}\to J/\Psi {\pi }^{+}$ are $(6.99\pm 1.34)\times 10^{-7}$ and $(7.7\pm 1.1)\times 10^{-4}$, respectively.

    hep-phhep-ex2 citations
12. 12*

    Closing in on the Wino LSP via trilepton searches at the LHC

    Waleed Abdallah🇪🇬 · Shaaban Khalil🇪🇬 · Stefano Moretti🇬🇧 · Shoaib Munir🇰🇷

    The neutralino dark matter (DM) predicted by the Minimal Supersymmetric Standard Model (MSSM) has been probed in several search modes at the Large Hadron Collider (LHC), one of the leading ones among which is the trilepton plus missing transverse momentum channel. The experimental analysis of this mode has, however, been designed to probe mainly a bino-like DM, originating in the decays of a pair of next-to-lightest neutralino and lightest chargino, both of which are assumed to be wino-like. In this study, we analyse how this trilepton channel can be tuned for probing also the wino-like DM. We note that, while the mentioned standard production mode generally leads to a relatively poor sensitivity for the wino-like DM, there are regions in the MSSM parameter space where the net yield in the trilepton final state can be substantially enhanced at the LHC with $\sqrt{s}=14$ TeV. This is achieved by taking into account also an alternative channel, pair-production of the wino-like DM itself in association with the heavier chargino, and optimisation of the kinematical cuts currently employed by the LHC collaborations. In particular, we find that the cut on the transverse mass of the third lepton highly suppresses both the signal channels and should therefore be discarded in this DM scenario. We perform a detailed detector-level study of some selected parameter space points that are consistent with the most important experimental constraints, including the recent ones from the direct and indirect DM detection facilities. Our analysis demonstrates the high complementarity of the two channels, with their combined significance reaching above 4$\sigma$ for a wino-like DM mass around 100 GeV, with an integrated luminosity as low as 100 fb${}^{-1}$.

    hep-phJHEP(2018)·2 citations
13. 13*

    Diffusion of massive particles around an Abelian-Higgs string

    Abhisek Saha🇮🇳 · Soma Sanyal🇮🇳

    We study the diffusion of massive particles in the space time of an Abelian Higgs string. The particles in the early universe plasma execute Brownian motion. This motion of the particles is modeled as a two dimensional random walk in the plane of the Abelian Higgs string. The particles move randomly in the space time of the string according to their geodesic equations. We observe that for certain values of their energy and angular momentum, an overdensity of particles is observed close to the string. We find that the string parameters determine the distribution of the particles. We make an estimate of the density fluctuation generated around the string as a function of the deficit angle. Though the thickness of the string is small, the length is large and the overdensity close to the string may have cosmological consequences in the early universe.

    hep-phastro-ph.COJCAP(2018)·7 citations
14. 14*

    A quantum information theoretic quantity sensitive to the neutrino mass-hierarchy

    Javid Naikoo🇮🇳 · Ashutosh Kumar Alok🇮🇳 · Subhashish Banerjee🇮🇳 · S. Uma Sankar🇮🇳 · Giacomo Guarnieri🇨🇿 · Christiane Schultze🇦🇹 · Beatrix C. Hiesmayr🇦🇹

    In this work, we derive a quantum information theoretic quantity similar to the Leggett-Garg inequality, which can be defined in terms of neutrino transition probabilities. For the case of ${\nu }_{\mu }\to {\nu }_e/{\bar{\nu }}_{\mu }\to {\bar{\nu }}_e$ transitions, this quantity is sensitive to CP violating effects as well as the neutrino mass-hierarchy, namely which neutrino mass eigenstate is heavier than the other ones. The violation of the inequality for this quantity shows an interesting dependence on mass-hierarchy. For normal (inverted) mass-hierarchy, it is significant for ${\nu }_{\mu }\to {\nu }_e$ (${\bar{\nu }}_{\mu }\to {\bar{\nu }}_e$) transitions. This is applied to the two ongoing accelerator experiments T$2$K and NO$\nu$A as well as the future experiment DUNE.

    hep-phquant-phNPB(2020)·57 citations
15. 15*

    CP violation in 2HDM and EFT: the ZZZ vertex

    Hermès Bélusca-Maïto🇭🇷 · Adam Falkowski🇫🇷 · Duarte Fontes🇵🇹 · Jorge. C. Romão🇵🇹 · João P. Silva🇵🇹

    We study the CP violating ZZZ vertex in the two-Higgs doublet model, which is a probe of a Jarlskog-type invariant in the extended Higgs sector. The form factor $f_4^Z$ is evaluated at one loop in a general $R_{\xi }$ gauge and its magnitude is estimated in the realistic parameter space. Then we turn to the decoupling limit of the two-Higgs doublet model, where the extra scalars are heavy and the physics can be described by the Standard Model supplemented by higher-dimensional operators. The leading operator contributing to $f_4^Z$ at one loop is identified. The CP violating ZZZ vertex is not generated in the effective theory by dimension-8 operators, but instead arises only at the dimension-12 level, which implies an additional suppression by powers of the heavy Higgs mass scale.

    hep-phJHEP(2018)·24 citations
16. 16*

    Status of new physics in CP violation and rare B decays

    Joaquim Matias🇪🇸

    We briefly report on some particular aspects of new physics searches concerning, on the one side, the CKM paradigm and, on the other, the global fit to rare $b\to s\ell \ell$ observables including lepton flavour universality ones. We put special emphasis on the state-of-the-art of hadronic uncertainties of $b\to s\mu \mu$ observables and LFUV in SM and in presence of New Physics. Finally, we discuss the latest experimental and theoretical developments concerning long-distance charm contributions.

    hep-ph1 citation
17. 17*

    Study of Spin through Gluon Poles

    I.V. Anikin🇷🇺 · L. Szymanowski🇵🇱 · O.V. Teryaev🇷🇺 · N. Volchanskiy🇷🇺

    Based on the use of contour gauge and collinear factorization, we propose a new set of single spin asymmetry which can be measured in polarized Drell-Yan process by SPD@NICA. We stress that the discussed single transverse spin asymmetries exist owing to the gluon poles manifesting in the twist-3 or twist-2$\otimes$twist-3 parton distributions related to the transverse-polarized Drell-Yan process.

    hep-phJ.Phys.Conf.Ser.(2017)·1 citation
18. 18*

    Tests for the extraction of Boer-Mulders functions

    Ekaterina Christova🇧🇬 · Elliot Leader🇬🇧 · Michail Stoilov🇧🇬

    At present, the Boer-Mulders (BM) functions are extracted from asymmetry data using the simplifying assumption of their proportionality to the Sivers functions for each quark flavour. Here we present two independent tests for this assumption. We subject COMPASS data on semi-inclusive deep inelastic scattering on the $⟨\cos {\varphi }_h⟩$, $⟨\cos 2{\varphi }_h⟩$ and Sivers asymmetries to these tests. Our analysis shows that the tests are satisfied with the available data if the proportionality constant is the same for all quark flavours, which does not correspond to the flavour dependence used in existing analyses. This suggests that the published information on the BM functions may be unreliable. The $⟨\cos {\varphi }_h⟩$ and $⟨\cos 2{\varphi }_h⟩$ asymmetries receive contributions also from the, in principle, calculable Cahn effect. We succeed in extracting the Cahn contributions from experiment (we believe for the first time) and compare with their calculated values, with interesting implications.

    hep-phJ.Phys.Conf.Ser.(2017)·0 citations
19. 19*

    Linearly-polarized small-x gluons in forward heavy-quark pair production

    Cyrille Marquet🇫🇷 · Claude Roiesnel🇫🇷 · Pieter Taels🇫🇷

    We use the Color Glass Condensate (CGC) framework to study the production of forward heavy quark-antiquark pairs in unpolarized proton-nucleus or proton-proton collisions in the small-x regime. In the limit of nearly back-to-back jets, the CGC result simplifies into the transverse-momentum dependent (TMD) factorization approach. For massless quarks, the TMD factorization formula involves three unpolarized gluon TMDs: the Weizsäcker-Williams gluon distribution, the adjoint-dipole gluon distribution, and an additional one. When quark masses are kept non-zero, three new gluon TMDs appear -- each partnered to one of the aforementioned distributions -- which describe the distribution of linearly-polarized gluons in the unpolarized small-x target. We show how these six gluon TMDs emerge from the CGC formulation and we determine their expressions in terms of Wilson line correlators. We calculate them analytically in the McLerran-Venugopalan model, and further evolve them towards smaller values of x using a numerical implementation of JIMWLK evolution.

    hep-phPRD(2018)·81 citations
20. 20*

    Pion-nucleus Drell-Yan data as a novel constraint for nuclear PDFs

    Petja Paakkinen🇫🇮 · Kari J. Eskola🇫🇮 · Hannu Paukkunen🇫🇮

    We have studied the prospects of using the Drell-Yan dilepton process in pion-nucleus collisions as a novel input in the global analysis of nuclear parton distribution functions (nPDFs). In a NLO QCD framework, we find the measured nuclear cross-section ratios from the NA3, NA10 and E615 experiments to be largely insensitive to the pion parton distributions and also compatible with the EPS09 and nCTEQ15 nPDFs. These data sets can thus be, and in EPPS16 have been, included in global nPDF analyses without introducing significant new theoretical uncertainties or tension with the other data. In particular, we explore the constraining power of these data sets on the possible flavour asymmetry in the valence-quark nuclear modifications. Moreover, using the COMPASS kinematics we present predictions for pion charge-difference ratio, a new measurable which could help to further constrain this asymmetry.

    hep-phhep-exPoS(2018)·5 citations
21. 21*

    EPPS16 - First nuclear PDFs to include LHC data

    Kari J. Eskola🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮 · Carlos A. Salgado🇪🇸

    We present results of our recent EPPS16 global analysis of NLO nuclear parton distribution functions (nPDFs). For the first time, dijet and heavy gauge boson production data from LHC proton-lead collisions have been included in a global fit. Especially, the CMS dijets play an important role in constraining the nuclear effects in gluon distributions. With the inclusion of also neutrino-nucleus deeply-inelastic scattering and pion-nucleus Drell-Yan data and a proper treatment of isospin-corrected data, we were able to free the flavor dependence of the valence and sea quark nuclear modifications for the first time. This gives us less biased, yet larger, flavor by flavor uncertainty estimates. The EPPS16 analysis indicates no tension between the data sets used, which supports the validity of collinear factorization and universal nPDFs for nuclear hard-collision processes in the kinematical range studied.

    hep-phhep-exPoS(2017)·0 citations
22. 22*

    Majorana Dark Matter in a new B-L model

    Shivaramakrishna Singirala🇮🇳 · Rukmani Mohanta🇮🇳 · Sudhanwa Patra🇮🇳 · Soumya Rao🇵🇱

    We present a comprehensive study of Majorana dark matter in a $U(1{)}_{B-L}$ gauge extension of the standard model, where three exotic fermions with $B-L$ charges as $-4,-4,+5$ are added to make the model free from the triangle gauge anomalies. The enriched scalar sector and the new heavy gauge boson $Z^{\prime },$ associated with the $U(1{)}_{B-L}$ symmetry make the model advantageous to be explored in dual portal scenarios for the search of dark matter signal. Diagonalizing the exotic fermion mass matrix, we obtain the Majorana mass eigenstates, of which the lightest one plays the role of dark matter. Analyzing the effect of two mediators separately, the scalar portal channels give a viable parameter space consistent with relic density from PLANCK data and the direct detection limits from various experiments such as LUX, XENON1T and PandaX. While the $Z^{\prime }$ mediated channels are constrained from relic abundance and LHC searches for $Z^{\prime }$ in the dilepton channel. A massless physical Goldstone boson plays a key role in the scalar portal relic density. Finally, we briefly discuss the neutrino mass generation at one-loop level.

    hep-phJCAP(2018)·26 citations
23. 23*

    Quark Condensate in a Weak Magnetic Field

    Christoph P. Hofmann🇲🇽

    The low-temperature representation for the quark condensate in a weak magnetic field $H$ is known up to two-loop order. Remarkably, at one-loop order, the published series for the quark condensate in the chiral limit and $H\ll T^2$ are inconsistent. Using an alternative representation for the kinematical Bose functions, we derive the series to arbitrary order in $H/T^2$, and also determine which of the published results is correct.

    hep-phhep-lathep-thPRD(2019)·6 citations
24. 24*

    LHC signals of radiatively-induced neutrino masses and implications for the Zee-Babu model

    Julien Alcaide🇪🇸 · Mikael Chala🇪🇸 · Arcadi Santamaria🇪🇸

    Contrary to the see-saw models, extended Higgs sectors leading to radiatively-induced neutrino masses do require the extra particles to be at the TeV scale. However, these new states have often exotic decays, to which experimental LHC searches performed so far, focused on scalars decaying into pairs of same-sign leptons, are not sensitive. In this paper we show that their experimental signatures can start to be tested with current LHC data if dedicated multi-region analyses correlating different observables are used. We also provide high-accuracy estimations of the complicated Standard Model backgrounds involved. For the case of the Zee-Babu model, we show that regions not yet constrained by neutrino data and low-energy experiments can be already probed, while most of the parameter space could be excluded at the 95 % C.L. in a high-luminosity phase of the LHC.

    hep-phhep-exPLB(2018)·22 citations
25. 25*

    $R_{K^{(\ast )}}$ anomaly in type-III 2HDM

    A. Arhrib🇲🇦 · R. Benbrik🇨🇳 · C. H. Chen🇹🇼 · J. K. Parry🇨🇳 · L. Rahili🇲🇦 · S. Semlali🇲🇦 · Q. S. Yan🇨🇳

    Recent experimental results provided by the CMS and LHCb, Belle and BaBar collaborations are showing a tension with the SM predictions in $R_{K^{(\ast )}}$, which might call for an explanation from new physics. In this work, we examine this tension in the type-III two-Higgs doublet models. We focus on the contributions of charged Higgs boson to the observable(s) $R_{K^{(\ast )}}$ and other rare processes $\Delta M_q$ ($q=s,d$), $B\to X_s\gamma$ $B_s\to {\mu }^{+}{\mu }^{-}$ and $B_q\to X_s{\mu }^{+}{\mu }^{-}$, which are governed by the same effective Hamiltonian. It is found that regions of large $\tan \beta$ and light charged Higgs mass $m_{H^{\pm }}$ can explain the measured value of $R_{K^{(\ast )}}$ and accommodate other B physics data as well. In contrast, the type-II two-Higgs doublet model can not.

    hep-ph18 citations
26. 26*

    Resonances in a sudden chemical freeze-out model

    Viktor Begun🇵🇱

    The prediction for $p_T$ spectra of various resonances produced in Pb+Pb collisions at 2.76 TeV at the LHC in equilibrium and non-equilibrium models is made. It includes the $\eta$, $\rho$(770), $\Sigma$(1385), $\Lambda$(1520), and $\Xi$(1530). The apparent differences may allow to distinguish between the models.

    hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2018)·2 citations
27. 27*

    Parton distributions with small-x resummation: evidence for BFKL dynamics in HERA data

    Richard D. Ball🇬🇧 · Valerio Bertone🇳🇱 · Marco Bonvini🇮🇹 · Simone Marzani🇮🇹 · Juan Rojo🇳🇱 · Luca Rottoli🇬🇧

    We present a determination of the parton distribution functions of the proton in which NLO and NNLO fixed-order calculations are supplemented by NLLx small-x resummation. Deep inelastic structure functions are computed consistently at NLO+NLLx or NNLO+NLLx, while for hadronic processes small-x resummation is included only in the PDF evolution, with kinematic cuts introduced to ensure the fitted data lie in a region where the fixed-order calculation of the hard cross-sections is reliable. In all other respects, the fits use the same methodology and are based on the same global dataset as the recent NNPDF3.1 analysis. We demonstrate that the inclusion of small-x resummation leads to a quantitative improvement in the perturbative description of the HERA inclusive and charm-production reduced cross-sections in the small x region. The impact of the resummation in our fits is greater at NNLO than at NLO, because fixed-order calculations have a perturbative instability at small x due to large logarithms that can be cured by resummation. We explore the phenomenological implications of PDF sets with small-x resummation for the longitudinal structure function $F_L$ at HERA, for parton luminosities and LHC benchmark cross-sections, for ultra-high energy neutrino-nucleus cross-sections, and for future high-energy lepton-proton colliders such as the LHeC.

    hep-phhep-exnucl-thEPJC(2018)·284 citations
28. 28*

    Axion dark matter search using the storage ring EDM method

    Seung Pyo Chang🇰🇷 · Selcuk Haciomeroglu🇰🇷 · On Kim🇰🇷 · Soohyung Lee🇰🇷 · Seongtae Park🇰🇷 · Yannis K. Semertzidis🇰🇷

    We propose using the storage ring EDM method to search for the axion dark matter induced EDM oscillation in nucleons. The method uses a combination of B and E-fields to produce a resonance between the $g-2$ spin precession frequency and the background axion field oscillation to greatly enhance sensitivity to it. An axion frequency range from $10^{-9}$ Hz to 100 MHz can in principle be scanned with high sensitivity, corresponding to an $f_a$ range of $10^{13}$ GeV $\le f_a\le 10^{30}$ GeV, the breakdown scale of the global symmetry generating the axion or axion like particles (ALPs).

    ↳ hep-exhep-phphysics.ins-detPRD(2019)·62 citations
29. 29*

    Search for Dark Matter Effects on Gravitational Signals from Neutron Star Mergers

    John Ellis🇬🇧 · Andi Hektor🇪🇪 · Gert Hütsi🇪🇪 · Kristjan Kannike🇪🇪 · Luca Marzola🇪🇪 · Martti Raidal🇪🇪 · Ville Vaskonen🇪🇪

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

    ↳ astro-ph.COastro-ph.HEgr-qchep-phPLB(2018)·130 citations
30. 30*

    ${\Lambda }_{c}N$ interaction from lattice QCD and its application to ${\Lambda }_c$ hypernuclei

    Takaya Miyamoto🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Shinya Gongyo🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yoichi Ikeda🇯🇵 · Takashi Inoue🇯🇵 · Takumi Iritani🇯🇵 · Noriyoshi Ishii🇯🇵 · Daisuke Kawai🇯🇵 · Keiko Murano🇯🇵 · Hidekatsu Nemura🇯🇵 · Kenji Sasaki🇯🇵

    The interaction between ${\Lambda }_c$ and a nucleon ($N$) is investigated by employing the HAL QCD method in the (2+1)-flavor lattice QCD on a $(2.9\mathrm{fm}{)}^3$ volume at $m_{\pi }\simeq 410,570,700$ MeV. We study the central potential in ${}^1{S}_0$ channel as well as central and tensor potentials in ${}^3{S}_1-$${}^3{D}_1$ channel, and find that the tensor potential for ${\Lambda }_{c}N$ is negligibly weak and central potentials in both ${}^1{S}_0$ and ${}^3{S}_1-$${}^3{D}_1$ channels are almost identical with each other except at short distances. Phase shifts and scattering lengths calculated with these potentials show that the interaction of ${\Lambda }_{c}N$ system is attractive and has a similar strength in ${}^1{S}_0$ and ${}^3{S}_1$ channels at low energies (i.e. the kinetic energy less than about $40$ MeV). While the attractions are not strong enough to form two-body bound states, our results lead to a possibility to form ${\Lambda }_c$ hypernuclei for sufficiently large atomic numbers ($A$). To demonstrate this, we derive a single-folding potential for ${\Lambda }_c$ hypernuclei from the ${\Lambda }_c$-nucleon potential obtained in lattice QCD, and find that ${\Lambda }_c$ hypernuclei can exist for $A\ge 12$ with the binding energies of a few MeV. We also estimate the Coulomb effect for the ${\Lambda }_c$ hypernuclei.

    ↳ hep-lathep-phnucl-thNPA(2018)·57 citations
31. 31*

    Kinetics of the chiral phase transition in a linear $\sigma$ model

    C. Wesp🇩🇪 · H. van Hees🇩🇪 · A. Meistrenko🇩🇪 · C. Greiner🇩🇪

    We study the dynamics of the chiral phase transition in a linear quark-meson $\sigma$ model using a novel approach based on semiclassical wave-particle duality. The quarks are treated as test particles in a Monte-Carlo simulation of elastic collisions and the coupling to the $\sigma$ meson, which is treated as a classical field. The exchange of energy and momentum between particles and fields is described in terms of appropriate Gaussian wave packets. It has been demonstrated that energy-momentum conservation and the principle of detailed balance are fulfilled, and that the dynamics leads to the correct equilibrium limit. First schematic studies of the dynamics of matter produced in heavy-ion collisions are presented.

    ↳ nucl-thhep-phEPJA(2018)·6 citations
32. 32*

    The effective supergravity of Little String Theory

    Ignatios Antoniadis🇫🇷 · Antonio Delgado🇺🇸 · Chrysoula Markou🇫🇷 · Stefan Pokorski🇵🇱

    In this work we present the minimal supersymmetric extension of the five-dimensional dilaton-gravity theory that captures the main properties of the holographic dual of little string theory. It is described by a particular gauging of $\mathcal{N}=2$ supergravity coupled with one vector multiplet associated to the string dilaton, along the $U(1)$ subgroup of $SU(2)$ R-symmetry. The linear dilaton in the fifth coordinate solution of the equations of motion (with flat string frame metric) breaks half of the supersymmetries to $\mathcal{N}=1$ in four dimensions. The non-supersymmetric version of this model was found recently as a continuum limit of a discretised version of the so-called clockwork setup.

    ↳ hep-thgr-qchep-phEPJC(2018)·14 citations
33. 33*

    Cosmological constraints and comparison of viable $f(R)$ models

    Judit Pérez-Romero🇪🇸 · Savvas Nesseris🇪🇸

    In this paper we present cosmological constraints on several well-known $f(R)$ models, but also on a new class of models that are variants of the Hu-Sawicki one of the form $f(R)=R-\frac{2\Lambda }{1+by(R,\Lambda )}$, that interpolate between the cosmological constant model and a matter dominated universe for different values of the parameter $b$, which is usually expected to be small for viable models and which in practice measures the deviation from General Relativity. We use the latest growth rate, Cosmic Microwave Background, Baryon Acoustic Oscillations, Supernovae type Ia and Hubble parameter data to place stringent constraints on the models and to compare them to the cosmological constant model but also other viable $f(R)$ models such as the Starobinsky or the degenerate hypergeometric models. We find that these kinds of Hu-Sawicki variant parameterizations are in general compatible with the currently available data and can provide useful toy models to explore the available functional space of $f(R)$ models, something very useful with the current and upcoming surveys that will test deviations from General Relativity.

    ↳ astro-ph.COgr-qchep-phPRD(2018)·60 citations
34. 34*

    Model of the Phase Transition Mimicking the Pasta Phase in Cold and Dense Quark-Hadron Matter

    Alexander Ayriyan🇷🇺 · Hovik Grigorian🇷🇺

    A simple mixed phase model mimicking so-called "pasta" phases in the quark-hadron phase transition is developed and applied to static neutron stars for the case of DD2 type hadonic and NJL type quark matter models. The influence of the mixed phase on the mass-radius relation of the compact stars is investigated. Model parameters are chosen such that the results are in agreement with the observational constraints for masses and radii of pulsars.

    ↳ astro-ph.HEhep-phEPJ Web Conf.(2018)·16 citations
35. 35*

    Current and Future White Dwarf Mass-radius Constraints on Varying Fundamental Couplings and Unification Scenarios

    D. M. N. Magano🇵🇹 · J. M. A. Vilas Boas🇵🇹 · C. J. A. P. Martins🇵🇹

    We discuss the feasibility of using astrophysical observations of white dwarfs as probes of fundamental physics. We quantify the effects of varying fundamental couplings on the white dwarf mass-radius relation in a broad class of unification scenarios, both for the simple case of a polytropic stellar structure model and for more general models. Independent measurements of the mass and radius, together with direct spectroscopic measurements of the fine-structure constant in white dwarf atmospheres lead to constraints on combinations of the two phenomenological parameters describing the underlying unification scenario (one of which is related to the strong sector of the theory while the other is related to the electroweak sector). While currently available measurements do not yet provide stringent constraints, we show that forthcoming improvements, expected for example from the Gaia satellite, can break parameter degeneracies and lead to constraints that ideally complement those obtained from local laboratory tests using atomic clocks.

    ↳ astro-ph.COastro-ph.SRgr-qchep-ph+1PRD(2017)·16 citations
36. 36*

    Multimessenger tests of the weak equivalence principle from GW170817 and its electromagnetic counterparts

    Jun-Jie Wei · Bin-Bin Zhang · Xue-Feng Wu · He Gao · Peter Mészáros · Bing Zhang · Zi-Gao Dai · Shuang-Nan Zhang · Zong-Hong Zhu

    The coincident detection of a gravitational-wave (GW) event GW170817 with electromagnetic (EM) signals (e.g., a short gamma-ray burst SGRB 170817A or a macronova) from a binary neutron star merger within the nearby galaxy NGC 4933 provides a new, multimessenger test of the weak equivalence principle (WEP), extending the WEP test with GWs and photons. Assuming that the arrival time delay between the GW signals from GW170817 and the photons from SGRB 170817A or the macronova is mainly attributed to the gravitational potential of the Milky Way, we demonstrate that the strict upper limits on the deviation from the WEP are $\Delta \gamma <1.4\times 10^{-3}$ for GW170817/macronova and $\Delta \gamma <5.9\times 10^{-8}$ for GW170817/SGRB 170817A. A much more severe constraint on the WEP accuracy can be achieved ($\sim 0.9\times 10^{-10}$) for GW170817/SGRB 170817A when we consider the gravitational potential of the Virgo Cluster, rather than the Milky Way's gravity. This provides the tightest limit to date on the WEP through the relative differential variations of the $\gamma$ parameter for two different species of particles. Compared with other multimessenger (photons and neutrinos) results, our limit is 7 orders of magnitude tighter than that placed by the neutrinos and photons from supernova 1987A, and is almost as good as or is an improvement of 6 orders of magnitude over the limits obtained by the low-significance neutrinos correlated with GRBs and a blazar flare.

    ↳ astro-ph.HEgr-qchep-phhep-thJCAP(2017)·41 citations
37. 37*

    Dark Energy after GW170817 and GRB170817A

    Paolo Creminelli🇮🇹 · Filippo Vernizzi🇫🇷

    The observation of GW170817 and its electromagnetic counterpart implies that gravitational waves travel at the speed of light, with deviations smaller than a few $\times 10^{-15}$. We discuss the consequences of this experimental result for models of dark energy and modified gravity characterized by a single scalar degree of freedom. To avoid tuning, the speed of gravitational waves must be unaffected not only for our particular cosmological solution, but also for nearby solutions obtained by slightly changing the matter abundance. For this to happen the coefficients of various operators must satisfy precise relations that we discuss both in the language of the Effective Field Theory of Dark Energy and in the covariant one, for Horndeski, beyond Horndeski and degenerate higher-order theories. The simplification is dramatic: of the three functions describing quartic and quintic beyond Horndeski theories, only one remains and reduces to a standard conformal coupling to the Ricci scalar for Horndeski theories. We show that the deduced relations among operators do not introduce further tuning of the models, since they are stable under quantum corrections.

    ↳ astro-ph.COgr-qchep-phPRL(2017)·913 citations
38. 38*

    Implications of the Neutron Star Merger GW170817 for Cosmological Scalar-Tensor Theories

    Jeremy Sakstein🇺🇸 · Bhuvnesh Jain🇺🇸

    The LIGO/VIRGO collaboration has recently announced the detection of gravitational waves from a neutron star-neutron star merger (GW170817) and the simultaneous measurement of an optical counterpart (the gamma-ray burst GRB 170817A). The close arrival time of the gravitational and electromagnetic waves limits the difference in speed of photons and gravitons to be less than about one part in $10^{15}$. This has three important implications for cosmological scalar-tensor gravity theories that are often touted as dark energy candidates and alternatives to $\Lambda$CDM. First, for the most general scalar-tensor theories---beyond Horndeski models---three of the five parameters appearing in the effective theory of dark energy can now be severely constrained on astrophysical scales; we present the results of combining the new gravity wave results with galaxy cluster observations. Second, the combination with the lack of strong equivalence principle violations exhibited by the supermassive black hole in M87, constrains the quartic galileon model to be cosmologically irrelevant. Finally, we derive a new bound on the disformal coupling to photons that implies that such couplings are irrelevant for the cosmic evolution of the field.

    ↳ astro-ph.COgr-qchep-phhep-thPRL(2017)·775 citations
39. 39*

    Dark Energy after GW170817: dead ends and the road ahead

    Jose María Ezquiaga (1 and 2)🇪🇸 · Miguel Zumalacárregui (2, 3 and 4) ((1) Madrid IFT, (2) UC Berkeley, (3) Nordita, (4) IPhT Saclay)🇺🇸

    Multi-messenger gravitational wave (GW) astronomy has commenced with the detection of the binary neutron star merger GW170817 and its associated electromagnetic counterparts. The almost coincident observation of both signals places an exquisite bound on the GW speed $|c_g/c-1|\le 5\cdot 10^{-16}$. We use this result to probe the nature of dark energy (DE), showing that a large class of scalar-tensor theories and DE models are highly disfavored. As an example we consider the covariant Galileon, a cosmologically viable, well motivated gravity theory which predicts a variable GW speed at low redshift. Our results eliminate any late-universe application of these models, as well as their Horndeski and most of their beyond Horndeski generalizations. Three alternatives (and their combinations) emerge as the only possible scalar-tensor DE models: 1) restricting Horndeski's action to its simplest terms, 2) applying a conformal transformation which preserves the causal structure and 3) compensating the different terms that modify the GW speed (to be robust, the compensation has to be independent on the background on which GWs propagate). Our conclusions extend to any other gravity theory predicting varying $c_g$ such as Einstein-Aether, Hořava gravity, Generalized Proca, TeVeS and other MOND-like gravities.

    ↳ astro-ph.COgr-qchep-phhep-thPRL(2017)·1072 citations
40. 40*

    Detectability of thermal neutrinos from binary-neutron-star mergers and implication to neutrino physics

    Koutarou Kyutoku🇯🇵 · Kazumi Kashiyama🇯🇵

    We propose a long-term strategy for detecting thermal neutrinos from the remnant of binary-neutron-star mergers with a future M-ton water-Cherenkov detector such as Hyper-Kamiokande. Monitoring >~2500 mergers within <~200 Mpc, we may be able to detect a single neutrino with a human-time-scale operation of ~80 Mt years for the merger rate of 1 Mpc^{-3} Myr^{-1}, which is slightly lower than the median value derived by the LIGO-Virgo collaboration with GW170817. Although the number of neutrino events is minimal, contamination from other sources of neutrinos can be reduced efficiently to ~0.03 by analyzing only ~1 s after each merger identified with gravitational-wave detectors if Gadolinium is dissolved in the water. The contamination may be reduced further to ~0.01 if we allow the increase of waiting time by a factor of ~1.7. The detection of even a single neutrino can pin down the energy scale of thermal neutrino emission from binary-neutron-star mergers and could strongly support or disfavor formation of remnant massive neutron stars. Because the dispersion relation of gravitational waves are now securely constrained to that of massless particles with a corresponding limit on the graviton mass of <~10^{-22} eV/c^2 by binary-black-hole mergers, the time delay of a neutrino from gravitational waves can be used to put an upper limit of <~O(10) meV/c^2 on the absolute neutrino mass in the lightest eigenstate. Large neutrino detectors will enhance the detectability, and in particular, 5 Mt Deep-TITAND and 10 Mt MICA planned in the future will allow us to detect thermal neutrinos every ~16 and 8 years, respectively, increasing the significance.

    ↳ astro-ph.HEgr-qchep-phPRD(2018)·51 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.