Wed·Jan 10, 2018Wednesday·January 10, 2018

1. 01*

   Doubly charmed baryon production in heavy ion collisions

   Xiaojun Yao🇺🇸 · Berndt Müller🇺🇸

   We give an estimate of ${\Xi }_{cc}^{++}$ production rate and transverse momentum spectra in relativistic heavy ion collisions. We use Boltzmann transport equations to describe the dynamical evolution of charm quarks and diquarks inside quark-gluon plasma. In-medium formation and dissociation rates of charm diquarks are calculated from potential non-relativistic QCD for the diquark sector. We solve the transport equations by Monte Carlo simulations. For $2.76$ TeV Pb-Pb collisions with $0-10\%$ centrality, the number of ${\Xi }_{cc}^{++}$ produced in the transverse momentum range $0-5$ GeV and rapidity from $-1$ to $1$ is roughly $0.02$ per collision. We repeat the calculation with a melting temperature $250$ MeV above which no diquarks can be formed. The number of ${\Xi }_{cc}^{++}$ produced in the same kinematic region is about $0.0125$ per collision. We discuss how to study diquarks at finite temperature on a lattice and construct the anti-triplet free energy in a gauge invariant but path dependent way. We also comment on extensions of the calculation to other doubly heavy baryons and doubly heavy tetraquarks and the feasibility of experimental measurements.

   hep-phhep-exnucl-exnucl-thPRD(2018)·57 citations
2. 02*

   Electroweak phase transitions in multi-Higgs models: the case of Trinification-inspired THDSM

   Thibault Vieu🇵🇹 · António P. Morais🇵🇹 · Roman Pasechnik🇸🇪

   The rich vacuum structure of multi-Higgs extensions of the Standard Model (SM) may have interesting cosmological implications for the electroweak phase transition (EWPT). As an important example of such class of models, we consider a particularly simple low-energy SM-like limit of a recently proposed Grand-Unified Trinification model with the scalar sector composed of two Higgs doublets and a complex singlet and with a global $\mathrm{U}(1)$ family symmetry. The fermion sector of this model is extended with a family of vector-like quarks which enhances CP violation. With the current study, we aim at exploring the generic vacuum structure and uncovering the features of the EWPT in this model relevant for cosmology. We show the existence of different phase transition patterns providing strong departure from thermal equilibrium. Most of these observations are not specific to the considered model and may generically be expected in other multi-Higgs extensions of the SM.

   hep-phJCAP(2018)·24 citations
3. 03*

   Graphical Structure of Hadronization and Factorization in Hard Collisions

   John Collins🇺🇸 · Ted C. Rogers🇺🇸

   Models of hadronization of hard jets in QCD are often presented in terms of Feynman-graph structures that can be thought of as effective field theory approximations to dynamical non-perturbative physics in QCD. Such models can be formulated as a kind of multiperipheral model. We obtain general constraints on such models in order for them to be self-consistent, and we relate the constraints to the space-time structure of hadronization. We show that appropriate models can be considered as implementing string-like hadronization. When the models are put in a multiperipheral form, the effective vertices and/or lines must be momentum non-conserving: they take 4-momentum from the external string-like field.

   hep-phhep-th6 citations
4. 04*

   Characterising Dark Matter Interacting with Extra Charged Leptons

   D. Barducci🇮🇹 · A. Deandrea🇫🇷 · S. Moretti🇬🇧 · L. Panizzi🇬🇧 · H. Prager🇬🇧

   In the context of a simplified leptophilic Dark Matter (DM) scenario where the mediator is a new charged fermion carrying leptonic quantum number and the DM candidate is either scalar or vector, the complementarity of different bounds is analysed. In this framework, the extra lepton and DM are odd under a ${\mathbb{Z}}_2$ symmetry, hence the leptonic mediator can only interact with the DM state and Standard Model (SM) leptons of various flavours. We show that there is the possibility to characterise the DM spin (scalar or vector), as well as the nature of the mediator, through a combined analysis of cosmological, flavour and collider data. We present an explicit numerical analysis for a set of benchmarks points of the viable parameter space of our scenario.

   hep-phPRD(2018)·10 citations
5. 05*

   Searches for light sterile neutrinos with multitrack displaced vertices

   Giovanna Cottin🇹🇼 · Juan Carlos Helo🇨🇱 · Martin Hirsch🇪🇸

   We study discovery prospects for long-lived sterile neutrinos at the LHC with multitrack displaced vertices, with masses below the electroweak scale. We reinterpret current displaced vertex searches making use of publicly available, parametrized selection efficiencies for modeling the detector response to displaced vertices. We focus on production of right-handed $W_R$ bosons and neutrinos $N$ in a left-right symmetric model, and find poor sensitivity. After proposing a different trigger strategy (considering the prompt lepton accompanying the neutrino displaced vertex) and optimized cuts in the invariant mass and track multiplicity of the vertex, we find that the LHC with $\sqrt{s}=13$ TeV and 300 fb${}^{-1}$ is able to probe sterile neutrino masses between $10\text{mbox}GeV<m_N<20$ GeV (for a right-handed gauge boson mass of $2\text{mbox}TeV<m_{W_R}<3.5$ TeV). To probe higher masses up to $m_N\sim 30$ GeV and $m_{W_R}<5$ TeV, 3000 fb${}^{-1}$ will be needed. This work joins other efforts in motivating dedicated experimental searches to target this low sterile neutrino mass region.

   hep-phhep-exPRD(2018)·94 citations
6. 06*

   Direct Detection of Ultralight Dark Matter via Astronomical Ephemeris

   Hajime Fukuda🇯🇵 · Shigeki Matsumoto🇯🇵 · Tsutomu T. Yanagida🇯🇵

   A novel idea of the direct detection to search for a ultralight dark matter based on the interaction between the dark matter and a nucleon is proposed. Solar system bodies feel the dark matter wind and it acts as a resistant force opposing their motions. The astronomical ephemeris of solar system bodies is so precise that it has a strong capability to detect a dark matter whose mass is much lighter than O(1) eV. We have estimated the resistant force based on the calculation of the elastic scattering cross section between the dark matter and the bodies beyond the Born approximation, and show that the astronomical ephemeris indeed put a very strong constraint on the interaction between the dark matter and a nucleon, depending on how smoothly the ultralight dark matter is distributed at the scale smaller than the celestial bodies in our solar system.

   hep-phastro-ph.COastro-ph.EPPLB(2019)·17 citations
7. 07*

   The role of positron polarization for the inital $250$ GeV stage of the International Linear Collider

   Keisuke Fujii🇯🇵 · Christophe Grojean🇩🇪 · Michael E. Peskin (conveners)🇺🇸 · Tim Barklow🇺🇸 · Yuanning Gao🇨🇳 · Shinya Kanemura🇯🇵 · Hyungdo Kim🇰🇷 · Jenny List🇩🇪 · Mihoko Nojiri🇯🇵 · Maxim Perelstein🇺🇸 · Roman Pöschl🇫🇷 · Jürgen Reuter🇩🇪 and 13 other authors

   The International Linear Collider is now proposed with a staged machine design, with the first stage at $\sqrt{s}=$~250 GeV and an integrated luminosity goal of 2~ab${}^{-1}$. One of the questions for the machine design is the importance of positron polarization. In this report, we review the impact of positron polarization on the physics goals of the $250$ GeV stage of the ILC and demonstrate that positron polarization has distinct advantages.

   hep-phhep-ex62 citations
8. 08*

   Perturbed flavour symmetries and predictions of CP violating phase $\delta$

   Anjan S. Joshipura🇮🇳

   It is known that the imposition of a class of residual $Z_2\times Z_2$ symmetries on the neutrino mass matrix $M_{\nu }$ and a residual symmetry $Z_n$ ($n\ge 3$) on the Hermitian combination $M_l{M}_l^{†}$ of the charged lepton mass matrix leads to a universal prediction of vanishing Dirac CP phase $\delta$ if these symmetries are embedded in $\Delta (6n^2)$ groups and if the leptonic doublets transform as a 3 dimensional irreducible representation of the group. The Majorana phases remain arbitrary but they can also be determined in $\Delta (6n^2)$ by imposing generalized CP symmetry (GenCP) consistent with the $\Delta (6n^2)$ group. We investigate the effects of adding general perturbations on these predictions assuming that perturbations break the $Z_2\times Z_2$ symmetry completely but preserve GenCP. It is found that if the residual symmetries predict the tri-bimaximal mixing (TBM) among leptons and specific CP conserving values for the Majorana phases then addition of the above perturbations always lead to a neutrino mass matrix invariant under the $\mu$-$\tau$ reflection symmetry in the flavour basis with the result that perturbations turn the vanishing $\delta$ into maximal value $\pm \frac{\pi }{2}.$ One gets non-vanishing but generally large $\delta$ if the predicted zeroeth order mixing deviates from TBM and/or the predicted Majorana phases are non-trivial. We systematically investigate effects of perturbations in such situations and work out the predicted $\delta$ for four of the lowest $\Delta (6n^2)$ groups with $n=2,4,6,8.$

   hep-ph6 citations
9. 09*

   Vector leptoquark mass limits and branching ratios of $K_L^0,B^0,B_s\to l_i^{+}{l}_j^{-}$ decays with account of fermion mixing in leptoquark currents

   A. D. Smirnov🇷🇺

   The contributions of the vector leptoquarks of Pati-Salam type to the branching ratios of $K_L^0,B^0,B_s\to l{l}^{\prime }$ decays are calculated with account of the fermion mixing in the leptoguark currents of the general type. Using the general parametrizations of the mixing matrices the lower vector leptoquark mass limit $m_V>86TeV$ is found from the current experimental data on these decays. The branching ratios of the decays $B^0,B_s\to l{l}^{\prime }$ predicted at $m_V=86TeV$ are calculated. These branching ratios for the decays $B^0,B_s\to {\mu }^{+}{\mu }^{-},e\mu$ are close to the experimental data whereas those for the decays $B^0\to e^{+}{e}^{-},e\tau ,\mu \tau$, and $B_s\to e^{+}{e}^{-}$ are by order of $2÷4$ less than their current experimental limits. For the decays $B_s\to e\tau ,\mu \tau$ these branching ratios are of order $10^{-10}$ and $10^{-9}$ respectively. The predicted branching ratios will be usefull in the current and future experimental searches for these decays.

   hep-phhep-exMod.Phys.Lett.A(2018)·49 citations
10. 10*

    Prediction on Neutrino Dirac and Majorana Phases and Absolute Mass Scale from the CKM Matrix

    Naoyuki Haba🇯🇵 · Toshifumi Yamada🇯🇵

    In Type-I seesaw model, the lepton flavor mixing matrix (PMNS matrix) and the quark flavor mixing matrix (CKM matrix) may be connected implicitly through a relation between the neutrino Dirac Yukawa coupling $Y_D$ and the quark Yukawa couplings. In this paper, we study whether $Y_D$ can satisfy, in the flavor basis where the charged lepton Yukawa and right-handed neutrino Majorana mass matrices are diagonal, the relation $Y_D\propto \mathrm{diag}(y_d,y_s,y_b)V_{CKM}^T$ or $Y_D\propto \mathrm{diag}(y_u,y_c,y_t)V_{CKM}^{\ast }$ without contradicting the current experimental data on quarks and neutrino oscillations. We search for sets of values of the neutrino Dirac CP phase ${\delta }_{CP}$, Majorana phases ${\alpha }_2,{\alpha }_3$, and the lightest active neutrino mass that satisfy either of the above relations, with the normal or inverted hierarchy of neutrino mass. In performing the search, we consider renormalization group evolutions of the quark masses and CKM matrix and the propagation of their experimental errors along the evolutions. We find that only the former relation $Y_D\propto \mathrm{diag}(y_d,y_s,y_b)V_{CKM}^T$ with the normal neutrino mass hierarchy holds, based on which we make a prediction for ${\delta }_{CP},{\alpha }_2,{\alpha }_3$ and the lightest active neutrino mass.

    hep-phPRD(2018)·1 citation
11. 11*

    Explaining DAMA with proton-philic spin-dependent inelastic Dark Matter (pSIDM): a frequentist analysis

    Seong-Hyeong Kang🇰🇷 · Stefano Scopel🇰🇷 · Jong-Hyun Yoon (Sogang U.)🇰🇷

    Proton-philic spin-dependent inelastic Dark Matter is a Weakly Inelastic Massive Particle scenario that can explain the DAMA yearly modulation effect in compliance with the constraints from other direct detection Dark Matter searches. We obtain updated ranges for its parameters both in a halo-independent approach and adopting a truncated Maxwellian for the WIMP velocity distribution constructing approximate frequentist confidence intervals from an effective chi-square including, among others, the latest experimental constraints from XENON1T, PANDAX-II, SuperCDMS and CDMSlite. In the halo-independent analysis we have implemented the dependence on the WIMP velocity distribution through a step-wise parameterization of the halo function. For the calculation of the profile likelihood we used a Markov Chain Montecarlo generator that required a large number of evaluations of the expected rates. To reduce computational time we introduced expected rates expressions suitable for a fast evaluation through tabulation and interpolation. Our frequentist analysis confirms the present viability of the pSIDM scenario as a possible explanation of the DAMA effect. In terms of the WIMP mass $m_{\chi }$ and of the mass splitting $\delta$ we find the 1-sigma ranges $\text{mbox}12.5GeV\le m_{\chi }\le \text{mbox}15.7GeV$, $\text{mbox}22.1keV\le \delta \le \text{mbox}26.1keV$ for the halo--independent analysis and $\text{mbox}11.4GeV\le m_{\chi }\le \text{mbox}13.6GeV$, $\text{mbox}24.4keV\le \delta \le \text{mbox}27.0keV$ for the Maxwellian case. We find that a full year of data taking of XENON1T should allow to start probing the pSIDM scenario.

    hep-ph1 citation
12. 12*

    Magnetic Polarizability of Virtual (ss') and (cc') Pairs in the Nucleon

    Peter Filip🇸🇰

    We suggest 3P0 quantum state of virtual (ss') pairs in the nucleon can be polarised by the internal fields permeating the volume of the nucleon (proton or neutron). Due to the quadratic Zeeman interaction, 3P0 wavefunction of virtual (qq') pairs acquires the admixture of 1P10 quantum state in the magnetic field, which generates the antiparallel polarization of s and s' quarks (in the nucleon). Considering the internal magnetic fields of neutron and proton (originating from their measured magnetic dipole moments), we suggest the induced s-quark polarization in the neutron to be of the oposite direction compared to the proton case. We mention the influence of the internal chromo-magnetic fields on the quantum state of (qq') pairs in the nucleon and we discuss also the expected behaviour of virtual (cc') pairs.

    hep-phJ.Phys.Conf.Ser.(2017)·0 citations
13. 13*

    Interplay of colour kinematics duality and analytic calculation of multi-loop scattering amplitudes: one and two loops

    William J. Torres Bobadilla🇪🇸

    In this talk, we review recent developments towards the calculation of multi-loop scattering amplitudes. In particular, we discuss how the colour-kinematics duality can provide new integral relations at one-loop level via the Loop-Tree duality formalism. On the other hand, in order to compute scattering amplitudes at one- and two-loop level, numerically and analytically, we describe the preliminary automation of the adaptive integrand decomposition algorithm. We show preliminary results on the analytic reduction of the $\mu e$-elastic scattering at one- and two-loop level.

    hep-phhep-thPoS(2018)·4 citations
14. 14*

    Parton distribution functions from reduced Ioffe-time distributions

    Jian-Hui Zhang🇩🇪 · Jiunn-Wei Chen🇹🇼 · Christopher Monahan🇺🇸

    We show that the correct way to extract parton distribution functions from the reduced Ioffe-time distribution (RITD), a ratio of the Ioffe-time distribution for a moving hadron and a hadron at rest, is through a factorization formula. This factorization exists because, at small distances, forming the ratio does not change the infrared behavior of the numerator, which is factorizable. We illustrate the effect of such a factorization by applying it to results in the literature.

    hep-phhep-latPRD(2018)·79 citations
15. 15*

    The method of global R* and its applications

    K. G. Chetyrkin🇩🇪 · G. Falcioni🇳🇱 · F. Herzog🇳🇱 · J. A. M. Vermaseren🇳🇱

    The global R* operation is a powerful method for computing renormalisation group functions. This technique, based on the principle of infrared rearrangement, allows to express all the ultraviolet counterterms in terms of massless propagator integrals. In this talk we present the main features of global R* and its application to the renormalisation of QCD. By combining this approach with the use of the program Forcer for the evaluation of the relevant Feynman integrals, we renormalise for the first time QCD at five loops in covariant gauges.

    hep-phPoS(2018)·8 citations
16. 16*

    Connecting CMB anisotropy and cold dark matter phenomenology via reheating

    Debaprasad Maity🇮🇳 · Pankaj Saha🇮🇳

    Understanding the properties of dark matter has proved to be one of the most challenging problems of particle phenomenology. In this paper, we have tried to understand the phenomenology of dark matter in light of very well understood properties of cosmic microwave background (CMB) anisotropy. To connect these two, inflation and its subsequent evolution known as the reheating phase play the important role. Following the previous analysis, we first established a one-to-one correspondence between the CMB power spectrum and the reheating temperature assuming the perturbative reheating scenario. Further by incorporating a possible dark matter candidate through the radiation annihilation process during reheating and the current value of dark matter abundance, we constrain the dark matter parameter space through the inflationary power spectrum for different inflationary models.

    hep-phgr-qcPRD(2018)·59 citations
17. 17*

    XYZ - SU3 Breakings from Laplace Sum Rule at Higher Orders: Summary

    R. Albuquerque (FAT, UERJ, Rio de Janeiro, BR)🇧🇷 · S. Narison (LUPM-CNRS, Montpellier, FR)🇫🇷 · D. Rabetiarivony🇲🇬 · G. Randriamanatrika (iHEPMAD, Antananarivo, MG)🇲🇬

    This talk reviews and summarizes some of our results in [1] on XYZ- SU3 Breakings obtained from QCD Laplace Sum Rules (LSR) at next-to-next-leading order (N2LO) of perturbative (PT) theory and including next-to-leading order (NLO) SU3 breaking corrections and leading order (LO) contributions of dimensions d< (6 - 8) non-perturbative condensates. We conclude that the observed X states are good candidates for being 1^++ and 0^++ molecules states. We find that the SU3 breakings are relatively small for the masses (< 10 (resp. 3) %) for the charm (resp. bottom) channels while they are large (< 20 %) for the couplings. Like in the chiral limit case, the couplings decrease faster: 1/m_b^3/2 than 1/m_b^1/2 of HQET. Our approach cannot clearly separate ( within the errors ) some molecule states from the four-quark ones with the same quantum numbers.

    hep-phhep-exhep-lat1 citation
18. 18*

    Prospects for indirect detection of frozen-in dark matter

    Matti Heikinheimo🇫🇮 · Tommi Tenkanen🇬🇧 · Kimmo Tuominen🇫🇮

    We study observational consequences arising from dark matter (DM) of non-thermal origin, produced by dark freeze-out from a hidden sector heat bath. We assume this heat bath was populated by feebly-coupled mediator particles, produced via a Higgs portal interaction with the Standard Model (SM). The dark sector then attained internal equilibrium with a characteristic temperature different from the SM photon temperature. We find that even if the coupling between the DM and the SM sectors is very weak, the scenario allows for indirect observational signals. We show how the expected strength of these signals depends on the temperature of the hidden sector at DM freeze-out.

    hep-phastro-ph.COastro-ph.HEPRD(2018)·28 citations
19. 19*

    The ratio $R=\mathrm{d}{\sigma }_L/\mathrm{d}{\sigma }_T$ in heavy-quark pair leptoproduction as a probe of linearly polarized gluons in unpolarized proton

    A.V. Efremov🇷🇺 · N.Ya. Ivanov🇦🇲 · O.V. Teryaev🇷🇺

    We study the Callan-Gross ratio $R=\mathrm{d}{\sigma }_L/\mathrm{d}{\sigma }_T$ in heavy-quark pair leptoproduction, $lN\to l^{\prime }Q\bar{Q}X$, as a probe of linearly polarized gluons inside unpolarized proton, where $\mathrm{d}{\sigma }_T$ ($\mathrm{d}{\sigma }_L$) is the differential cross section of the ${\gamma }^{\ast }N\to Q\bar{Q}X$ process initiated by a transverse (longitudinal) virtual photon. Note first that the maximal value for the quantity $R$ allowed by the photon-gluon fusion with unpolarized gluons is large, about 2. We calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer-Mulders function, $h_1^{\perp g}$, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum value of the ratio $R$ depends strongly on the gluon polarization; it varies from 0 to $\frac{Q^2}{4m^2}$ depending on $h_1^{\perp g}$. We conclude that the Callan-Gross ratio in heavy-quark pair leptoproduction is predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the longitudinal and transverse components of the charm and bottom production cross sections at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton.

    hep-phPLB(2018)·16 citations
20. 20*

    Statistically Anisotropic Tensor Modes from Inflation

    Tomohiro Fujita🇯🇵 · Ippei Obata🇯🇵 · Takahiro Tanaka🇯🇵 · Shuichiro Yokoyama🇯🇵

    We consider the inflationary universe with a spectator scalar field coupled to a $U(1)$ gauge field and calculate curvature perturbation and gravitational waves (GWs). We find that the sourced GWs can be larger than the one from vacuum fluctuation and they are statistically anisotropic as well as linearly polarized. The GW power spectrum acquires higher multipole moments as ${\mathcal{P}}_h\propto (1-{\cos }^2\theta +{\cos }^4\theta -{\cos }^6\theta )$ irrespective of the model parameters.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2018)·33 citations
21. 21*

    Stability and Critical Behavior of Gravitational Monopoles

    Ben Kain🇺🇸

    I dynamically evolve spherically symmetric spacetimes containing gravitational 't Hooft-Polyakov monopoles and determine the stable end states of the evolutions. I do so to study stability and critical behavior of the well-known static gravitational monopole solutions. For the static solutions, there exist regions of parameter space where two static monopole black holes and the static Reissner-Nordstrom black hole have the same mass. I find strong evidence that one of the static monopole black hole solutions is a critical solution, to which near-critical solutions are dynamically attracted before evolving to one of the other two static solutions as end states. I also discuss the no-hair conjecture for this model in the context of collapse.

    ↳ gr-qchep-phhep-thPRD(2018)·4 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.