Fri·Jul 19, 2019Friday·July 19, 2019

1. 01*

   Strong constraints on non-standard neutrino interactions: LHC vs. IceCube

   Sujata Pandey🇮🇳 · Siddhartha Karmakar🇮🇳 · Subhendu Rakshit🇮🇳

   We find the constraints on various non-standard interactions (NSI) of neutrinos from monojet+MET searches at the Large Hadron Collider (LHC). Also, we show that the measurement of neutrino-nucleon cross-section from the observation of high energy astrophysical neutrino events at IceCube facilitates strong constraints on NSI as well. To this end, we pursue a comparative study of the prospects of LHC and IceCube in detecting NSI, also mentioning the role of low-energy experiments. We discuss the case of NSI with a new vector boson $Z^{\prime }$ and it is found that for some range of $m_{Z^{\prime }}$ LHC puts more stringent bound, whereas IceCube supersedes elsewhere. We also pay special attention to the case of $Z^{\prime }$ of mass of a few GeVs, pointing out that the IceCube constraints can surpass those from LHC and low-energy experiments. Although, for contact-type effective interactions with two neutrinos and two partons, constraints from LHC are superior.

   hep-phJHEP(2019)·22 citations
2. 02*

   PDF Profiling Using the Forward-Backward Asymmetry in Neutral Current Drell-Yan Production

   Elena Accomando · Juri Fiaschi · Francesco Hautmann · Stefano Moretti · the xFitter Developers' team: · Hamed Abdolmaleki · Valerio Bertone · Francesco Giuli · Alexander Glazov · Agnieszka Luszczak · Ivan Novikov · Fred Olness · Oleksandr Zenaiev

   Non-perturbative QCD effects from Parton Distribution Functions (PDFs) may be constrained by using high-statistics Large Hadron Collider (LHC) data. Drell-Yan (DY) measurements in the Charged Current (CC) case provide one of the primary means to do this, in the form of the lepton charge asymmetry. We investigate here the impact of measurements in Neutral Current (NC) DY data mapped onto the Forward-Backward Asymmetry ($A_{\mathrm{FB}}$) on PDF determinations, by using the open source fit platform {\tt{xFitter}}. We demonstrate the potential impact of $A_{\mathrm{FB}}$ data on PDF determinations and perform a thorough analysis of related uncertainties.

   hep-phJHEP(2019)·36 citations
3. 03*

   Dark matter as the origin of neutrino mass in the inverse seesaw mechanism

   Sanjoy Mandal🇪🇸 · Nicolás Rojas🇨🇱 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸

   We propose that neutrino masses are "seeded" by a dark sector within the inverse seesaw mechanism. This way we have a new, "hidden", variant of the scotogenic scenario for radiative neutrino masses. We discuss both explicit and dynamical lepton number violation. In addition to invisible Higgs decays with majoron emission, we discuss in detail the pheneomenolgy of dark matter, as well as the novel features associated to charged lepton flavour violation, and neutrino physics.

   hep-phastro-ph.COPLB(2021)·44 citations
4. 04*

   Reduced uncertainty of the axial $\gamma Z$-box correction to the proton's weak charge

   Jens Erler🇩🇪 · Mikhail Gorchtein🇩🇪 · Oleksandr Koshchii🇩🇪 · Chien-Yeah Seng🇩🇪 · Hubert Spiesberger🇩🇪

   We present the fully up-to-date calculation of the $\gamma Z$-box correction which needs to be taken into account to determine the weak mixing angle at low energies from parity-violating electron proton scattering. We make use of neutrino and antineutrino inclusive scattering data to predict the parity-violating structure function $F_3^{\gamma Z}$ by isospin symmetry. Our new analysis confirms previous results for the axial contribution to the $\gamma Z$-box graph, and reduces the uncertainty by a factor of~2. In addition, we note that the presence of parity-violating photon-hadron interactions induces an additional contribution via $F_3^{\gamma \gamma }$. Using experimental and theoretical constraints on the nucleon anapole moment we are able to estimate the uncertainty associated with this contribution. We point out that future measurements are expected to significantly reduce this latter uncertainty.

   hep-phhep-exnucl-exnucl-thPRD(2019)·13 citations
5. 05*

   Fermionic dark matter via UV and IR freeze-in and its possible X-ray signature

   Anirban Biswas🇮🇳 · Sougata Ganguly🇮🇳 · Sourov Roy🇮🇳

   Non-observation of any dark matter signature at various direct detection experiments over the last decade keeps indicating that immensely popular WIMP paradigm may not be the actual theory of particle dark matter. Non-thermal dark matter produced through freeze-in is an attractive proposal, naturally explaining null results by virtue of its feeble couplings with the Standard Model (SM) particles. We consider a minimal extension of the SM by two gauge singlet fields namely, a ${\mathbb{Z}}_2$-odd fermion $\chi$ and a pseudo scalar $\tilde{\varphi }$, where the former has interactions with the SM particles only at dimension five level and beyond. This introduces natural suppression in the interactions of $\chi$ by a heavy new physics scale $\Lambda$ and forces $\chi$ to be a non-thermal dark matter candidate. We have studied production of $\chi$ in detail taking into account both ultra-violate (UV), infra-red (IR) as well as mixed UV-IR freeze-in and found that for $10^{10}\mathrm{GeV}\le \Lambda \le 10^{15}\mathrm{GeV}$, $\chi$ is dominantly produced via UV and mixed UV-IR freeze-in when reheat temperature $T_{RH}\gtrsim 10^4$ GeV and below which the production is dominated by IR and mixed freeze-in. Furthermore, we have considered the cascade annihilation $\chi \bar{\chi }\to \tilde{\varphi }\tilde{\varphi }\to 4\gamma$ to address the longstanding $\sim 3.5$ keV X-ray line observed from various galaxies and galaxy clusters. We have found that the long-lived intermediate state $\tilde{\varphi }$ modifies dark matter density around the galactic centre to an effective density ${\rho }_{eff}$ which strongly depends on the decay length of $\tilde{\varphi }$. Finally, the allowed parameter space in $\Lambda -g$ plane ($g$ is the coupling between $\chi \bar{\chi }$ and $\tilde{\varphi }$) is obtained by comparing our result with the XMM Newton observed X-ray flux from the centre of Milky Way galaxy in $2\sigma$ range.

   hep-phJCAP(2020)·34 citations
6. 06*

   $Z_3$ meta-stable states in PNJL model

   Minati Biswal🇮🇳 · Sanatan Digal🇮🇳 · P. S. Saumia🇷🇺

   We study the Z 3 meta-stable states in the Polyakov loop Nambu-Jona-Lasinio (PNJL) model. These states exist for temperatures above T m ~ 194 MeV and can decay via bubble nucleation. We numerically solve the bounce equation to compute the nucleation rate. We speculate that, in the context of heavy-ion collisions, the likely scenario for the decay of the meta-stable states is via spinodal decomposition.

   hep-phhep-thnucl-thPRD(2020)·8 citations
7. 07*

   The $O(4)$ ${\varphi }^4$ model as an effective light meson theory: A lattice-continuum comparison

   Gergely Markó🇭🇺 · Zsolt Szép🇭🇺

   We investigate the possibility of using the 4 dimensional $O(4)$ symmetric ${\varphi }^4$ model as an effective theory for the sigma-pion system. We carry out lattice Monte Carlo simulations to establish the triviality bound in the case of explicitly broken symmetry and to compare it with results from continuum functional methods. In case of a physical parametrization we find that triviality restricts the possible lattice spacings to a narrow range, therefore cutoff independence in the effective theory sense is practically impossible for thermal quantities. We match the critical line in the space of bare couplings in the different approaches and compare vacuum physical quantities along the line of constant physics (LCP).

   hep-phhep-latPRD(2019)·2 citations
8. 08*

   $N^{\ast }(1535)\to N$ transition form-factors due to the axial current

   T. M. Aliev🇹🇷 · T. Barakat🇸🇦 · K. Simsek🇹🇷

   The form-factors for the transition $N^{\ast }(1535)\to N$ induced by isovector and isoscalar axial currents within the framework of light-cone QCD sum rules by using the most general form of the interpolating current are calculated. In numerical calculations, we use two sets of values of input parameters. It is observed that the $Q^2$ dependence of the form-factor $G_A$ can be described by the dipole form. Moreover, the form-factors $G_P^{(S)}$ are found to be highly sensitive to the variations in the auxiliary parameter $\beta$.

   hep-phPRD(2019)·6 citations
9. 09*

   What attracts to attractors?

   Aleksi Kurkela🇨🇭 · Wilke van der Schee🇨🇭 · Urs Achim Wiedemann🇨🇭 · Bin Wu🇨🇭

   Whether, how, and to what extent solutions of Bjorken-expanding systems become insensitive to aspects of their initial conditions is of importance for heavy-ion collisions. Here we study 1+1D and phenomenologically relevant boost-invariant 3+1D systems in which initial conditions approach a universal attractor solution. In Israel-Stewart theory (IS) and kinetic theory where the universal attractor extends to arbitrarily early times, we show that all initial conditions approach the attractor at early times by a power-law while their approach is exponential at late times. In these theories, the physical mechanisms of hydrodynamization operational at late times do not drive the approach to the attractor at early times, and the early-time attractor is reached prior to hydrodynamization. In marked contrast, the attractor in strongly coupled systems is realized concurrent with hydrodynamization. This qualitative difference may offer a basis for discriminating weakly and strongly coupled scenarios of heavy-ion collisions.

   hep-phnucl-thPRL(2020)·147 citations
10. 10*

    Maximal Tests in Minimal Gravity

    Jay D. Tasson🇺🇸

    Recent tests have generated impressive reach in the gravity sector of the Standard-Model Extension. This contribution to the CPT'19 proceedings summarizes this progress and maps the structure of work in the gravity sector.

    hep-phgr-qc5 citations
11. 11*

    $(g-2{)}_{\mu ,e}$ and the ANITA anomalous events in a three-loop neutrino mass model

    Mohammad Abdullah🇺🇸 · Bhaskar Dutta🇺🇸 · Sumit Ghosh🇺🇸 · Tianjun Li🇨🇳

    The most recent measurement of the fine structure constant leads to a 2.4 $\sigma$ deviation in the electron anomalous magnetic moment $g_e$-2, while the muon anomalous magnetic moment $g_{\mu }$-2 has a long standing 3.7 $\sigma$ deviation in the opposite direction. We show that these deviations can be explained in a three-loop neutrino mass model based on an $E_6$ Grand Unified Theory. We also study the impact such a model can have on the anomalous events observed by the ANITA experiment and find an insufficient enhancement of the event rate.

    hep-phPRD(2019)·54 citations
12. 12*

    Quarks and light (pseudo-)scalar mesons at finite chemical potential

    Pascal J. Gunkel🇩🇪 · Christian S. Fischer🇩🇪 · Philipp Isserstedt🇩🇪

    We investigate the properties of light scalar and pseudoscalar mesons at finite (light) quark chemical potential. To this end we solve a coupled set of (truncated) Dyson-Schwinger equations for the quark and gluon propagators in Landau-gauge QCD and extent earlier results for $N_f=2+1$ dynamical quark flavors to finite chemical potential at zero temperature. We then determine the meson bound state masses, wave functions, and decay constants for chemical potentials below the first-order phase transition from their homogeneous Bethe-Salpeter equation. We study the changes in the quark dressing functions and Bethe-Salpeter wave functions with chemical potential. In particular, we trace charge-conjugation parity breaking. Furthermore, we confirm the validity of the Silver-Blaze property: all dependencies of colored quantities on chemical potential cancel out in observables and we observe constant masses and decay constants up to and into the coexistence region of the first-order chiral phase transition.

    hep-phEPJA(2019)·28 citations
13. 13*

    Updates of PDFs in the MMHT framework

    R.S. Thorne🇬🇧 · S. Bailey🇬🇧 · T. Cridge🇬🇧 · L.A. Harland-Lang🇬🇧 · A.D. Martin🇬🇧 · R. Nathvani🇬🇧

    We summarise recent developments in the path towards the "MMHT19" parton distribution functions. We concentrate on the extraction of the strange quark upon the improvement of theoretical calculations for NNLO charged current cross sections; the effect of an extension of our parameterisation; and the role of correlated uncertainties in some data sets which prove difficult to fit.

    hep-phhep-exPoS(2019)·22 citations
14. 14*

    Strangeness neutrality and the QCD phase diagram

    Fabian Rennecke🇺🇸 · Wei-jie Fu🇨🇳 · Jan M. Pawlowski🇩🇪

    Since the incident nuclei in heavy-ion collisions do not carry strangeness, the global net strangeness of the detected hadrons has to vanish. We show that there is an intimate relation between strangeness neutrality and baryon-strangeness correlations. In the context of heavy-ion collisions, the former is a consequence of quark number conservation of the strong interactions while the latter are sensitive probes of the character of QCD matter. We investigate the sensitivity of baryon-strangeness correlations on the freeze-out conditions of heavy-ion collisions by studying their dependence on temperature, baryon- and strangeness chemical potential. The impact of strangeness neutrality on the QCD equation of state at finite chemical potentials will also be discussed. We model the low-energy sector of QCD by an effective Polyakov loop enhanced quark-meson model with 2+1 dynamical quark flavors and use the functional renormalization group to account for the non-perturbative quantum fluctuations of hadrons.

    hep-phnucl-thPoS(2019)·9 citations
15. 15*

    Neural Networks for Full Phase-space Reweighting and Parameter Tuning

    Anders Andreassen🇺🇸 · Benjamin Nachman🇺🇸

    Precise scientific analysis in collider-based particle physics is possible because of complex simulations that connect fundamental theories to observable quantities. The significant computational cost of these programs limits the scope, precision, and accuracy of Standard Model measurements and searches for new phenomena. We therefore introduce Deep neural networks using Classification for Tuning and Reweighting (DCTR), a neural network-based approach to reweight and fit simulations using all kinematic and flavor information -- the full phase space. DCTR can perform tasks that are currently not possible with existing methods, such as estimating non-perturbative fragmentation uncertainties. The core idea behind the new approach is to exploit powerful high-dimensional classifiers to reweight phase space as well as to identify the best parameters for describing data. Numerical examples from $e^{+}{e}^{-}\to \text{jets}$ demonstrate the fidelity of these methods for simulation parameters that have a big and broad impact on phase space as well as those that have a minimal and/or localized impact. The high fidelity of the full phase-space reweighting enables a new paradigm for simulations, parameter tuning, and model systematic uncertainties across particle physics and possibly beyond.

    hep-phhep-exstat.MLPRD(2020)·120 citations
16. 16*

    On RG flows in Generalized Effective Field Theory

    Nikos Irges🇬🇷 · Fotis Koutroulis🇬🇷

    Generalized Effective Field Theory (GEFT) is the non-renormalizable extension of an Effective Field Theory where the Wilson coefficients are endowed by their own, independent scale dependence. Such an effective theory can be constructed by quantizing a Lagrangian in the presence of all internal symmetry respecting operators of any mass dimension. The resulting theory may be practically useful in regimes of its phase diagram where the perturbative expansion and a truncation of the infinite tower of Higher Dimensional Operators (HDO) are valid. The massless limit of GEFT is especially interesting as the spontaneous breaking of internal symmetry and of scale invariance are correlated.

    ↳ hep-thhep-phNPB(2020)·4 citations
17. 17*

    Asymptotic safety, string theory and the weak gravity conjecture

    Senarath de Alwis🇺🇸 · Astrid Eichhorn🇩🇰 · Aaron Held🇩🇪 · Jan M. Pawlowski🇩🇪 · Marc Schiffer🇩🇪 · Fleur Versteegen🇩🇪

    We propose a scenario with string theory in the deep ultraviolet, an intermediate asymptotically safe scaling regime for gravity and matter, and the Standard Model in the infrared. This could provide a new perspective to tackle challenges of the two models: For instance, the gravitational Renormalization Group flow could connect a negative microscopic to a positive macroscopic cosmological constant, potentially rendering string theory on an anti-de Sitter background observationally viable. Further, the unitarity of a string-theoretic ultraviolet completion could be inherited by an asymptotically safe fixed point, despite the presence of higher-order interactions. We discuss necessary conditions on the scale of asymptotic safety and the string scale for our scenario to be viable. As a first test, we explore the weak-gravity conjecture in the context of asymptotically safe gravity.

    ↳ hep-thgr-qchep-phPLB(2019)·65 citations
18. 18*

    The Minkowski quantum vacuum does not gravitate

    Viacheslav A. Emelyanov🇩🇪

    We show that a non-zero renormalised value of the zero-point energy in $\lambda {\varphi }^4$-theory over Minkowski spacetime is in tension with the scalar-field equation at two-loop order in perturbation theory.

    ↳ hep-thgr-qchep-phNPB(2019)·2 citations
19. 19*

    Revisiting a negative cosmological constant from low-redshift data

    Luca Visinelli🇸🇪 · Sunny Vagnozzi🇸🇪 · Ulf Danielsson🇸🇪

    Persisting tensions between high-redshift and low-redshift cosmological observations suggest the dark energy sector of the Universe might be more complex than the positive cosmological constant of the $\Lambda$CDM model. Motivated by string theory, wherein symmetry considerations make consistent AdS backgrounds (\textit (i.e.) maximally symmetric spacetimes with a negative cosmological constant) ubiquitous, we explore a scenario where the dark energy sector consists of two components: a negative cosmological constant, with a dark energy component with equation of state $w_{\varphi }$ on top. We test the consistency of the model against low-redshift Baryon Acoustic Oscillation and Type Ia Supernovae distance measurements, assessing two alternative choices of distance anchors: the sound horizon at baryon drag determined by the \textit{Planck} collaboration, and the Hubble constant determined by the SH0ES program. We find no evidence for a negative cosmological constant, and mild indications for an effective phantom dark energy component on top. A model comparison analysis reveals the $\Lambda$CDM model is favoured over our negative cosmological constant model. While our results are inconclusive, should low-redshift tensions persist with future data, it would be worth reconsidering and further refining our toy negative cosmological constant model by considering realistic string constructions.

    ↳ astro-ph.COgr-qchep-phhep-thSymmetry(2019)·205 citations
20. 20*

    Search of cluster structure in nuclei via analysis of bremsstrahlung emission

    Sergei P. Maydanyuk (2 and 3)🇨🇳 · Peng-Ming Zhang (1 and 2)🇨🇳 · Li-Ping Zou (2) ((1) School of Physics and Astronomy, Sun Yat-Sen University, Zhuhai, China, (2) Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China, (3) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kiev, 03680, Ukraine)🇨🇳

    We investigate emission of bremsstrahlung photons during scattering of $\alpha$-particles off nuclei. For that, we construct bremsstrahlung model for $\alpha$-nucleus scattering, where a new formalism for coherent and incoherent bremsstrahlung emissions in elastic scattering and mechanisms in inelastic scattering is added. Basing of this approach, we analyze experimental bremsstrahlung cross-sections in the scattering of $\alpha$-particles off the \isotope[59]{Co}, \isotope[116]{Sn}, \isotope[\rm nat]{Ag} and \isotope[197]{Au} nuclei at 50 MeV of $\alpha$-particles beam measured at the Variable Energy Cyclotron Centre, Calcutta. We observe oscillations in the calculated spectra for elastic scattering for each nucleus. But, for \isotope[59]{Co}, \isotope[116]{Sn} and \isotope[\rm nat]{Ag} we obtain good agreement between calculated coherent spectrum with incoherent contribution for elastic scattering with experimental data in the full photon energy region. For heavy nucleus \isotope[197]{Au} we find that (1) Oscillating behavior of the calculated spectrum of coherent emission in elastic scattering is in disagreement with experimental data, (2) Inclusion of incoherent emission improves description of the data, but summarized spectrum is in satisfactory agreement with the experimental data. To understand unknown modification of wave function for scattering, we add new mechanisms of inelastic scattering to calculations and extract information about unknown new amplitude of such mechanisms from experimental data analysis. This amplitude has maxima at some energies, that characterizes existence of states of the most compact structures (clusters) in nucleus-target. We explain origin of oscillations in the bremsstrahlung spectra for elastic scattering (at first time). New information about coherent and incoherent contributions is extracted for studied reactions.

    ↳ nucl-thhep-phnucl-ex2 citations
21. 21*

    Cosmological searches for the neutrino mass scale and mass ordering

    Sunny Vagnozzi🇸🇪

    In this thesis, I describe a number of recent important developments in neutrino cosmology on three fronts. Firstly, focusing on Large-Scale Structure (LSS) data, I will show that current cosmological probes contain a wealth of information on the sum of the neutrino masses. I report on the analysis leading to the currently best upper limit on the sum of the neutrino masses of $0.12\mathrm{eV}$. I show how cosmological data exhibits a weak preference for the normal neutrino mass ordering because of parameter space volume effects, and propose a simple method to quantify this preference. Secondly, I will discuss how galaxy bias represents a severe limitation towards fully capitalizing on the neutrino information hidden in LSS data. I propose a method for calibrating the scale-dependent galaxy bias using CMB lensing-galaxy cross-correlations. Moreover, in the presence of massive neutrinos, the usual definition of bias becomes inadequate, as it leads to a scale-dependence on large scales which has never been accounted for. I show that failure to define the bias appropriately will be a problem for future LSS surveys, and propose a simple recipe to account for the effect of massive neutrinos on galaxy bias. Finally, I discuss implications of correlations between neutrino parameters and other cosmological parameters. In non-phantom dynamical dark energy models, the upper limit on the sum of the neutrino masses becomes tighter than the $\Lambda$CDM limit. Therefore, such models exhibit an even stronger preference for the normal ordering, and their viability could be jeopardized should near-future laboratory experiments determine that the mass ordering is inverted. I then discuss correlations between neutrino and inflationary parameters. I find that our determination of inflationary parameters is stable against assumptions about the neutrino sector. (abridged)

    ↳ astro-ph.COgr-qchep-ph34 citations
22. 22*

    Ionization from Cosmic Strings at Cosmic Dawn

    Samuel Laliberte🇨🇦 · Robert Brandenberger (McGill University)🇨🇦

    Cosmic strings produce charged particles which, by emitting electromagnetic radiation, partially ionize neutral hydrogen during the dark ages. Corrections to the ionization fraction of neutral hydrogen induced by cosmic strings could lead to new observational effects and/or new constraints on the string tension around $G\mu \sim 10^{-16}-10^{-22}$ for values of the primordial magnetic field in the range $B_0\sim 10^{-11}-10^{-9}$ Gauss.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·8 citations
23. 23*

    Nuclear electric dipole moment in the cluster model with a triton: ${}^7$Li and ${}^{11}$B

    Nodoka Yamanaka🇫🇷 · Taiichi Yamada🇯🇵 · Yasuro Funaki🇯🇵

    We calculate the electric dipole moment (EDM) of the nuclei ${}^7$Li and ${}^{11}$B in the cluster model with $\alpha$ (${}^4$He) and triton (${}^3$H) clusters as degrees of freedom. The ${}^7$Li and ${}^{11}$B nuclei are treated in the two- and three-body problem, respectively, using the Gaussian expansion method, assuming the one-meson exchange P, CP-odd nuclear forces. We find that ${}^7$Li and ${}^{11}$B have larger sensitivity to the CP violation than the deuteron. It is also suggested that the EDMs of ${}^7$Li and ${}^{11}$B, together with those of ${}^6$Li, ${}^9$Be and the $1/2_1^{+}$ excited state of ${}^{13}$C, obey an approximate counting rule accounting for the EDM of the cluster and the $\alpha -N$ polarization. We show their sensitivity on the hadronic level CP violation in terms of the chiral effective field theory, and discuss their role in probing new physics beyond the standard model.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2019)·20 citations
24. 24*

    Abelian Higgs model at four loops, fixed-point collision and deconfined criticality

    Bernhard Ihrig🇩🇪 · Nikolai Zerf🇩🇪 · Peter Marquard🇩🇪 · Igor F. Herbut🇨🇦 · Michael M. Scherer🇩🇪

    The abelian Higgs model is the textbook example for the superconducting transition and the Anderson-Higgs mechanism, and has become pivotal in the description of deconfined quantum criticality. We study the abelian Higgs model with $n$ complex scalar fields at unprecedented four-loop order in the $4-ϵ$ expansion and find that the annihilation of the critical and bicritical points occurs at a critical number of $n_c\approx 182.95\left(1-1.752ϵ+0.798{ϵ}^2+0.362{ϵ}^3\right)+\mathcal{O}\left({ϵ}^4\right)$. Consequently, below $n_c$, the transition turns from second to first order. Resummation of the series to extract the result in three-dimensions provides strong evidence for a critical $n_c(d=3)$ which is significantly below the leading-order value, but the estimates for $n_c$ are widely spread. Conjecturing the topology of the renormalization group flow between two and four dimensions, we obtain a smooth interpolation function for $n_c(d)$ and find $n_c(3)\approx 12.2\pm 3.9$ as our best estimate in three dimensions. Finally, we discuss Miransky scaling occurring below $n_c$ and comment on implications for weakly first-order behavior of deconfined quantum transitions. We predict an emergent hierarchy of length scales between deconfined quantum transitions corresponding to different $n$.

    ↳ cond-mat.str-elhep-phhep-thPRB(2019)·89 citations
25. 25*

    Testing cosmology and fundamental physics with the Cherenkov Telescope Array

    H. Martínez-Huerta🇧🇷 · J. Biteau🇫🇷 · J. Lefaucheur🇫🇷 · M. Meyer🇺🇸 · S. Pita🇫🇷 · I. Vovk (for the CTA Consortium)🇩🇪

    The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory for $\gamma$-ray astronomy at energies above 30 GeV. Thanks to its unique capabilities, CTA observations will address a plethora of open questions in astrophysics ranging from the origin of cosmic messengers to the exploration of the frontiers of physics. In this note, we present a comprehensive sensitivity study to assess the potential of CTA to measure the $\gamma$-ray absorption on the extragalactic background light (EBL), to constrain or detect intergalactic magnetic fields (IGMFs), and probe physics beyond the Standard Model such as axion-like particles (ALPs) and Lorentz invariance violation (LIV), which could modify the $\gamma$-ray spectra features expected from EBL absorption. Our results suggest that CTA will have unprecedented sensitivity to detect IGMF signatures and will probe so-far unexplored regions of the LIV and ALP parameter space. Furthermore, an indirect measurement of the EBL and of its evolution will be performed with unrivaled precision.

    ↳ astro-ph.HEhep-phPoS(2020)·2 citations
26. 26*

    Pion and Kaon Structure at the Electron-Ion Collider

    Arlene C. Aguilar🇧🇷 · Zafir Ahmed🇨🇦 · Christine Aidala🇺🇸 · Salina Ali🇺🇸 · Vincent Andrieux🇺🇸 · John Arrington🇺🇸 · Adnan Bashir🇲🇽 · Vladimir Berdnikov🇺🇸 · Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · Chen Chen🇩🇪 · Muyang Chen🇨🇳 and 39 other authors

    Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. This challenge entails the questions of how does the roughly 1 GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe.

    ↳ nucl-exhep-exhep-lathep-ph+1EPJA(2019)·210 citations
27. 27*

    If the Weak Were Strong and the Strong Were Weak

    Nakarin Lohitsiri🇬🇧 · David Tong🇬🇧

    We explore the phase structure of the Standard Model as the relative strengths of the SU(2) weak force and SU(3) strong force are varied. With a single generation of fermions, the structure of chiral symmetry breaking suggests that there is no phase transition as we interpolate between the SU(3)-confining phase and the SU(2)-confining phase. Remarkably, the massless left-handed neutrino, familiar in our world, morphs smoothly into a massless right-handed down-quark. With multiple generations, a similar metamorphosis occurs, but now proceeding via a phase transition. In the second half of the paper we introduce a two-parameter extension of the Standard Model, a chiral gauge theory with gauge group U(1) x Sp(r) x SU(N). We again explore the phase structure of the theory as the relative strengths of the Sp(r) and SU(N) gauge couplings vary.

    ↳ hep-thhep-phSciPost Phys.(2019)·12 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.