Mon·Aug 24, 2015Monday·August 24, 2015

1. 01*

   Consistent constraints on the Standard Model Effective Field Theory

   Laure Berthier🇩🇰 · Michael Trott🇩🇰

   We develop the global constraint picture in the (linear) effective field theory generalisation of the Standard Model, incorporating data from detectors that operated at PEP, PETRA, TRISTAN, SpS, Tevatron, SLAC, LEPI and LEP II, as well as low energy precision data. We fit one hundred and three observables. We develop a theory error metric for this effective field theory, which is required when constraints on parameters at leading order in the power counting are to be pushed to the percent level, or beyond, unless the cut off scale is assumed to be large, $\Lambda \gtrsim 3\mathrm{TeV}$. We more consistently incorporate theoretical errors in this work, avoiding this assumption, and as a direct consequence bounds on some leading parameters are relaxed. We show how an $\mathrm{S},\mathrm{T}$ analysis is modified by the theory errors we include as an illustrative example.

   hep-phJHEP(2016)·133 citations
2. 02*

   Holographic Approach to Deep Inelastic Scattering at Small-x at High Energy

   Richard C. Brower🇺🇸 · Marko Djurić🇵🇹 · Timothy Raben🇺🇸 · Chung-I Tan🇺🇸

   We focus on a holographic approach to DIS at small-x in high energy where scattering is dominated by exchanging a Reggeized Graviton in $Ad{S}_5$. We emphasize the importance of confinement, which corresponds to a deformation of $Ad{S}_5$ geometry in the IR. This approach provides an excellent fit to the combined HERA data at small $x$. We also discuss the connection of Pomeron/Odderon intercepts in the conformal limit with anomalous dimensions in strong coupling.

   hep-phPoS(2015)·4 citations
3. 03*

   Exotic $\mu \tau jj$ events from heavy ISS neutrinos at the LHC

   E. Arganda🇪🇸 · M.J. Herrero🇪🇸 · X. Marcano🇪🇸 · C. Weiland🇪🇸

   In this letter we study new relevant phenomenological consequences of the right-handed heavy neutrinos with masses at the $\mathcal{O}(1)$ TeV energy scale, working within the context of the Inverse Seesaw Model that includes three pairs of quasi-degenerate pseudo-Dirac heavy neutrinos. We propose a new exotic signal of these heavy neutrinos at the CERN Large Hadron Collider containing a muon, a tau lepton, and two jets in the final state, which is based on the interesting fact that this model can incorporate large Lepton Flavor Violation for specific choices of the relevant parameters, particularly, the neutrino Yukawa couplings. We will show here that an observable number of $\mu \tau jj$ exotic events, without missing energy, can be produced at this ongoing run of the LHC.

   hep-phPLB(2016)·61 citations
4. 04*

   Correct Definition of the Gluon Fragmentation Function at High Energy Colliders

   Gouranga C. Nayak

   Since the definition of the gluon to hadrons fragmentation amplitude $<H,X|g>$ involves gluon field $Q^{\mu a}(x)$ corresponding to single gluon incoming state $|g>$, the present definition of the gluon fragmentation function at high energy colliders [which involves non-abelian field tensor $F^{\mu \nu a}(x)={\partial }^{\mu }{Q}^{\nu a}(x)-{\partial }^{\nu }{Q}^{\mu a}(x)+g{f}^{abc}{Q}^{\mu b}(x)Q^{\nu c}(x)$ instead of $Q^{\mu a}(x)$ in the initial state] is not consistent with the single gluon incoming state $|g>$. In this paper we derive the correct definition of the gluon fragmentation function at high energy colliders from first principles which is obtained from the single gluon incoming state $|g>$ and is gauge invariant and is consistent with the factorization theorem in QCD.

   hep-phhep-exnucl-th2 citations
5. 05*

   Baryogenesis in a CP invariant theory

   Anson Hook🇺🇸

   We consider baryogenesis in a model which has a CP invariant Lagrangian, CP invariant initial conditions and does not spontaneously break CP at any of the minima. We utilize the fact that tunneling processes between CP invariant minima can break CP to implement baryogenesis. CP invariance requires the presence of two tunneling processes with opposite CP breaking phases and equal probability of occurring. In order for the entire visible universe to see the same CP violating phase, we consider a model where the field doing the tunneling is the inflaton.

   hep-phJHEP(2015)·11 citations
6. 06*

   Unitarity and the three flavour neutrino mixing matrix

   Stephen Parke🇺🇸 · Mark Ross-Lonergan🇬🇧

   Unitarity is a fundamental property of any theory required to ensure we work in a theoretically consistent framework. In comparison with the quark sector, experimental tests of unitarity for the 3x3 neutrino mixing matrix are considerably weaker. It must be remembered that the vast majority of our information on the neutrino mixing angles originates from ${\overline{\nu }}_e$ and ${\nu }_{\mu }$ disappearance experiments, with the assumption of unitarity being invoked to constrain the remaining elements. New physics can invalidate this assumption for the 3x3 subset and thus modify our precision measurements. We perform a reanalysis to see how global knowledge is altered when one refits oscillation results without assuming unitarity, and present $3\sigma$ ranges for allowed $U_{\text{PMNS}}$ elements consistent with all observed phenomena. We calculate the bounds on the closure of the six neutrino unitarity triangles, with the closure of the ${\nu }_e{\nu }_{\mu }$ triangle being constrained to be $\le$ 0.03, while the remaining triangles are significantly less constrained to be $\le$ 0.1 - 0.2. Similarly for the row and column normalization, we find their deviation from unity is constrained to be $\le$ 0.2 - 0.4, for four out of six such normalisations, while for the ${\nu }_{\mu }$ and ${\nu }_e$ row normalisation the deviations are constrained to be $\le$ 0.07, all at the $3\sigma$ CL. We emphasise that there is significant room for new low energy physics, especially in the ${\nu }_{\tau }$ sector which very few current experiments constrain directly.

   hep-phPRD(2016)·150 citations
7. 07*

   Flavour Changing Higgs Couplings in a Class of Two Higgs Doublet Models

   F.J. Botella (Valencia U. & Valencia U., IFIC)🇪🇸 · G.C. Branco (Lisbon, IST & Valencia U. & Valencia U., IFIC)🇵🇹 · M. Nebot🇵🇹 · M.N. Rebelo (Lisbon, IST)🇵🇹

   We analyse various flavour changing processes like $t\to hu,hc$, $h\to \tau e,\tau \mu$ as well as hadronic decays $h\to bs,bd$, in the framework of a class of two Higgs doublet models where there are flavour changing neutral scalar currents at tree level. These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as $\tan \beta$. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and therefore it is natural and stable under the renormalization group. We show that in some of the models the rates of the above flavour changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular $\mu \to e\gamma$.

   hep-phEPJC(2016)·136 citations
8. 08*

   Features of electroweak symmetry breaking in five dimensional SUSY models

   Zygmunt Lalak🇵🇱 · Marek Lewicki🇵🇱 · Moritz McGarrie🇵🇱 · Paweł Olszewski🇵🇱

   We explore the phenomenological predictions of a supersymmetric standard model, with a large extra dimension and unifying gauge couplings. The modified five dimensional renormalisation group equations make it possible to obtain light, maximally mixed stops, with a low scale of supersymmetry breaking and a low unification scale. This allows the fine-tuning to be lowered right down to the barrier coming directly from experimental lower limits on the stop masses. We also show that attempts at modifying the SUSY breaking pattern to obtain more natural soft terms at the high scale do not give the expected fine-tuning relaxation, and only RGE effects turn out to be effective in generating a lower fine-tuning.

   hep-phJHEP(2015)·3 citations
9. 09*

   Can A Pseudo-Nambu-Goldstone Higgs Lead To Symmetry Non-Restoration?

   Can Kilic🇺🇸 · Sivaramakrishnan Swaminathan🇺🇸

   The calculation of finite temperature contributions to the scalar potential in a quantum field theory is similar to the calculation of loop corrections at zero temperature. In natural extensions of the Standard Model where loop corrections to the Higgs potential cancel between Standard Model degrees of freedom and their symmetry partners, it is interesting to contemplate whether finite temperature corrections also cancel, raising the question of whether a broken phase of electroweak symmetry may persist at high temperature. It is well known that this does not happen in supersymmetric theories because the thermal contributions of bosons and fermions do not cancel each other. However, for theories with same spin partners, the answer is less obvious. Using the Twin Higgs model as a benchmark, we show that although thermal corrections do cancel at the level of quadratic divergences, subleading corrections still drive the system to a restored phase. We further argue that our conclusions generalize to other well-known extensions of the Standard Model where the Higgs is rendered natural by being the pseudo-Nambu-Goldstone mode of an approximate global symmetry.

   hep-phJHEP(2016)·26 citations
10. 10*

    Production asymmetries of $D^{\pm }$, ${\Lambda }_c^{+}/{\Lambda }_c^{-}$ and ${\Lambda }_b^0/{\overline{\Lambda }}_b^0$ at the LHC from heavy quark recombination mechanism

    Wai Kin Lai🇺🇸

    The asymmetry in the forward region production cross section of $D^{\pm }$ is calculated using the heavy quark recombination mechanism for $pp$ collisions at $7$~TeV. By suitable choices of four nonperturbative parameters, our calculated results can reproduce those obtained at LHCb. We find $A_p\sim -1\%$ when integrated over $2.0\text{ GeV}<p_T<18\text{ GeV}$ and $2.2<\eta <4.75$, which agrees with $A_p=-0.96\pm 0.26\pm 0.18\%$ as measured by LHCb. Furthermore, the calculated distributions in $\eta$ and $p_T$ agree reasonably well with those obtained at LHCb. Using the heavy quark recombination mechanism, we also make predictions on the production asymmetries of ${\Lambda }_c^{+}/{\Lambda }_c^{-}$ and ${\Lambda }_b^0/{\overline{\Lambda }}_b^0$ for $pp$ collisions at $7$~TeV and $14$~TeV in the forward region. We find that the integrated asymmetries for these $\Lambda$ baryons in the LHCb region are of the order of $\sim 1-3\%$ and should be measurable.

    hep-ph0 citations
11. 11*

    Anisotropic emission of thermal dielectrons from Au+Au collisions at $\sqrt{s_{NN}}=200$~GeV with EPOS3

    Sheng-Xu Liu🇨🇳 · Fu-Ming Liu🇨🇳 · Klaus Werner🇫🇷 · Meng Yue🇨🇳

    Dileptons, as an electromagnetic probe, are crucial to study the properties of a Quark-Gluon Plasma (QGP) created in heavy ion collisions. We calculated the invariant mass spectra and the anisotropic emission of thermal dielectrons from Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) energy $\sqrt{s_{NN}}=200$~GeV based on EPOS3. This approach provides a realistic (3+1)-dimensional event-by-event viscous hydrodynamic description of the expanding hot and dense matter with a very particular initial condition, and a large set of hadron data and direct photons (besides $v_2$ and $v_3$ !) can be successfully reproduced. Thermal dilepton emission from both the QGP phase and the hadronic gas are considered, with the emission rates based on Lattice QCD and a vector meson model, respectively. We find that the computed invariant mass spectra (thermal contribution + STAR cocktail) can reproduce the measured ones from STAR at different centralities. Different compared to other model predictions, the obtained elliptic flow of thermal dileptons is larger than the STAR measurement referring to all dileptons. We observe a clear centrality dependence of thermal dilepton not only for elliptic flow $v_2$ but also for higher orders. At a given centrality, $v_n$ of thermal dileptons decreases monotonically with $n$ for $2\le n\le 5$.

    hep-phnucl-th0 citations
12. 12*

    Small-x, Diffraction and Vector Mesons

    T. Lappi🇫🇮

    This talk discusses recent progress in some topics relevant for deep inelastic scattering at small x. We discuss first differences and similarities between conventional collinear factorization and the dipole picture of deep inelastic scattering. Many of the recent theoretical advances at small x are related to taking calculations in the nonlinear saturation regime to next-to-leading order accuracy in the QCD coupling. On the experimental side significant recent progress has been made in exclusive and diffractive processes, in particular in ultraperipheral nucleus-nucleus collisions.

    hep-phnucl-thPoS(2015)·0 citations
13. 13*

    Scale-Invariant Hidden Local Symmetry, Topology Change and Dense Baryonic Matter

    Won-Gi Paeng🇰🇷 · Thomas T. S. Kuo🇺🇸 · Hyun Kyu Lee🇰🇷 · Mannque Rho🇫🇷

    When scale symmetry is implemented into hidden local symmetry in low-energy strong interactions to arrive at a scale-invariant hidden local symmetric (HLS) theory, the scalar $f_0(500)$ may be interpreted as pseudo-Nambu-Goldstone (pNG) boson, i.e., dilaton, of spontaneously broken scale invariance, joining the pseudo-scalar pNG bosons $\pi$ and the matter fields $V=(\rho ,\omega )$ as relevant degrees of freedom. Implementing the skyrmion-half-skyrmion transition predicted at large $N_c$ in QCD at a density roughly twice the nuclear matter density found in the crystal simulation of dense skyrmion matter, we determine the intrinsically density-dependent (IDD) "bare parameters" of the scale-invariant HLS Lagrangian matched to QCD at a matching scale ${\Lambda }_M$. The resulting effective Lagrangian, with the parameters scaling with the density of the system, is applied to nuclear matter and dense baryonic matter relevant to massive compact stars by means of the double-decimation renormalization-group $V_{lowk}$ formalism. We satisfactorily post-dict the properties of normal nuclear matter and more significantly {\it predict} the EoS of dense compact-star matter that quantitatively accounts for the presently available data coming from both the terrestrial and space laboratories. We interpret the resulting structure of compact-star matter as revealing how the combination of hidden-scale symmetry and hidden local symmetry manifests itself in compressed baryonic matter.

    hep-phnucl-thPRC(2016)·48 citations
14. 14*

    Maximal Zero Textures in Linear and Inverse Seesaw

    Roopam Sinha🇮🇳 · Rome Samanta🇮🇳 · Ambar Ghosal🇮🇳

    We investigate Linear and Inverse seesaw mechanisms with maximal zero textures of the constituent matrices subjected to the assumption of non-zero eigenvalues for the neutrino mass matrix $m_{\nu }$ and charged lepton mass matrix $m_e$. If we restrict to the minimally parametrized non-singular `$m_e$' (i.e., with maximum number of zeros) it gives rise to only 6 possible textures of $m_e$. Non-zero determinant of $m_{\nu }$ dictates six possible textures of the constituent matrices. We ask in this minimalistic approach, what are the phenomenologically allowed maximum zero textures are possible. It turns out that Inverse seesaw leads to 7 allowed two-zero textures while the Linear seesaw leads to only one. In Inverse seesaw, we show that 2 is the maximum number of independent zeros that can be inserted into ${\mu }_S$ to obtain all 7 viable two-zero textures of $m_{\nu }$. On the other hand, in Linear seesaw mechanism, the minimal scheme allows maximum 5 zeros to be accommodated in `$m$' so as to obtain viable effective neutrino mass matrices ($m_{\nu }$). Interestingly, we find that our minimalistic approach in Inverse seesaw leads to a realization of all the phenomenologically allowed two-zero textures whereas in Linear seesaw only one such texture is viable. Next our numerical analysis shows that none of the two-zero textures give rise to enough CP violation or significant ${\delta }_{CP}$. Therefore, if ${\delta }_{CP}=\pi /2$ is established, our minimalistic scheme may still be viable provided we allow more number of parameters in `$m_e$'.

    hep-phPLB(2016)·21 citations
15. 15*

    What triggers ${\theta }_{13}$ discrepancy between Daya Bay and T2K?

    Naoyuki Haba🇯🇵 · Hiroyuki Ishida🇯🇵 · Kyousuke Shimada🇯🇵 · Yuya Yamaguchi🇯🇵

    There seems to be a non-negligible discrepancy between Daya Bay and T2K experimental results of a neutrino mixing angle, ${\theta }_{13}$ . We show the discrepancy can be simply passed away even in the standard three neutrinos framework by taking the same value of $\Delta m_{32}^2$ with a normal neutrino mass hierarchy and Dirac CP phase $\delta =-\pi /2$, which is favorable in T2K experiment. For numerical analyses of neutrino oscillation probabilities, there are five independent parameters, $\Delta m_{21}^2$, $\Delta m_{32}^2$, ${\theta }_{12}$, ${\theta }_{23}$, and $\delta$. We reevaluate ${\theta }_{13}$ by scatter plots within $1\sigma$ range of five-dimensional parameters space suggested by PDG, T2K, and Daya Bay. We project onto $\delta$-${\sin }^{2}2{\theta }_{13}$ plane and find an overlap area of ${\theta }_{13}$ suggested by T2K and Daya Bay. In the normal hierarchy case, the largest overlap area is given by parameters set suggested by T2K, and the overlap area becomes small in order of parameters sets suggested by PDG and Daya Bay. In the inverted hierarchy case, there is a tiny overlap area only in parameters set suggested by T2K. We also show several sample points of four parameters set, $\Delta m_{21}^2$, $\Delta m_{32}^2$, ${\theta }_{12}$, and ${\theta }_{23}$, where the dissonance of ${\theta }_{13}$ is really disappeared with $\delta =-\pi /2$.

    hep-phhep-ex0 citations
16. 16*

    Thermal transport of the solar captured dark matter and its impact on the indirect dark matter search

    Chian-Shu Chen🇹🇼 · Guey-Lin Lin🇹🇼 · Yen-Hsun Lin🇹🇼

    We study the thermal transport occurring in the system of solar captured dark matter (DM) and explore its impact on the DM indirect search signal. We particularly focus on the scenario of self-interacting DM (SIDM). The flows of energies in and out of the system are caused by solar captures via DM-nucleon and DM-DM scatterings, the energy dissipation via DM annihilation, and the heat exchange between DM and solar nuclei. We examine the DM temperature evolution and demonstrate that the DM temperature can be higher than the core temperature of the Sun if the DM-nucleon cross section is sufficiently small such that the energy flow due to DM self-interaction becomes relatively important. We argue that the correct DM temperature should be used for accurately predicting the DM annihilation rate, which is relevant to the DM indirect detection.

    hep-phPhys.Dark Univ.(2016)·9 citations
17. 17*

    A set of top quark spin correlation and polarization observables for the LHC: Standard Model predictions and new physics contributions

    Werner Bernreuther🇩🇪 · Dennis Heisler🇩🇪 · Zong-Guo Si🇨🇳

    We consider top-antitop quark ($t\bar{t}$) production at the Large Hadron Collider (LHC) with subsequent decay into dileptonic and lepton plus jets final states. We present a set of leptonic angular correlations and distributions with which experiments can probe all the independent coefficient functions of the top-spin dependent parts of the $t\bar{t}$ production spin density matrices. We compute these angular correlations and distributions for LHC center-of-mass energies 8, 13, and 14 TeV within the Standard Model at next-to-leading order in the QCD coupling including the mixed QCD-weak corrections and for the transverse top-quark polarization and the $t\bar{t}$ charge asymmetry also the mixed QCD-QED corrections. In addition we analyze and compute the effects of new interactions on these observables in terms of a gauge-invariant effective Lagrangian which contains all operators relevant for hadronic $t\bar{t}$ production up to mass dimension six.

    hep-phhep-exJHEP(2015)·181 citations
18. 18*

    Form factors of B, Bs -> eta, eta' and D, Ds -> eta, eta' transitions from QCD light-cone sum rules

    Goran Duplancic🇭🇷 · Blazenka Melic🇭🇷

    In the framework of the QCD light-cone sum rules (LCSRs) we present the analysis of all $B,B_s\to {\eta }^{(\prime )}$ and $D,D_s\to {\eta }^{(\prime )}$ form factors ($f^{+},f^0$ and $f^T$) by including $m_{{\eta }^{(\prime )}}^2$ corrections in the leading (up to the twist-four) and next-to-leading order (up to the twist-three) in QCD, and two-gluon contributions to the form factors at the leading twist. The SU(3)-flavour breaking corrections and the axial anomaly contributions to the distribution amplitudes are also consistently taken into account. The complete results for the $f^0$ and $f^T$ form factors of $B,B_s\to {\eta }^{(\prime )}$ and $D,D_s\to {\eta }^{(\prime )}$ relevant for processes like $B\to {\eta }^{(\prime )}\tau {\nu }_{\tau }$ or $B_s\to {\eta }^{(\prime )}{l}^{+}{l}^{-}$ are given for the first time, as well as the two-gluon contribution to the tensor form factors. The values obtained for the $f^{+}$ form factors are as follows: $f_{B\eta }^{+}(0)=0.168_{-0.047}^{+0.042}$, $|f_{B_s\eta }^{+}(0)|=0.212_{-0.013}^{+0.015}$, $f_{B{\eta }^{\prime }}^{+}(0)=0.130_{-0.032}^{+0.036}$, $f_{B_s{\eta }^{\prime }}^{+}(0)=0.252_{-0.020}^{+0.023}$ and $f_{D\eta }^{+}(0)=0.429_{-0.141}^{+0.165}$, $|f_{D_s\eta }^{+}(0)|=0.495_{-0.029}^{+0.030}$, $f_{D{\eta }^{\prime }}^{+}(0)=0.292_{-0.104}^{+0.113}$, $f_{D_s{\eta }^{\prime }}^{+}(0)=0.558_{-0.045}^{+0.047}$. Also phenomenological predictions for semileptonic $B,B_s\to {\eta }^{(\prime )}$ and $D,D_s\to {\eta }^{(\prime )}$ decay modes are given.

    hep-phhep-exhep-latJHEP(2015)·73 citations
19. 19*

    Debye mass at the QCD transition in the PNJL model

    J. Jankowski🇵🇱 · D. Blaschke🇷🇺 · O. Kaczmarek🇩🇪

    We consider colour-electric screening as expressed by the quark contribution to the Debye mass calculated in a PNJL model with emphasis on confining and chiral symmetry breaking effects. We observe that the screening mass is entirely determined by the nonperturbative quark distribution function and temperature dependent QCD running coupling. The role of the gluon background (Polyakov loop) is to provide strong suppression of the number of charge carriers below the transition temperature, as an effect of confinement, while the temperature dependent dynamical quark mass contributes additional suppression, as an effect of chiral symmetry breaking. An alternative derivation of this result from a modified kinetic theory is given, which allows for a slight generalization and explicit contact with perturbative QCD. This gives the possibility to gain insights into the colour screening mechanism in the region near the QCD pseudocritical temperature and to provide a guideline for the interpretation of lattice QCD data.

    hep-phhep-lathep-thnucl-th3 citations
20. 20*

    Higher-order QCD predictions for dark matter production at the LHC in simplified models with s-channel mediators

    Mihailo Backović🇧🇪 · Michael Krämer🇩🇪 · Fabio Maltoni🇧🇪 · Antony Martini🇧🇪 · Kentarou Mawatari🇧🇪 · Mathieu Pellen🇩🇪

    Weakly interacting dark matter particles can be pair-produced at colliders and detected through signatures featuring missing energy in association with either QCD/EW radiation or heavy quarks. In order to constrain the mass and the couplings to standard model particles, accurate and precise predictions for production cross sections and distributions are of prime importance. In this work, we consider various simplified models with s-channel mediators. We implement such models in the FeynRules/MadGraph5_aMC@NLO framework, which allows to include higher-order QCD corrections in realistic simulations and to study their effect systematically. As a first phenomenological application, we present predictions for dark matter production in association with jets and with a top-quark pair at the LHC, at next-to-leading order accuracy in QCD, including matching/merging to parton showers. Our study shows that higher-order QCD corrections to dark matter production via s-channel mediators have a significant impact not only on total production rates, but also on shapes of distributions. We also show that the inclusion of next-to-leading order effects results in a sizeable reduction of the theoretical uncertainties.

    hep-phEPJC(2015)·152 citations
21. 21*

    Indirect determinations of the top quark mass

    Gian F. Giudice🇨🇭 · Paride Paradisi🇮🇹 · Alessandro Strumia🇮🇹

    We give a complete analysis of indirect determinations of the top quark mass in the Standard Model by introducing a systematic procedure to identify observables that receive quantum corrections enhanced by powers of $M_t$. We propose to use flavour physics as a tool to extract the top quark mass. Although present data give only a poor determination, we show how future theoretical and experimental progress in flavour physics can lead to an accuracy in $M_t$ well below 2 GeV. We revisit determinations of $M_t$ from electroweak data, showing how an improved measurement of the $W$ mass leads to an accuracy well below 1 GeV.

    hep-phJHEP(2015)·15 citations
22. 22*

    Antineutrino flux from the Laguna Verde Nuclear Power Plant

    Marisol Chavez-Estrada🇲🇽 · Alexis A. Aguilar-Arevalo🇲🇽

    We present a calculation of the antineutrino flux produced by the reactors at the Laguna Verde Nuclear Power Plant in México, based on the antineutrino spectra produced in the decay chains of the fission fragments of the main isotopes in the reactor core, and their fission rates, that have been calculated using the DRAGON simulation code. We also present an estimate of the number of expected events in a detector made of plastic scintillator with a mass of 1 ton, at 100 m from the reactor cores.

    ↳ physics.ins-dethep-exhep-phAdv.High Energy Phys.(2015)·2 citations
23. 23*

    Dressed scalar propagator in a non-abelian background from the worldline formalism

    Naser Ahmadiniaz🇲🇽 · Fiorenzo Bastianelli🇮🇹 · Olindo Corradini🇲🇽

    We study the propagator of a colored scalar particle in the background of a non-abelian gauge field using the worldline formalism. It is obtained by considering the open worldline of a scalar particle with extra degrees of freedom needed to take into account the color charge of the particle, which we choose to be in the fundamental representation of the gauge group. Specializing the external gauge field to be given by a sum of plane waves, i.e. a sum of external gluons, we produce a master formula for the scalar propagator with an arbitrary number of gluons directly attached to the scalar line, akin to similar formulas derived in the literature for the case of the scalar particle performing a loop. Our worldline description produces at the same time the situation in which the particle has a color charge given by an arbitrarily chosen symmetric or antisymmetric tensor product of the fundamental.

    ↳ hep-thhep-phPRD(2016)·41 citations
24. 24*

    Testing the origin of ~3.55 keV line in individual galaxy clusters observed with XMM-Newton

    Dmytro Iakubovskyi🇺🇦 · Esra Bulbul🇺🇸 · Adam R. Foster🇺🇸 · Denys Savchenko🇺🇦 · Valentyna Sadova

    If the unidentified emission line at ~3.55 keV previously found in spectra of nearby galaxies and galaxy clusters is due to radiatively decaying dark matter, one should detect the signal of comparable strength from many cosmic objects of different nature. By studying existing dark matter distributions in galaxy clusters we identified top-19 of them observed by XMM-Newton X-ray cosmic mission, and analyzed the data for the presence of the new line. In 8 of them, we identified > 2 sigma positive line-like residuals with average position 3.52 +/- 0.08 keV in the emitter's frame. Their observed properties are unlikely to be explained by statistical fluctuations or astrophysical emission lines; observed line position in M31 and Galactic Center makes an additional argument against general-type systematics. Being interpreted as decaying dark matter line, the new detections correspond to radiative decay lifetime tau_dm ~ (3.5-6) x 10^27 s consistent with previous detections.

    ↳ astro-ph.HEastro-ph.COhep-ph62 citations
25. 25*

    Complex Langevin dynamics for dynamical QCD at nonzero chemical potential: a comparison with multi-parameter reweighting

    Z. Fodor🇩🇪 · S. D. Katz🇭🇺 · D. Sexty🇩🇪 · C. Török🇭🇺

    We study lattice QCD at non-vanishing chemical potential using the complex Langevin equation. We compare the results with multi-parameter reweighting both from $\mu =0$ and phase quenched ensembles. We find a good agreement for lattice spacings below $\approx$0.15 fm. On coarser lattices the complex Langevin approach breaks down. Four flavors of staggered fermions are used on $N_t=4,6$ and 8 lattices. For one ensemble we also use two flavors to investigate the effects of rooting.

    ↳ hep-lathep-phPRD(2015)·85 citations
26. 26*

    Superconductivity at Any Temperature

    Mohamed M. Anber🇨🇭 · Yannis Burnier🇨🇭 · Eray Sabancilar🇨🇭 · Mikhail Shaposhnikov🇨🇭

    We construct a 2+1 dimensional model that sustains superconductivity at all temperatures. This is achieved by introducing a Chern Simons mixing term between two Abelian gauge fields A and Z. The superfluid is described by a complex scalar charged under Z, whereas a sufficiently strong magnetic field of A forces the superconducting condensate to form at all temperatures. In fact, at finite temperature, the theory exhibits Berezinsky-Kosterlitz-Thouless phase transition due to proliferation of topological vortices admitted by our construction. However, the critical temperature is proportional to the magnetic field of A, and thus, the phase transition can be postponed to high temperatures by increasing the strength of the magnetic field. This model can be a step towards realizing the long sought room temperature superconductivity.

    ↳ hep-thcond-mat.mes-hallcond-mat.supr-conhep-phPRD(2016)·5 citations
27. 27*

    Diamagnetic Vortices in Chern Simons Theory

    Mohamed M. Anber🇨🇭 · Yannis Burnier🇨🇭 · Eray Sabancilar🇨🇭 · Mikhail Shaposhnikov🇨🇭

    We find a new type of topological vortex solution in the $U(1{)}_Z\times U(1{)}_A$ Chern Simons gauge theory in the presence of a $U(1{)}_A$ magnetic field background. In this theory $U(1{)}_Z$ is broken spontaneously by the $U(1{)}_A$ magnetic field. These vortices exhibit long range interactions as they are charged under the unbroken $U(1{)}_A$. They deplete the $U(1{)}_A$ magnetic field near their core and also break both $C$ and $P$ symmetries. Understanding the nature of these vortices sheds light on the ground state structure of the superconductivity studied in [1]. We also study the Berezinsky-Kosterlitz-Thouless phase transition in this class of theories and point out that superconductivity can be achieved at high temperatures by increasing the $U(1{)}_A$ magnetic field.

    ↳ hep-thcond-mat.mes-hallcond-mat.supr-conhep-phPRD(2015)·4 citations
28. 28*

    Inflation in Supergravity with a Single Superfield

    Takahiro Terada🇯🇵

    Supergravity is a well-motivated theory beyond the standard model of particle physics, and a suitable arena to study high-energy physics at the early universe including inflation, whose observational evidences are growing more and more. Inflation in supergravity, however, cannot be easily described because of restrictions from supersymmetry (SUSY). The scalar potential has an exponential factor and a large negative term whereas a flat and positive potential is needed to realize inflation. The standard method to obtain such an inflationary scalar potential requires an additional superfield to the one containing inflaton. In this thesis, we propose and develop an alternative method which does not require the additional superfield and thus reduces the necessary degrees of freedom by half. That is, we study inflation in supergravity with only a single chiral superfield which contains inflaton. We accomplish it by introducing a higher dimensional term in the inflaton Kahler potential, which plays an important dual role: fixing the value of the scalar superpartner of the inflaton resulting in effective single field models, and ensuring the positivity of the inflaton potential at the large field region. Our proposal is not just particular models but rather a new framework to realize various inflationary models in supergravity. In particular, large field inflation in supergravity using one superfield without tuning has become possible for the first time. In our generic models, SUSY breaking at the inflationary scale by inflaton is not completely restored after inflation, so null results for SUSY search at the LHC are predicted for the simplest cases. Remarkably, however, it is possible with tuning to embed arbitrary positive semidefinite scalar potentials into supergravity preserving SUSY at the vacuum. Our discovery opens up an entirely new branch of model building of inflation in supergravity.

    ↳ hep-thgr-qchep-ph8 citations

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