Mon·Oct 1, 2018Monday·October 1, 2018

1. 01*

   Jet shape modifications in holographic dijet systems

   Jasmine Brewer🇺🇸 · Andrey Sadofyev🇺🇸 · Wilke van der Schee🇺🇸

   We present a coherent model that combines jet production from perturbative QCD with strongly-coupled jet-medium interactions described in holography. We use this model to study the modification of an ensemble of jets upon propagation through a quark-gluon plasma resembling central heavy ion collisions. Here the modification of the dijet asymmetry depends strongly on the subleading jet width, which can therefore be an important observable for studying jet-medium interactions. We furthermore show that the modification of the shape of the leading jet is relatively insensitive to the dijet asymmetry, whereas the subleading jet shape modification is much larger for more imbalanced dijets. Finally, we compare the results of our holographic model to a recent CMS measurement.

   hep-phhep-thnucl-exnucl-thPLB(2021)·23 citations
2. 02*

   Diffractive patterns in deep-inelastic scattering and parton genealogy

   Stéphane Munier🇫🇷

   We report on our recent observation that the occurrence of diffractive patterns in the scattering of electrons off nuclei obeys the same law as the fluctuations of the height of genealogical trees in branching diffusion processes.

   hep-phEPJ Web Conf.(2018)·2 citations
3. 03*

   Solutions to Axion Electrodynamics in Various Geometries

   J. L. Ouellet🇺🇸 · Z. Bogorad🇺🇸

   Recently there has been a surge of new experimental proposals to search for ultra-light axion dark matter with axion mass, $m_a\lesssim 1\mu$eV. Many of these proposals search for small oscillating magnetic fields induced in or around a large static magnetic field. Lately, there has been interest in alternate detection schemes which search for oscillating electric fields in a similar setup. In this paper, we explicitly solve Maxwell's equations in a simplified geometry and demonstrate that in this mass range, the axion induced electric fields are heavily suppressed by boundary conditions. Unfortunately, experimentally measuring axion induced electric fields is not feasible in this mass regime using the currently proposed setups with static primary fields. We show that at larger axion masses, induced electric fields are not suppressed, but boundary effects may still be relevant for an experiment's sensitivity. We then make a general argument about a generic detector configuration with a static magnetic field to show that the electric fields are always suppressed in the limit of large wavelength.

   hep-phhep-exPRD(2019)·79 citations
4. 04*

   Coulomb correction to the spectral bremsstrahlung rate in the quantum Migdal theory of the Landau-Pomeranchuk effect

   O Voskresenskaya🇷🇺

   High-energy Coulomb corrections (CCs) to some quantities of the quantum Migdal theory of the Landau-Pomeranchuk-Migdal (LPM) effect are obtained analytically and numerically for the regimes of small and strong LPM suppression on the basis of a refined Moliere multiple scattering theory. Numerical calculations are presented in the ranges of the nuclear charge number Z of a scatterer from 6 to 92 and the expansion parameter B of Moliere from 4.5 to 8.5. It is shown that the relative CC to the spectral bremsstrahlung rate can reach a value of the order of -19% in the ranges considered and must be borne in mind, e.g., in the Monte-Carlo analysis of electromagnetic cascade LPM showers in extremely high-energy region.

   hep-ph0 citations
5. 05*

   Form factors for pions couplings to constituent quarks under weak magnetic field

   Fabio L. Braghin🇧🇷 · Willian F. de Sousa🇧🇷

   By considering a one loop background field method for a nonperturbative one gluon exchange between quarks, leading electromagnetic form factors of pion couplings to constituent quarks are derived by means of from a large quark and gluon effective masses expansion. With this calculation the leading anisotropic corrections induced by a weak magnetic field for the pion-constituent quark form factors are obtained. Besides that, few effective couplings which emerge only due to the weak magnetic field that break chiral and isospin symmetry are also found. Numerical estimations for these magnetic field corrections are presented for two different nonperturbative gluon propagators. All of these corrections are ultraviolet finite and their relative values are found to be of order of $(e{B}_0/{M^{\ast }}^2{)}^n$ being $n=1$ for the vector and axial pion couplings and $n=2$ for the pseudoscalar and scalar ones. The corresponding anisotropic corrections to the Strong averaged quadratic radii in the plane perpendicular to the magnetic field are also calculated as functions of the quark effective mass.

   hep-phnucl-thJ.Phys.G(2020)·9 citations
6. 06*

   Limits on Electroweak Instanton-Induced Processes with Multiple Boson Production

   Andreas Ringwald🇩🇪 · Kazuki Sakurai🇵🇱 · Bryan R. Webber🇬🇧

   Recently, the CMS collaboration has reported their search for electroweak instanton-like processes with anomalous $B+L$ violation assuming multi-fermion but zero-boson final states. On the other hand, many theoretical studies suggest that anomalous $B+L$ processes may have an observably large production rate only if their final state contains a large number of electroweak gauge bosons. In this paper, we compare collider signatures of zero- and multi-boson events of anomalous $B+L$ violation at the LHC and derive an upper limit on the cross-section for the multi-boson process by recasting the CMS analysis.

   hep-phJHEP(2018)·11 citations
7. 07*

   Higgs production in association with bottom quark pair at LHC

   Wen-Tao Huang🇨🇳 · Hong-Lei Li🇨🇳 · Shi-Yuan Li🇨🇳 · Peng-Cheng Lu🇨🇳 · Zong-Guo Si🇨🇳 · Ying Wang🇨🇳 · Zhong-Juan Yang🇨🇳

   The direct observation of the Yukawa interaction related to Standard Model Higgs and the bottom quark is obtained from the $h\to b\bar{b}$ process recently. The b-tagging becomes an important tool to search for new heavy resonance production at LHC. We use the b-tagging method to investigate the neutral Higgs production in association with a bottom quark pair, and perform the detector simulation for the signal process with the Higgs decaying into $b\bar{b}$ or ${\tau }^{+}{\tau }^{-}$ together with the dominant backgrounds. Our results show that $b\bar{b}b\bar{b}$ and $b\bar{b}{\tau }^{+}{\tau }^{-}$ processes will play an important role to search for the exotic heavy Higgs production at LHC and future hadron colliders.

   hep-phInt.J.Mod.Phys.A(2019)·1 citation
8. 08*

   Triangle singularity in ${\tau }^{-}\to {\nu }_{\tau }{\pi }^{-}{f}_0(980)$ ($a_0(980)$) decays

   L. R. Dai🇨🇳 · Q. X. Yu🇨🇳 · E. Oset🇪🇸

   We study the triangle mechanism for the decay ${\tau }^{-}\to {\nu }_{\tau }{\pi }^{-}{f}_0(980)$, with the $f_0(980)$ decaying into ${\pi }^{+}{\pi }^{-}$. This process is initiated by ${\tau }^{-}\to {\nu }_{\tau }{K}^{\ast 0}{K}^{-}$ followed by the $K^{\ast 0}$ decay into ${\pi }^{-}{K}^{+}$, then the $K^{-}{K}^{+}$ produce the $f_0(980)$ through a triangle loop containing $K^{\ast }{K}^{+}{K}^{-}$ which develops a singularity around $1420$~MeV in the $\pi f_0(980)$ invariant mass. We find a narrow peak in the ${\pi }^{+}{\pi }^{-}$ invariant mass distribution, which originates from the $f_0(980)$ amplitude. Similarly, we also study the triangle mechanism for the decay $\tau \to \nu {\pi }^{-}{a}_0(980)$, with the $a_0(980)$ decaying into ${\pi }^0\eta$. The final branching ratios for ${\pi }^{-}{f}_0(980)$ and ${\pi }^{-}{a}_0(980)$ are of the order of $4\times 10^{-4}$ and $7\times 10^{-5}$, respectively, which are within present measurable range. Experimental verification of these predictions will shed light on the nature of the scalar mesons and on the origin for the "$a_1(1420)$" peak observed in other reactions.

   hep-phPRD(2019)·32 citations
9. 09*

   A light dimuon resonance in B decays?

   Filippo Sala🇩🇪

   The observed deviations from the Standard Model in several b -> s mu mu processes can be explained in terms of a new vector boson produced on-shell in B meson decays. A mass of 2.5-3 GeV and a total width of 10-20% allow to hide the associated dimuon bump in the poorly known charmonium region, and the large invisible decay width can be interpreted in terms of Dark Matter. This proposal predicts a contribution to the muon anomalous magnetic moment, that could explain the long-standing tension with the Standard Model. It also predicts sizeable invisible B decays and a peculiar q^2-dependence of the lepton flavor universality ratios R_K and R_K* , that could be tested at the LHCb and Belle-II. This proceeding is based on arXiv:1704.06188, and slightly extends it with comments about Dark Matter.

   hep-phNucl.Part.Phys.Proc.(2018)·5 citations
10. 10*

    Supersymmetry and LHC Missing Energy Signals

    Marcela Carena🇺🇸 · James Osborne🇺🇸 · Nausheen R. Shah🇺🇸 · Carlos E. M. Wagner🇺🇸

    Current analyses of the LHC data put stringent bounds on strongly interacting supersymmetric particles, restricting the masses of squarks and gluinos to be above the TeV scale. However, the supersymmetric electroweak sector is poorly constrained. In this article we explore the consistency of possible LHC missing energy signals with the broader phenomenological structure of the electroweak sector in low energy supersymmetry models. As an example, we focus on the newly developed Recursive Jigsaw Reconstruction analysis by ATLAS, which reports interesting event excesses in channels containing di-lepton and tri-lepton final states plus missing energy. We show that it is not difficult to obtain compatibility of these LHC data with the observed dark matter relic density, the bounds from dark matter direct detection experiments, and the measured anomalous magnetic moment of the muon. We provide analytical expressions which can be used to understand the range of gaugino masses, the value of the Higgsino mass parameter, the heavy Higgs spectrum, the ratio of the Higgs vacuum expectation values $\tan \beta$, and the slepton spectrum obtained in our numerical analysis of these observables.

    hep-phhep-exPRD(2018)·31 citations
11. 11*

    Heavy quarkonia: the beauty and the beasts

    George Rupp🇵🇹 · Eef van Beveren🇵🇹

    New enhancements in the charmonium and bottomonium spectra observed since 2003 are very briefly reviewed. Special attention is paid to ${\chi }_{c1}(3872)$ (formerly $X(3872)$) owing to its remarkable proximity to the ${\bar{D}}^{\star 0}{D}^0$ threshold, which allows modelling as a quasibound axial-vector $c\bar{c}$ state with a large ${\bar{D}}^{\star 0}{D}^0$ admixture. In contrast, the interpretation of many other charmonium-like and bottomonium-like states is still very controversial and some may not even correspond to genuine resonances. Accordingly, several entries in the PDG tables have been wildly changing over the years. Three representative states are reviewed here as non-resonant enhancements due to threshold effects, viz. $\psi (4260)$, $\psi (4660)$, and ${\rm Y}(10580)$.

    hep-phhep-exJ.Phys.Conf.Ser.(2019)·1 citation
12. 12*

    Detecting CP Violation in the Presence of Non-Standard Neutrino Interactions

    Jeffrey M. Hyde🇺🇸

    New physics beyond the Standard Model could appear at long baseline oscillation experiments as non-standard interactions (NSI) between neutrinos and matter. If so, determination of the CP-violating phase ${\delta }_{13}$ is ambiguous due to interference with additional complex phases. I'll present my work using both numerical solutions and a perturbative approach to study oscillation probabilities in the presence of NSI. I'll show how the CP phase degeneracies are visualized on biprobability plots, and the extent to which the energy spectrum for a given baseline length can help resolve them. In particular, this shows how the broad range of energies at DUNE would help distinguish between maximal, standard CP violation and the absence of CP violation with large ${ϵ}_{e\tau }$.

    hep-ph0 citations
13. 13*

    Gravitational waves from conformal symmetry breaking

    Tomislav Prokopec🇳🇱 · Jonas Rezacek🇳🇱 · Bogumila Swiezewska🇳🇱

    We consider the electroweak phase transition in the conformal extension of the standard model known as SU(2)cSM. Apart from the standard model particles, this model contains an additional scalar and gauge field that are both charged under the hidden SU(2)${}_X$. This model generically exhibits a very strong phase transition that proceeds after a large amount of supercooling. We estimate the gravitational wave spectrum produced in this model and show that its amplitude and frequency fall within the observational window of LISA. We also discuss potential pitfalls and relevant points of improvement required to attain reliable estimates of the gravitational wave production in this - as well as in more general - class of models. In order to improve perturbativity during the early stages of transition that ends with bubble nucleation, we solve a thermal gap equation in the scalar sector inspired by the 2PI effective action formalism.

    hep-phastro-ph.COhep-thJCAP(2019)·113 citations
14. 14*

    Consistency of Higgsplosion in Localizable QFT

    Valentin V. Khoze🇬🇧 · Michael Spannowsky🇬🇧

    We show that large n-particle production rates derived in the semiclassical Higgsplosion limit of scalar field theoretical models with spontaneous symmetry breaking, are consistent with general principles of localizable quantum field theory. The strict localizability criterium of Jaffe defines quantum fields as operator-valued distributions acting on test functions that are localized in finite regions of space-time. The requirement of finite support of test functions in space-time ensures the causality property of QFT. The corresponding localizable fields need not be tempered distributions, and they fit well into the framework of local quantum field theory.

    hep-phhep-thPLB(2019)·15 citations
15. 15*

    Machine Learning for New Physics Searches

    Raffaele Tito D'Agnolo🇺🇸

    This is the summary of a talk given at CIPANP 2018. I briefly introduce neural networks and then discuss a new technique for model-independent new physics searches in background-dominated datasets.

    hep-ph0 citations
16. 16*

    Two-pion contribution to hadronic vacuum polarization

    Gilberto Colangelo🇨🇭 · Martin Hoferichter🇺🇸 · Peter Stoffer🇺🇸

    We present a detailed analysis of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ data up to $\sqrt{s}=1\text{GeV}$ in the framework of dispersion relations. Starting from a family of $\pi \pi$ $P$-wave phase shifts, as derived from a previous Roy-equation analysis of $\pi \pi$ scattering, we write down an extended Omnès representation of the pion vector form factor in terms of a few free parameters and study to which extent the modern high-statistics data sets can be described by the resulting fit function that follows from general principles of QCD. We find that statistically acceptable fits do become possible as soon as potential uncertainties in the energy calibration are taken into account, providing a strong cross check on the internal consistency of the data sets, but preferring a mass of the $\omega$ meson significantly lower than the current PDG average. In addition to a complete treatment of statistical and systematic errors propagated from the data, we perform a comprehensive analysis of the systematic errors in the dispersive representation and derive the consequences for the two-pion contribution to hadronic vacuum polarization. In a global fit to both time- and space-like data sets we find $a_{\mu }^{\pi \pi }{|}_{\le 1\text{GeV}}=495.0(1.5)(2.1)\times 10^{-10}$ and $a_{\mu }^{\pi \pi }{|}_{\le 0.63\text{GeV}}=132.8(0.4)(1.0)\times 10^{-10}$. While the constraints are thus most stringent for low energies, we obtain uncertainty estimates throughout the whole energy range that should prove valuable in corroborating the corresponding contribution to the anomalous magnetic moment of the muon. As side products, we obtain improved constraints on the $\pi \pi$ $P$-wave, valuable input for future global analyses of low-energy $\pi \pi$ scattering, as well as a determination of the pion charge radius, $⟨r_{\pi }^2⟩=0.429(1)(4){\text{fm}}^2$.

    hep-phhep-exhep-latnucl-thJHEP(2019)·606 citations
17. 17*

    Constraining neutrino mass with tomographic weak lensing one-point probability distribution function and power spectrum

    Jia Liu🇺🇸 · Mathew S. Madhavacheril (Princeton)🇺🇸

    We study the constraints on neutrino mass sum (M_nu) from the one-point probability distribution function (PDF) and power spectrum of weak lensing measurements for an LSST-like survey, using the MassiveNuS simulations. The PDF provides access to non-Gaussian information beyond the power spectrum. It is particularly sensitive to nonlinear growth on small scales, where massive neutrinos also have the largest effect. We find that tomography helps improve the constraint on M_nu by 14% and 32% for the power spectrum and the PDF, respectively, compared to a single redshift bin. The PDF alone outperforms the power spectrum in constraining M_nu. When the two statistics are combined, the constraint is further tightened by 35%. We conclude that weak lensing PDF is complementary to the power spectrum and has the potential to become a powerful tool for constraining neutrino mass.

    ↳ astro-ph.COhep-phphysics.data-anPRD(2019)·88 citations
18. 18*

    Virtual and Thermal Schwinger Processes

    Patrick Draper🇺🇸

    Electric flux may be screened by pair nucleation of heavy charges, a process that has a simple description in terms of a worldline instanton. When flux is wrapped around a small compact spatial dimension, worldline instantons still induce flux dissipation, but the leading process does not create real charged pairs. Instead, dissipation can be described in effective field theory as the production of long-wavelength scalar quanta via parametric resonance. The rate is computed semiclassically, and comments are made on the related problem of pair creation at finite temperature, for which differing results appear in the literature. Flux dissipation and the weak gravity conjecture together imply that the proper distance in field space a homogeneous axion field can traverse is bounded.

    ↳ hep-thhep-phPRD(2018)·18 citations
19. 19*

    On the Polyakov-Mellin bootstrap

    Rajesh Gopakumar🇮🇳 · Aninda Sinha🇮🇳

    We elaborate on some general aspects of the crossing symmetric approach of Polyakov to the conformal bootstrap, as recently formulated in Mellin space. This approach uses, as building blocks, Witten diagrams in AdS. We show the necessity for having contact Witten diagrams, in addition to the exchange ones, in two different contexts: a) the large $c$ expansion of the holographic bootstrap b) in the $ϵ$ expansion at subleading orders to the ones studied already. In doing so, we use alternate simplified representations of the Witten diagrams in Mellin space. This enables us to also obtain compact, explicit expressions (in terms of a ${}_7{F}_6$ hypergeometric function!) for the analogue of the crossing kernel for Witten diagrams i.e., the decomposition into $s$-channel partial waves of crossed channel exchange diagrams.

    ↳ hep-thcond-mat.stat-mechhep-phJHEP(2018)·90 citations
20. 20*

    Rationalizing roots: an algorithmic approach

    Marco Besier🇩🇪 · Duco van Straten🇩🇪 · Stefan Weinzierl🇩🇪

    In the computation of Feynman integrals which evaluate to multiple polylogarithms one encounters quite often square roots. To express the Feynman integral in terms of multiple polylogarithms, one seeks a transformation of variables, which rationalizes the square roots. In this paper, we give an algorithm for rationalizing roots. The algorithm is applicable whenever the algebraic hypersurface associated with the root has a point of multiplicity $(d-1)$, where $d$ is the degree of the algebraic hypersurface. We show that one can use the algorithm iteratively to rationalize multiple roots simultaneously. Several examples from high energy physics are discussed.

    ↳ hep-thhep-phmath-phmath.MPCommun.Num.Theor.Phys.(2019)·92 citations
21. 21*

    Hadron Multiplicity and Fragmentation in SIDIS

    N. Pierre🇫🇷

    COMPASS final results on multiplicities of charged hadrons and of identified pions and kaons produced in the deep inelastic muon scattering off an isoscalar target are presented and compared to HERMES results. Measurements are done in bins of x, y and z in a wide kinematic range. The hadron and pion data show a good agreement with (N)LO QCD expectations. The kaon data are long awaited for since they are needed to extract kaon fragmentation functions, a crucial ingredient in solving the strange quark polarisation puzzle. COMPASS results for kaons differ from the expectations of the old NLO DSS fit and they cannot be well described by LO QCD either. In this context the importance of $K^{-}$/$K^{+}$ multiplicity ratio at high z is discussed.

    ↳ hep-exhep-ph0 citations
22. 22*

    Fast resonance decays in nuclear collisions

    Aleksas Mazeliauskas🇩🇪 · Stefan Floerchinger🇩🇪 · Eduardo Grossi🇩🇪 · Derek Teaney🇺🇸

    In the context of ultra-relativistic nuclear collisions, we present a fast method for calculating the final particle spectra after the direct decay of resonances from a Cooper-Frye integral over the freeze-out surface. The method is based on identifying components of the final particle spectrum that transform in an irreducible way under rotations in the fluid-restframe. Corresponding distribution functions can be pre-computed including all resonance decays. Just a few of easily tabulated scalar functions then determine the Lorentz invariant decay spectrum from each space-time point, and simple integrals of these scalar functions over the freeze-out surface determine the final decay products. This by-passes numerically costly event-by-event calculations of the intermediate resonances. The method is of considerable practical use for making realistic data to model comparisons of the identified particle yields and flow harmonics, and for studying the viscous corrections to the freeze-out distribution function.

    ↳ nucl-thhep-phEPJC(2019)·48 citations
23. 23*

    Measuring chiral gravitational waves in Chern-Simons gravity with CMB bispectra

    Nicola Bartolo🇮🇹 · Giorgio Orlando🇮🇹 · Maresuke Shiraishi🇯🇵

    Chern-Simons gravity coupled to the scalar sector through a generic coupling function $f(\varphi )$ can be tested at the very high energies of the inflationary period. In 1706.04627, we computed the theoretical parity breaking signatures of the $⟨\gamma \gamma \zeta ⟩$ primordial bispectrum which mixes two gravitons and one scalar curvature perturbation. We defined a parameter $\Pi$ which measures the level of parity breaking of the corresponding bispectrum. In this work we forecast the expected $1\sigma$ error on $\Pi$ using the cosmic microwave background (CMB) angular bispectra. We find that, given the angular resolution of an experiment like $Planck$, $\Pi \sim 10^6$ is detectable via the measurement of $BBT$ or $BBE$ angular bispectra if the tensor-to-scalar ratio $r=0.01$. We also show that, from the theoretical point of view, $\Pi$ can be greater than $10^6$. Thus, our conclusion is that $BBT$ or $BBE$ CMB angular bispectra can become an essential observable for testing Chern-Simons gravity in the primordial universe.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2019)·89 citations
24. 24*

    A Non-Perturbative Definition of the Standard Models

    Juven Wang🇺🇸 · Xiao-Gang Wen🇺🇸

    The Standard Models contain chiral fermions coupled to gauge theories. It has been a long-standing problem to give such gauged chiral fermion theories a quantum non-perturbative definition. By classification of quantum anomalies and symmetric invertible topological orders via a mathematical cobordism theorem for differentiable and triangulable manifolds, and the existence of symmetric gapped boundary for the trivial symmetric invertible topological orders, we propose that Spin(10) chiral fermion theories with Weyl fermions in 16-dimensional spinor representations can be defined on a 3+1D lattice, and subsequently dynamically gauged to be a Spin(10) chiral gauge theory. As a result, the Standard Models from the 16n-chiral fermion SO(10) Grand Unification can be defined non-perturbatively via a 3+1D local lattice model of bosons or qubits. Furthermore, we propose that Standard Models from the 15n-chiral fermion SU(5) Grand Unification can also be realized by a 3+1D local lattice model of fermions.

    ↳ hep-thcond-mat.str-elhep-lathep-ph+1PRResearch(2020)·74 citations
25. 25*

    The Physical Essence of Pulsar Glitch

    Qiu-He Peng🇨🇳 · Jing-Jing Liu🇨🇳 · Chih-Kang Chou🇨🇳

    Based on the magnetic dipole radiation from the 3P2 neutron superfluid vortices (3P2NSFV) in neutron stars, we propose a model of glitch for young pulsars by oscillation between B phase and A phase of 3P2 Neutron superfluid. The main behavior of glitches of pulsars may be naturally explained by our model.

    ↳ astro-ph.HEhep-ph0 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.