Fri·Nov 25, 2016Friday·November 25, 2016

1. 01*

   The forward-backward asymmetry for massive bottom quarks at the $Z$ peak at next-to-next-to-leading order QCD

   Werner Bernreuther🇩🇪 · Long Chen🇩🇪 · Oliver Dekkers🇩🇪 · Thomas Gehrmann🇨🇭 · Dennis Heisler🇩🇪

   We compute the order ${\alpha }_s^2$ QCD corrections to the $b$-quark forward-backward asymmetry in $e^{+}{e}^{-}\to b\bar{b}$ collisions at the $Z$ boson resonance, taking the non-zero mass of the $b$ quark into account. We determine these corrections with respect to both the $b$-quark axis and the thrust axis definition of the asymmetry. We compute also the distributions of these axes with respect to the electron beam. If one neglects the flavor singlet contributions to the $b$-quark asymmetry, as was done in previous computations for massless $b$ quarks, then the second-order QCD corrections for $m_b\ne 0$ are smaller in magnitude than the corresponding corrections for $m_b=0$. Including the singlet contributions slightly increases the magnitude of the corrections. The massive ${\alpha }_s^2$ corrections to the $b$-quark forward-backward asymmetry slightly diminish the well-known tension between the bare $b$-quark asymmetry and the standard model fit from $2.9\sigma$ to $2.6\sigma$.

   hep-phhep-exJHEP(2017)·26 citations
2. 02*

   Calculable Cosmological CP Violation and Resonant Leptogenesis

   Avtandil Achelashvili🇬🇪 · Zurab Tavartkiladze🇬🇪

   Within the extension of MSSM by two right handed neutrinos, which masses are degenerate at tree level, we address the issue of leptogenesis. Investigating the quantum corrections in details, we show that the lepton asymmetry is induced at 1-loop level and decisive role is played by the tau lepton Yukawa coupling. On a concrete and predictive neutrino model, which enables to predict the CP violating $\delta$ phase and relate it to the cosmological CP asymmetry, we demonstrate that the needed amount of the baryon asymmetry is generated via the resonant leptogenesis.

   hep-phPRD(2017)·7 citations
3. 03*

   Cosmology in Mirror Twin Higgs and Neutrino Masses

   Zackaria Chacko🇺🇸 · Nathaniel Craig🇺🇸 · Patrick J. Fox🇺🇸 · Roni Harnik🇺🇸

   We explore a simple solution to the cosmological challenges of the original Mirror Twin Higgs (MTH) model that leads to interesting implications for experiment. We consider theories in which both the standard model and mirror neutrinos acquire masses through the familiar seesaw mechanism, but with a low right-handed neutrino mass scale of order a few GeV. In these $\nu$MTH models, the right-handed neutrinos leave the thermal bath while still relativistic. As the universe expands, these particles eventually become nonrelativistic, and come to dominate the energy density of the universe before decaying. Decays to standard model states are preferred, with the result that the visible sector is left at a higher temperature than the twin sector. Consequently the contribution of the twin sector to the radiation density in the early universe is suppressed, allowing the current bounds on this scenario to be satisfied. However, the energy density in twin radiation remains large enough to be discovered in future cosmic microwave background experiments. In addition, the twin neutrinos are significantly heavier than their standard model counterparts, resulting in a sizable contribution to the overall mass density in neutrinos that can be detected in upcoming experiments designed to probe the large scale structure of the universe.

   hep-phJHEP(2017)·140 citations
4. 04*

   Cosmological Signals of a Mirror Twin Higgs

   Nathaniel Craig🇺🇸 · Seth Koren🇺🇸 · Timothy Trott🇺🇸

   We investigate the cosmology of the minimal model of neutral naturalness, the mirror Twin Higgs. The softly-broken mirror symmetry relating the Standard Model to its twin counterpart leads to significant dark radiation in tension with BBN and CMB observations. We quantify this tension and illustrate how it can be mitigated in several simple scenarios that alter the relative energy densities of the two sectors while respecting the softly-broken mirror symmetry. In particular, we consider both the out-of-equilibrium decay of a new scalar as well as reheating in a toy model of twinned inflation, Twinflation. In both cases the dilution of energy density in the twin sector does not merely reconcile the existence of a mirror Twin Higgs with cosmological constraints, but predicts contributions to cosmological observables that may be probed in current and future CMB experiments. This raises the prospect of discovering evidence of neutral naturalness through cosmology rather than colliders.

   hep-phastro-ph.COJHEP(2017)·114 citations
5. 05*

   Can sea quark asymmetry shed light on the orbital angular momentum of the proton?

   Emanuele R. Nocera🇬🇧 · Elena Santopinto🇮🇹

   A striking prediction of several extensions of the constituent quark model, including the unquenched quark model, the pion cloud model and the chiral quark model, is a proportionality relationship between the quark sea asymmetry and the orbital angular momentum of the proton. We investigate to which extent a relationship of this kind is corroborated by the experiment, through a systematic comparison between expectations based on models and predictions obtained from a global analysis of hard-scattering data in perturbative Quantum Chromodynamics. We find that the data allows the angular momentum of the proton to be proportional to its sea asymmetry, though with a rather large range of the optimal values of the proportionality coefficient. Typical values do not enable us to discriminate among expectations based on different models. In order to make our comparison conclusive, the extrapolation uncertainties on the proportionality coefficient should be reduced, hopefully by means of accurate measurements in the region of small proton momentum fractions, where the data is currently lacking. Nevertheless, the unquenched quark model predicts that quarks account for a proton spin fraction much larger than that accepted by the conventional wisdom. We explicitly demonstrate that such a discrepancy can be reabsorbed in the unknown extrapolation region, without affecting the description of current data, by imposing the unquenched quark model expectation as a boundary condition in the analysis of the data itself. We delineate how the experimental programs at current and future facilities may shed light on the region of small momentum fractions.

   hep-ph5 citations
6. 06*

   QCD analysis of light charged Higgs production through polarized top quark decay in two various frames

   S. Mohammad Moosavi Nejad🇮🇷 · S. Abbaspour🇮🇷

   Light and heavy charged Higgs bosons are predicted by many models with an extended Higgs sector such as the two-Higgs-doublet model (2HDM). Searches for the charged Higgs bosons have been done by the ATLAS and the CMS experiments at the Large Hadron Collider (LHC) in proton-proton collision. However, a definitive search is a program that still has to be carried out so this belongs to the LHC experiments. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work we study the $\mathcal{O}({\alpha }_s)$ correction to the energy spectrum of the inclusive bottom-flavored mesons $(X_b)$ in polarized top quark decays into a light charged Higgs boson ($m_{H^{+}}<m_t$) and a massless bottom quark followed by the hadronization process $b\to X_b$ in the 2HDM, i.e. $t(\uparrow )\to H^{+}b\to H^{+}{X}_b+Jet$. This spin-dependent energy distribution is studied in two different helicity coordinate systems. This study could be considered as a new channel to search for the charged Higgs bosons. To present our phenomenological predictions, we restrict ourselves to the unexcluded regions of the MSSM $m_{H^{+}}-\tan \beta$ parameter space determined by the recent results of the CMS and the ATLAS collaborations.

   hep-phJHEP(2017)·5 citations
7. 07*

   General calculation of the cross section for dark matter annihilations into two photons

   Camilo Garcia-Cely🇧🇪 · Andres Rivera🇨🇴

   Assuming that the underlying model satisfies some general requirements such as renormalizability and CP conservation, we calculate the non-relativistic one-loop cross section for any self-conjugate dark matter particle annihilating into two photons. We accomplish this by carefully classifying all possible one-loop diagrams and, from them, reading off the dark matter interactions with the particles running in the loop. Our approach is general and leads to the same results found in the literature for popular dark matter candidates such as the neutralinos of the MSSM, minimal dark matter, inert Higgs and Kaluza-Klein dark matter.

   hep-phJCAP(2017)·19 citations
8. 08*

   Parity- and Time Reversal-Violating Pion Nucleon Couplings: Higher Order Chiral Matching Relations

   Chien-Yeah Seng🇨🇳 · Michael Ramsey-Musolf🇺🇸

   Parity- and time reversal-violating (PVTV) pion-nucleon couplings govern the magnitude of long-range contributions to nucleon and atomic electric dipole moments. When these couplings arise from chiral symmetry-breaking CP-violating operators, such as the QCD $\theta$-term or quark chromoelectric dipole moments, one may relate hadronic matrix elements entering the PVTV couplings to nucleon and pion mass shifts by exploiting the corresponding chiral transformation properties at leading order (LO) in the chiral expansion. We compute the higher-order contributions to the lowest order relations arising from chiral loops and next-to-next-to leading order (NNLO) operators. We find that for the QCD $\theta$-term the higher order contributions are analytic in the quark masses, while for the quark chromoelectric dipole moments and chiral symmetry-breaking four-quark operators, the matching relations also receive non-analytic corrections. Numerical estimates suggest that for the isoscalar PVTV pion-nucleon coupling, the higher order corrections may be as large as $\sim 20\%$, while for the isovector coupling, more substantial corrections are possible.

   hep-phnucl-thPRC(2017)·20 citations
9. 09*

   The LHC searches for heavy neutral Higgs bosons by jet substructure analysis

   Ning Chen🇨🇳

   The two-Higgs-doublet model contains extra Higgs bosons, with mass ranges spanning from several hundred GeV to about 1 TeV. We study the possible experimental searches for the neutral Higgs bosons of $A$ and $H$ at the future high-luminosity LHC runs. Besides of the conventional search modes that are inspired by the supersymmetric models, we discuss two search modes which were not quite addressed previously. They are the decay modes of $A\to hZ$ and $A/H\to t\bar{t}$. Thanks to the technique of tagging boosted objects of SM-like Higgs bosons and top quarks, we show the improved mass reaches for heavy neutral Higgs bosons with masses up to $\sim \mathcal{O}(1)\text{TeV}$. The modes proposed here are complementary to the conventional experimental searches motivated by the MSSM.

   hep-phhep-exInt.J.Mod.Phys.A(2016)·0 citations
10. 10*

    Accessing Generalized Parton Distributions in Exclusive Photoproduction of a $\gamma \rho$ Pair with a Large Invariant Mass

    R. Boussarie🇵🇱 · B. Pire🇫🇷 · L.Szymanowski🇵🇱 · S. Wallon🇫🇷

    We propose and study the photoproduction of a $\gamma \rho$ pair with a large invariant mass and a small transverse momentum of the final nucleon, as a way to access generalized parton distributions. In the kinematics of JLab 12-GeV, we demonstrate the feasibility of this measurement.

    hep-phhep-exnucl-exnucl-thAIP Conf.Proc.(2017)·0 citations
11. 11*

    Heavy Higgs boson production and decay into top quarks at the LHC

    Werner Bernreuther🇩🇪 · Peter Galler🇩🇪 · Clemens Mellein🇩🇪 · Zong-Guo Si🇨🇳 · Peter Uwer🇩🇪

    In this contribution we report on the calculation of the next-to-leading order (NLO) QCD corrections to the hadro-production of heavy neutral Higgs bosons and their decay into top-quark pairs within the type-II two-Higgs-doublet extension of the standard model (SM). We take into account the contributions from resonant Higgs boson production, the non-resonant SM $t\bar{t}$ background as well as the interference of these two contributions. The NLO corrections to the signal and interference contributions are calculated by applying the heavy top-quark mass ($m_t$) limit including an effective rescaling. In our NLO calculation the QCD-Higgs interference is evaluated in the resonance region that provides the dominant part of the heavy Higgs-boson contributions. Evaluating representative $CP$-conserving and $CP$-violating parameter scenarios within the two-Higgs-doublet model (2HDM) we present results for different distributions and, in addition, for observables that depend on the top-quark spin.

    hep-phPoS(2016)·0 citations
12. 12*

    Impact Factor for Exclusive Diffractive Dijet Production with NLO Accuracy

    R.Boussarie🇵🇱 · A. V. Grabovsky🇷🇺 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

    Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results.

    hep-phAIP Conf.Proc.(2017)·0 citations
13. 13*

    Influence of broken flavor and C and P symmetry on the quark propagator

    Axel Maas🇦🇹 · Walid Ahmed Mian🇦🇹

    Embedding QCD into the standard model breaks various symmetries of QCD explicitly, especially C and P. While these effects are usually perturbatively small, they can be amplified in extreme environments like merging neutron stars or by the interplay with new physics. To correctly treat these cases requires fully backcoupled calculations. To pave the way for later investigations of hadronic physics, we study the QCD quark propagator coupled to an explicit breaking. This substantially increases the tensor structure even for this simplest correlation function. To cope with the symmetry structure, and covering all possible quark masses, from the top quark mass to the chiral limit, we employ Dyson-Schwinger equations. While at weak breaking the qualitative effects have similar trends as in perturbation theory, even moderately strong breakings lead to qualitatively different effects, non-linearly amplified by the strong interactions.

    hep-phnucl-thEPJA(2017)·2 citations
14. 14*

    Effects of QCD bound states on dark matter relic abundance

    Seng Pei Liew🇯🇵 · Feng Luo🇯🇵

    We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by $\sim 30-100\%$ with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach $\sim 2.5$ TeV, even though the potential between the stop and antistop prior to forming a bound state is repulsive. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the BBN constraints and the abundance of a super-weakly interacting DM. The corrections for the bound-state effect when the exotic massive colored particles also carry electric charges, and the collider bounds are also discussed.

    hep-phJHEP(2017)·70 citations
15. 15*

    Double quarkonium production at high Feynman-$x$

    Sergey Koshkarev🇪🇪 · Stefan Groote🇪🇪

    In this paper we give estimates for the proton--proton cross sections into pairs of quarkonium states $J/\psi$, $\psi (2S)$, ${\rm Y}(1S)$ and ${\rm Y}(2S)$ at the scheduled AFTER@LHC energy of $115$GeV. The estimates are based on the intrinsic heavy flavor mechanism which is observable for high values of $x_F$, a range outside the dominance of single parton and double parton scattering.

    hep-phnucl-thNPB(2017)·6 citations
16. 16*

    Radiative distortion of kinematic edges in cascade decays

    Martin Beneke🇩🇪 · Laura Jenniches🇩🇪 · Alexander Mück🇩🇪 · Maria Ubiali🇬🇧

    Kinematic edges of cascade decays of new particles produced in high-energy collisions may provide important constraints on the involved particles' masses. For the exemplary case of gluino decay $\tilde{g}\to q\bar{q}\tilde{\chi }$ into a pair of quarks and a neutralino through a squark resonance, we study the hadronic invariant mass distribution in the vicinity of the kinematic edge. We perform a next-to-leading order calculation in the strong coupling ${\alpha }_s$ and the ratio of squark width and squark mass \Gamma_\tilde{q}/m_\tilde{q}, based on a systematic expansion in \Gamma_\tilde{q}/m_\tilde{q}. The separation into hard, collinear and soft contributions elucidates the process dependent and universal features of distributions in the edge region, represented by on-shell decay matrix elements, universal jet functions and a soft function that depends on the resonance propagator and soft Wilson lines.

    hep-phPLB(2017)·2 citations
17. 17*

    Phenomenology of Left-Right Models in the quark sector

    Luiz Vale Silva🇫🇷

    A natural avenue to extend the Standard Model (SM) is to embed it into a more symmetric framework. Here, I focus in Left-Right (LR) Models, which treat left- and right-handed chiralities on equal footing. Important information about the structure of LR Models comes from meson-mixing observables. Due to the impact of the new contributions to these processes, I consider the calculation of the short-distance QCD effects correcting the LR Model contributions to meson-mixing observables at the Next-to-Leading Order. I then revisit the phenomenology of a simple realization of LR Models, containing doublet scalars, and combine in a global fit electroweak precision observables, direct searches of the new gauge bosons and meson oscillation observables, a task performed within the CKMfitter statistical framework. Finally, I also cover a different issue, namely the modeling of theoretical uncertainties, a class of uncertainties specially important for flavour physics. Different frequentist schemes are compared, and their differences are illustrated with flavour-oriented examples.

    hep-ph5 citations
18. 18*

    Semiexclusive production of $J/\psi$ mesons in proton-proton collisions with electromagnetic and diffractive dissociation of one of the protons

    Anna Cisek🇵🇱 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    We calculate the cross sections for both electromagnetic and diffractive dissociation of protons for semiexclusive production of $J/\psi$ mesons in proton-proton collisions at the LHC. Several differential distributions in missing mass ($M_X$), or single-particle variables related exclusively to the $J/\psi$ meson are calculated for $\sqrt{s}$ = 7 TeV as an example. The cross sections and distributions are compared to the cross section of the purely exclusive reaction $pp\to ppJ/\psi$. We show the corresponding ratio as a function of $J/\psi$ meson rapidity. We compare the distributions for purely electromagnetic and purely diffractive proton excitations/dissociation. We predict cross sections for electromagnetic and diffractive excitations of similar order of magnitude.

    hep-phPLB(2017)·17 citations
19. 19*

    EW corrections to $t\bar{t}$ distributions: the photon PDF effect

    Ioannis Tsinikos🇧🇪

    In this proceeding we present the impact of the EW corrections on $t\bar{t}$ distributions focusing on the effect of the photon PDF. We use the {\sc NNPDF2.3QED} and {\sc CT14QED} PDF sets, which include the photon PDF. We discuss a detailed comparison between the results obtained from these two PDF sets at NLO QCD+EW accuracy for 13 TeV, focusing on the top-quark $p_T$ and the top-quark pair rapidity. We point out the differences between these two PDF sets and we show that the rapidity of the top-quark pair can be used in order to constrain the photon PDF predicted by the {\sc NNPDF2.3QED} set.

    hep-ph4 citations
20. 20*

    Towards NNLO accuracy for ${\epsilon }^{\prime }/\epsilon$

    M Cerdà-Sevilla🇬🇧 · M Gorbahn🇬🇧 · S Jäger🇬🇧 · A Kokulu🇬🇧

    The quantity ${\epsilon }^{\prime }/\epsilon$ measures direct CP violation in Kaon decays. Recent SM predictions show a $2.9\sigma$ tension with data, with the theoretical uncertainty dominating. As rapid progress on the lattice is bringing nonperturbative long-distance effects under control, a more precise knowledge of short-distance contributions is needed. We describe the first NNLO results for ${\epsilon }^{\prime }/\epsilon$ and discuss future prospects, as well as issues of scheme dependence and the separation of perturbative and nonperturbative effects. Finally we also comment on the solution of the renormalisation-group evolution in one of the talks at this conference and present the correct solution.

    hep-phJ.Phys.Conf.Ser.(2017)·34 citations
21. 21*

    Recent progress on CP violation in $K\to \pi \pi$ decays in the SM and a supersymmetric solution

    Teppei Kitahara🇩🇪 · Ulrich Nierste🇩🇪 · Paul Tremper🇩🇪

    Using the recent first lattice results of the RBC-UKQCD collaboration for $K\to \pi \pi$ decays, we perform a phenomenological analysis of ${ϵ}_K^{\prime }/{ϵ}_K$ and find a discrepancy between SM prediction and experiments by $\sim 3\sigma$. We discuss an explanation by new physics. The well-understood value of ${ϵ}_K$, which quantifies indirect $CP$ violation, however, typically prevents large new physics contributions to ${ϵ}_K^{\prime }/{ϵ}_K$. In this talk, we show a solution of the ${ϵ}_K^{\prime }/{ϵ}_K$ discrepancy in the Minimal Supersymmetric Standard Model with squark masses above 3 TeV without fine-tuning of $CP$ phases. In this solution, the Trojan penguin diagram gives large isospin-breaking contributions which enhance ${ϵ}_K^{\prime }$, while the contribution to ${ϵ}_K$ is suppressed thanks to the Majorana nature of gluinos.

    hep-phJ.Phys.Conf.Ser.(2017)·1 citation
22. 22*

    Mu-tau reflection symmetry with a texture-zero

    C. C. Nishi🇧🇷 · B. L. Sánchez-Vega🇧🇷

    The $\mu \tau$-reflection symmetry is a simple symmetry capable of predicting all the unknown CP phases of the lepton sector and the atmospheric angle but too simple to predict the absolute neutrino mass scale or the mass ordering. We show that by combining it with a discrete abelian symmetry in a nontrivial way we can additionally enforce a texture-zero and obtain a highly predictive scenario where the lightest neutrino mass is fixed to be in the few meV range for two normal ordering (NO) solutions or in the tens of meV in one inverted ordering (IO) solution. The rate for neutrinoless double beta decay is predicted to be negligible for NO or have effective mass $m_{\beta \beta }\approx 14\text{ – }29\mathrm{meV}$ for IO, right in the region to be probed in future experiments.

    hep-phJHEP(2017)·36 citations
23. 23*

    Bose-Einstein-condensed scalar field dark matter and the gravitational wave background from inflation: new cosmological constraints and its detectability by LIGO

    Bohua Li🇺🇸 · Paul R. Shapiro🇺🇸 · Tanja Rindler-Daller🇺🇸

    We consider an alternative cold dark matter candidate, ultralight bosons ($m>10^{-22}$eV) described by a complex scalar field (SFDM) with global U(1) symmetry, with comoving particle number density conserved after particle production during standard reheating. We allow for repulsive self-interaction. In a Lambda-SFDM universe, SFDM starts relativistic, evolving from stiff (w=1) to radiation-like (w=1/3), becoming nonrelativistic (w=0) at late times. Thus, a stiff-SFDM-dominated era precedes the familiar radiation-dominated era. SFDM particle mass $m$ and quartic self-interaction strength \lambda, are therefore constrained by cosmological observables, N_{eff}, the effective number of neutrino species during BBN, and z_{eq}, the matter-radiation equality redshift. Since the stochastic gravitational wave background (SGWB) from inflation is amplified during the stiff-SFDM-dominated era, it can also contribute a radiationlike component large enough to affect these observables. Remarkably, this amplification makes this SGWB detectable by current GW experiments, e.g., aLIGO/Virgo and LISA, for Lambda-SFDM models satisfying cosmological constraints, for a range of reheat temperatures T_{re} and currently allowed values of tensor-to-scalar ratio $r$. For given r and $\lambda /(m{c}^2{)}^2$, the marginally-allowed Lambda-SFDM model for each T_{re} has the smallest m that satisfies cosmological constraints. For example, for marginally-allowed models with r=0.01 and $\lambda /(m{c}^2{)}^2=10^{-18}$eV${}^{-1}$cm${}^3$, null detection by the aLIGO O1 run excludes 8.75*10^3<T_{re} (GeV)<1.7*10^5 at 95% confidence, demonstrating that GW experiments already place a new kind of cosmological constraint on SFDM. A wider parameter range should be accessible to aLIGO/Virgo O5, with potential to detect this signature of Lambda-SFDM. For this same illustrative family, 3-sigma detection is predicted for 600<T_{re} (GeV)<10^7.

    ↳ astro-ph.COgr-qchep-phPRD(2017)·87 citations
24. 24*

    An effective description of dark matter and dark energy in the mildly non-linear regime

    Matthew Lewandowski🇫🇷 · Azadeh Maleknejad🇮🇷 · Leonardo Senatore🇺🇸

    In the next few years, we are going to probe the low-redshift universe with unprecedented accuracy. Among the various fruits that this will bear, it will greatly improve our knowledge of the dynamics of dark energy, though for this there is a strong theoretical preference for a cosmological constant. We assume that dark energy is described by the so-called Effective Field Theory of Dark Energy, which assumes that dark energy is the Goldstone boson of time translations. Such a formalism makes it easy to ensure that our signatures are consistent with well-established principles of physics. Since most of the information resides at high wavenumbers, it is important to be able to make predictions at the highest wavenumber that is possible. The Effective Field Theory of Large-Scale Structure (EFTofLSS) is a theoretical framework that has allowed us to make accurate predictions in the mildly non-linear regime. In this paper, we derive the non-linear equations that extend the EFTofLSS to include the effect of dark energy both on the matter fields and on the biased tracers. For the specific case of clustering quintessence, we then perturbatively solve to cubic order the resulting non-linear equations and construct the one-loop power spectrum of the total density contrast.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2017)·59 citations
25. 25*

    Astrophysical Neutrino Production Diagnostics with the Glashow Resonance

    Daniel Biehl🇩🇪 · Anatoli Fedynitch🇩🇪 · Andrea Palladino🇮🇹 · Tom J. Weiler🇺🇸 · Walter Winter🇩🇪

    We study the Glashow resonance ${\bar{\nu }}_e+e^{-}\to W^{-}\to$ hadrons at 6.3 PeV as diagnostic of the production processes of ultra-high energy neutrinos. The focus lies on describing the physics of neutrino production from pion decay as accurate as possible by including the kinematics of weak decays and Monte Carlo simulations of pp and p$\gamma$ interactions. We discuss optically thick (to photohadronic interactions) sources, sources of cosmic ray nuclei and muon damped sources. Even in the proposed upgrade IceCube-Gen2, a discrimination of scenarios such as pp versus p$\gamma$ is extremely challenging under realistic assumptions. Nonetheless, the Glashow resonance can serve as a smoking gun signature of neutrino production from photohadronic (A$\gamma$) interactions of heavier nuclei, as the expected Glashow event rate exceeds that of pp interactions. We finally quantify the exposures for which the non-observation of Glashow events exerts pressure on certain scenarios.

    ↳ astro-ph.HEhep-phJCAP(2017)·56 citations
26. 26*

    Renormalization Group Flow, Stability, and Bulk Viscosity in a Large N Thermal QCD Model

    Keshav Dasgupta🇨🇦 · Maxim Emelin🇨🇦 · Charles Gale🇨🇦 · Michael Richard🇨🇦

    The ultraviolet completion of a large N QCD model requires introducing new degrees of freedom at certain scale so that the UV behavior may become asymptotically conformal with no Landau poles and no UV divergences of Wilson loops. These UV degrees of freedom are represented by certain anti-branes arranged on the blown-up sphere of a warped resolved conifold in a way that they are separated from the other set of branes that control the IR behavior of the theory. This separation of the branes and the anti-branes creates instability in the theory. Further complications arise from the curvature of the ambient space. We show that, despite these analytical hurdles, stability may still be achieved by switching on appropriate world-volume fluxes on the branes. The UV degrees of freedom, on the other hand, modify the RG flow in the model. We discuss this in details by evaluating the flow from IR confining to UV conformal. Finally we lay down a calculational scheme to study bulk viscosity which, in turn, would signal the inherent non-conformality in this model.

    ↳ hep-thhep-phnucl-thPRD(2017)·3 citations
27. 27*

    Equation of state dependence of directed flow in a microscopic transport model

    Yasushi Nara🇯🇵 · Harri Niemi🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪

    We study the sensitivities of the directed flow in Au+Au collisions on the equation of state (EoS), employing the transport theoretical model JAM. The EoS is modified by introducing a new collision term in order to control the pressure of a system by appropriately selecting an azimuthal angle in two-body collisions according to a given EoS. It is shown that this approach is an efficient method to modify the EoS in a transport model. The beam energy dependence of the directed flow of protons is examined with two different EoS, a first-order phase transition and crossover. It is found that our approach yields quite similar results as hydrodynamical predictions on the beam energy dependence of the directed flow; Transport theory predicts a minimum in the excitation function of the slope of proton directed flow and does indeed yield negative directed flow, if the EoS with a first-order phase transition is employed. Our result strongly suggests that the highest sensitivity for the critical point can be seen in the beam energy range of $4.7\le \text{srtNN}\le 11.5$ GeV.

    ↳ nucl-thhep-phnucl-exPLB(2017)·56 citations
28. 28*

    CMB spectral distortions as solutions to the Boltzmann equations

    Atsuhisa Ota🇯🇵

    Distortions to the cosmic microwave background~(CMB) blackbody spectrum are calculated in the framework of cosmological perturbation theory. The second order Boltzmann equation is explicitly solved, with the spectral $y$ distortion and the frequency independent second order temperature perturbation. We also solve higher order Boltzmann equations systematically and find new type spectral distortions in the low energy limit of electrons. As an example, we concretely construct a solution to the cubic order Boltzmann equation and show that it can be characterized by three parameters: a cubic order temperature perturbation and two different types of cubic order spectral distortions. A new linear Sunyaev-Zel'dovich effect whose frequency dependence is different from the usual $y$ distortion is also discussed in the presence of the next-to-leading order Kompaneets terms, and we show that higher order spectral distortions are also generated as a result of the diffusion process in a framework of the higher order cosmological perturbation theory. We also comment that generation of the spectral $\mu$ distortion cannot be explained in this framework even at second order.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2017)·13 citations
29. 29*

    High and low mass Axion Haloscopes at UWA

    Ben T. McAllister🇦🇺 · Stephen R. Parker🇦🇺 · Eugene N. Ivanov🇦🇺 · Michael E. Tobar🇦🇺

    We consider the design of a haloscope experiment (ORGAN) to probe for axions at 26.6 GHz. The motivation for this search is to perform the first direct test of a result which claims a possible axion signal at this frequency. There are many technical issues and optimisations that must be considered in the design of a high mass axion haloscope. We discuss the current status of the ORGAN experiment, as well as its future. We also discuss low mass axion haloscopes employing lumped 3D LC resonators.

    ↳ hep-exhep-phphysics.ins-det2 citations
30. 30*

    Confinement in a three-dimensional Yang-Mills theory

    Marco Frasca🇮🇹

    We show that, starting from known exact classical solutions of the Yang-Mills theory in three dimensions, the string tension is obtained and the potential is consistent with a marginally confining theory. The potential we obtain agrees fairly well with preceding findings in literature but here we derive it analytically from the theory without further assumptions. The string tension is in strict agreement with lattice results and the well-known theoretical result by Karabali-Kim-Nair analysis. Classical solutions depend on a dimensionless numerical factor arising from integration. This factor enters into the determination of the spectrum and has been arbitrarily introduced in some theoretical models. We derive it directly from the solutions of the theory and is now fully justified. The agreement obtained with the lattice results for the ground state of the theory is well below 1% at any value of the degree of the group.

    ↳ hep-thhep-lathep-phEPJC(2017)·19 citations
31. 31*

    Evidence of the mixed phase formation in nucleus-nucleus collisions

    V. V. Sagun🇺🇦 · K. A. Bugaev🇺🇦 · A. I. Ivanytskyi🇺🇦 · D. R. Oliinychenko🇺🇦

    Searchers for various irregularities in the behavior of thermodynamic quantities at chemical freeze-out (CFO) are rather important in a view of experimental studies of quark-gluon plasma (QGP). Using the multicomponent hadron resonance gas model (HRGM), developed in (Sagun, 2014; Bugaev et al., 2015), we performed a high-quality fit of 111 hadronic ratios measured for 14 values of the center of mass collision energies between 2.7 GeV and 200 GeV with the overall fit quality ${\chi }^2/dof\simeq 0.95$. In addition to previously reported singularities (Bugaev et al., 2015) at CFO we found that the hadron yield ratios $\frac{\Lambda }{p}$, $\frac{K^{+}}{p}$, $\frac{K^{+}}{\Lambda }$, $\frac{{\Omega }^{-}}{p}$ and $\frac{{\Xi }^{-}}{p}$ measured in central nuclear collisions demonstrate a significant change of slope in the same range of center of mass collision energy $\sqrt{s_{NN}}=4.3-4.9$ GeV (Bugaev et al., 2015). This change of slopes is accompanied by a dramatic increase of resonance decays at CFO. Also at CFO the trace anomaly and baryonic density demonstrate the pronounced peaks at the collision energy $\sqrt{s_{NN}}=4.9$ GeV. We argue that all these and previously found irregularities provide an evidence for the QGP formation in nuclear collisions at about $\sqrt{s_{NN}}=4.9$ GeV.

    ↳ nucl-thhep-phWDS`16 Proceedings of Contributed Papers …·0 citations
32. 32*

    The quantum vacuum in electromagnetic fields: From the Heisenberg-Euler effective action to vacuum birefringence

    Felix Karbstein🇩🇪

    The focus of these lectures is on the quantum vacuum subjected to classical electromagnetic fields. To this end we explicitly derive the renowned Heisenberg-Euler effective action in constant electromagnetic fields in a rather pedagogical and easy to conceive way. As an application, we use it to study vacuum birefringence constituting one of the most promising optical signatures of quantum vacuum nonlinearity.

    ↳ hep-thhep-ph22 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.