Wed·Aug 29, 2018Wednesday·August 29, 2018

1. 01*

   Resonant Di-Higgs Production at Gravitational Wave Benchmarks: A Collider Study using Machine Learning

   Alexandre Alves🇧🇷 · Tathagata Ghosh🇺🇸 · Huai-Ke Guo🇺🇸 · Kuver Sinha🇺🇸

   We perform a complementarity study of gravitational waves and colliders in the context of electroweak phase transitions choosing as our template the xSM model, which consists of the Standard Model augmented by a real scalar. We carefully analyze the gravitational wave signal at benchmark points compatible with a first order phase transition, taking into account subtle issues pertaining to the bubble wall velocity and the hydrodynamics of the plasma. In particular, we comment on the tension between requiring bubble wall velocities small enough to produce a net baryon number through the sphaleron process, and large enough to obtain appreciable gravitational wave production. For the most promising benchmark models, we study resonant di-Higgs production at the high-luminosity LHC using machine learning tools: a Gaussian process algorithm to jointly search for optimum cut thresholds and tuning hyperparameters, and a boosted decision trees algorithm to discriminate signal and background. The multivariate analysis on the collider side is able either to discover or provide strong statistical evidence of the benchmark points, opening the possibility for complementary searches for electroweak phase transitions in collider and gravitational wave experiments.

   hep-phJHEP(2018)·67 citations
2. 02*

   QCD or What?

   Theo Heimel🇩🇪 · Gregor Kasieczka🇩🇪 · Tilman Plehn🇩🇪 · Jennifer M Thompson🇩🇪

   Autoencoder networks, trained only on QCD jets, can be used to search for anomalies in jet-substructure. We show how, based either on images or on 4-vectors, they identify jets from decays of arbitrary heavy resonances. To control the backgrounds and the underlying systematics we can de-correlate the jet mass using an adversarial network. Such an adversarial autoencoder allows for a general and at the same time easily controllable search for new physics. Ideally, it can be trained and applied to data in the same phase space region, allowing us to efficiently search for new physics using un-supervised learning.

   hep-phSciPost Phys.(2019)·227 citations
3. 03*

   Anomalous dimensions and splitting functions beyond the next-to-next-to-leading order

   A. Vogt (Liverpool U., Dept. Math.)🇬🇧 · F. Herzog (NIKHEF, Amsterdam)🇳🇱 · S. Moch (Hamburg U., Inst. Theor. Phys. II)🇩🇪 · B. Ruijl (Zurich, ETH)🇨🇭 · T. Ueda (Seikei U.)🇯🇵 · J.A. M. Vermaseren (NIKHEF, Amsterdam)🇳🇱

   We report on recent progress on the splitting functions for the evolution of parton distributions and related quantities, the (lightlike) cusp anomalous dimensions, in perturbative QCD. New results are presented for the four-loop (next-to-next-to-next-to-leading order, N^3LO) contributions to the flavour-singlet splitting functions and the gluon cusp anomalous dimension. We present first results, the moments N=2 and N=3, for the five-loop (N^4LO) non-singlet splitting functions.

   hep-phPoS(2018)·29 citations
4. 04*

   Searching for New Physics with Deep Autoencoders

   Marco Farina🇺🇸 · Yuichiro Nakai🇺🇸 · David Shih🇺🇸

   We introduce a potentially powerful new method of searching for new physics at the LHC, using autoencoders and unsupervised deep learning. The key idea of the autoencoder is that it learns to map "normal" events back to themselves, but fails to reconstruct "anomalous" events that it has never encountered before. The reconstruction error can then be used as an anomaly threshold. We demonstrate the effectiveness of this idea using QCD jets as background and boosted top jets and RPV gluino jets as signal. We show that a deep autoencoder can significantly improve signal over background when trained on backgrounds only, or even directly on data which contains a small admixture of signal. Finally we examine the correlation of the autoencoders with jet mass and show how the jet mass distribution can be stable against cuts in reconstruction loss. This may be important for estimating QCD backgrounds from data. As a test case we show how one could plausibly discover 400 GeV RPV gluinos using an autoencoder combined with a bump hunt in jet mass. This opens up the exciting possibility of training directly on actual data to discover new physics with no prior expectations or theory prejudice.

   hep-phhep-exPRD(2020)·257 citations
5. 05*

   Small-$x$ Helicity Evolution: an Operator Treatment

   Yuri V. Kovchegov🇺🇸 · Matthew D. Sievert🇺🇸

   We rederive the small-$x$ evolution equations governing quark helicity distribution in a proton using solely an operator-based approach. In our previous works on the subject, the evolution equations were derived using a mix of diagrammatic and operator-based methods. In this work, we re-derive the double-logarithmic small-$x$ evolution equations for quark helicity in terms of the "polarized Wilson lines", the operators consisting of light-cone Wilson lines with one or two non-eikonal local operator insertions which bring in helicity dependence. For the first time we give explicit and complete expressions for the quark and gluon polarized Wilson line operators, including insertions of both the gluon and quark sub-eikonal operators. We show that the double-logarithmic small-$x$ evolution of the "polarized dipole amplitude" operators, made out of regular light-cone Wilson lines along with the polarized ones constructed here, reproduces the equations derived in our earlier works. The method we present here can be used as a template for determining the small-$x$ asymptotics of any transverse momentum-dependent (TMD) quark (or gluon) parton distribution functions (PDFs), and is not limited to helicity.

   hep-phnucl-thPRD(2019)·117 citations
6. 06*

   Associated production of a top quark with a photon via anomalous couplings

   Matthew Forslund🇺🇸 · Nikolaos Kidonakis🇺🇸

   We discuss the associated production of a top quark with a photon via anomalous $t$-$q$-$\gamma$ couplings, and present higher-order corrections from soft-gluon emission for the processes $gq\to t\gamma$ at LHC energies. We perform soft-gluon resummation at next-to-leading-logarithm accuracy and derive approximate next-to-next-to-leading order (aNNLO) double-differential cross sections. We calculate at aNNLO the total $t\gamma$ production cross sections and the top-quark transverse-momentum and rapidity distributions for various LHC energies, and show that the soft-gluon corrections are large and dominant in these processes.

   hep-phPRD(2018)·14 citations
7. 07*

   Production and Backreaction of Spin-2 Particles of $SU(2)$ Gauge Field during Inflation

   A. Maleknejad🇩🇪 · E. Komatsu🇩🇪

   Primordial SU(2) gauge fields with an isotropic background lead to the production of spin-2 particles during inflation. We provide a unified formalism to compute this effect in all of the inflation models with isotropic SU(2) gauge fields such as Gauge-flation and Chromo-Natural inflation with and without spectator axion fields or the mass of the gauge field from the Higgs mechanism. First, we calculate the number and energy densities of the spin-2 particles. We then obtain exact analytical formulae for their backreaction on the background equations of motion of SU(2) and axion fields in (quasi) de Sitter expansion, which were calculated only numerically for one particular model in the literature. We show that the backreaction is directly related to the number density of the spin-2 field. Second, we relate the number density of the spin-2 particles to the power spectrum and the energy density of the gravitational waves sourced by them. Finally, we use the size of the backreaction to constrain the parameter space of the models. We find that the tensor-to-scalar ratio of the sourced gravitational waves can at most be on the order of that of the vacuum contribution to avoid a large backreaction on slow-roll dynamics of the gauge and axion fields in quasi-de Sitter expansion.

   hep-phgr-qchep-thJHEP(2019)·66 citations
8. 08*

   Melting of scalar hadrons in an AdS/QCD model modified by a thermal dilaton

   Alfredo Vega🇨🇱 · M. A. Martin Contreras🇨🇱

   We consider an AdS/QCD model at finite temperature with a dilaton field that we call thermal because, in addition to depending on the holographic coordinate, it also depends on temperature. We study two thermal dilatons in this work such that at $T=0$ they are reduced to the dilatons used by some authors. With these thermal dilatons it is possible to obtain melting temperatures for mesons close to $180$ MeV and also make predictions for other hadrons. We use a procedure based on the analysis of the holographic potential related to the E.O.M. for modes dual to hadrons to calculate melting temperatures. This technique is easy to implement; therefore, it could be considered a first fast testing criterion for soft wall-like models at finite temperature.

   hep-phNPB(2019)·18 citations
9. 09*

   $W^{+}{W}^{-}$ production at NNLO+PS

   Emanuele Re🇨🇭

   We present predictions for $W^{+}{W}^{-}$ production (with exact decays) that are next-to-next-to-leading order (NNLO) accurate and consistently matched to a parton shower. The matching is achieved by upgrading, with MiNLO, the NLO calculation of $W^{+}{W}^{-}+1$ jet production, in such a way that NLO accuracy is guaranteed for $W^{+}{W}^{-}$ inclusive observables, and by performing subsequently a reweighting of the WWJ-MiNLO events, differential in the $W^{+}{W}^{-}$ Born variables, to the NNLO results obtained with MATRIX.

   hep-phPoS(2018)·0 citations
10. 10*

    Sterile neutrino and leptonic decays of the pseudoscalar mesons

    Chong-Xing Yue🇨🇳 · Ji-Ping Chu🇨🇳

    We consider a scenario with only one sterile neutrino $N$, negligible mixing with the active neutrinos ${\nu }_L$, where its interactions with ordinary particles could be described in a model independent approach based on an effective theory. Under such a framwork, we consider the contributions of the sterile neutrino $N$ to the pure leptonic decays $M\to l\nu$ and $\nu \overline{\nu }$, and the radiative leptonic decays $M\to l\nu \gamma$ with $M$ denoting the pseudoscalar mesons $B$, $D$ and $K$. We find that it can produce significant effects on some of these rare decay processes.

    hep-phPRD(2018)·11 citations
11. 11*

    Two-photon exchange correction to the Lamb shift and hyperfine splitting of S levels

    Oleksandr Tomalak🇩🇪

    We evaluate the two-photon exchange corrections to the Lamb shift and hyperfine splitting of S states in electronic hydrogen relying on modern experimental data and present the two-photon exchange on a neutron inside the electronic and muonic atoms. These results are relevant for the precise extraction of the isotope shift as well as in the analysis of the ground state hyperfine splitting in usual and muonic hydrogen.

    hep-phnucl-exnucl-thphysics.atom-phEPJA(2019)·49 citations
12. 12*

    Determination of contributions from residual light charged hadrons to inclusive charged hadrons from $e^{+}{e}^{-}$ annihilation data

    Alireza Mohamaditabar🇮🇷 · F. Taghavi-Shahri🇮🇷 · Hamzeh Khanpour🇮🇷 · Maryam Soleymaninia🇮🇷

    In this paper, we present an extraction of the contribution from the "{\it residual}" light charged hadrons to the inclusive unidentified light charged hadron fragmentation functions (FFs) at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. Considering the contributions from charged pion, kaon and (anti)proton FFs from recent {\tt NNFF1.0} analysis of charged hadron FFs, we determine the small but efficient {\it residual} charged hadron FFs from QCD analysis of all available single inclusive unidentified charged hadron data sets in electron-positron ($e^{+}{e}^{-}$) annihilations. The zero-mass variable flavor number scheme (ZM-VFNS) has been applied to account the heavy flavor contributions. The obtained optimum set of {\it residual} charged hadron FFs is accompanied by the well-known Hessian technique to assess the uncertainties in the extraction of these new sets of FFs. It is shown that the {\it residual} contributions of charged hadron FFs have very important impact on the inclusive charged hadron FFs and substantially on the quality and the reliability of the QCD fit. Furthermore, this study shows that the {\it residual} contributions become also sizable for the case of heavy quark FFs as well as for the $c$- and $b$-tagged cross sections.

    hep-phhep-exEPJA(2019)·7 citations
13. 13*

    On Higgs boson plus gluon amplitudes at one loop

    R. Keith Ellis🇬🇧 · Satyajit Seth🇬🇧

    We present analytic results for one-loop Higgs boson + $n$-gluon amplitudes for $n\le 5$ in the full theory including all dependence on the (top) quark mass. In this paper we consider only the case where the gluons all have the same helicity. The amplitudes are expressed in simple formula and display similar structure. Their limiting behaviour in small Higgs momentum and large top mass is studied.

    hep-phJHEP(2018)·10 citations
14. 14*

    State of the art POWHEG generators for top mass measurements at the LHC

    Silvia Ferrario Ravasio🇮🇹 · Tomáš Ježo🇨🇭

    We study the theoretical uncertainties in the determination of the top-quark mass using next-to-leading-order (NLO) generators, that describe the top-quark decay at different levels of accuracy, interfaced to parton showers (PS). Specifically we consider one generator that implements NLO corrections only in the production dynamics, one that also takes them into account in the top-quark decay in the narrow width approximation (NWA) and one that implements them exactly, including finite-width and interference effects. We aim at assessing the errors in top-mass determinations of purely theoretical origin. We do so by measuring relative peak position shifts of $Wb$-jet mass distributions. Besides the theoretical errors due to the use of less accurate NLO+PS generators, we also explore uncertainties related to shower and modelling of non-perturbative effects by comparing the results obtained by interfacing our generators to both Pythia and Herwig shower Monte Carlos (SMCs).

    hep-phPoS(2018)·0 citations
15. 15*

    NLO matching for $t\bar{t}b\bar{b}$ production with massive $b$ quarks

    Tomáš Ježo🇨🇭

    Measurements of $t\bar{t}H$ production in the $H\to b\bar{b}$ channel depend in a critical way on the theoretical uncertainty associated with the irreducible QCD $t\bar{t}+b$-jet background. We introduce a new $pp\to t\bar{t}b\bar{b}$ POWHEG generator in the 4F scheme based on POWHEG-BOX-RES and on OpenLoops for fast evaluation of the scattering amplitudes. We present predictions and uncertainties for $t\bar{t}+b$-jet observables at the 13 TeV LHC. We also consider theoretical uncertainties related to the POWHEG matching method and to the parton shower (PS) modelling, with emphasis on $g\to b\bar{b}$ splittings. In general, matching and shower uncertainties turn out to be remarkably small. This is confirmed by a consistent comparison against SHERPA+OpenLoops.

    hep-phPoS(2018)·1 citation
16. 16*

    BBN constraints on MeV-scale dark sectors. Part II. Electromagnetic decays

    Marco Hufnagel🇩🇪 · Kai Schmidt-Hoberg🇩🇪 · Sebastian Wild🇩🇪

    Meta-stable dark sector particles decaying into electrons or photons may non-trivially change the Hubble rate, lead to entropy injection into the thermal bath of Standard Model particles and may also photodisintegrate light nuclei formed in the early universe. We study generic constraints from Big Bang Nucleosynthesis on such a setup, with a particular emphasis on MeV-scale particles which are neither fully relativistic nor non-relativistic during all times relevant for Big Bang Nucleosynthesis. We apply our results to a simple model of self-interacting dark matter with a light scalar mediator. This setup turns out to be severely constrained by these considerations in combination with direct dark matter searches and will be fully tested with the next generation of low-threshold direct detection experiments.

    hep-phastro-ph.COJCAP(2018)·126 citations
17. 17*

    Predicting ${\delta }^{\text{PMNS}}$, ${\theta }_{23}^{\text{PMNS}}$ and fermion mass ratios from flavour GUTs with CSD2

    Stefan Antusch🇨🇭 · Christian Hohl🇨🇭 · Charanjit K. Khosa🇬🇧 · Vasja Susic🇨🇭

    Constrained Sequential neutrino Dominance of type 2 (referred to as CSD2) is an attractive building block for flavour Grand Unified Theories (GUTs) because it predicts a non-zero leptonic mixing angle ${\theta }_{13}^{\text{PMNS}}$, a deviation of ${\theta }_{23}^{\text{PMNS}}$ from $\pi /4$, as well as a leptonic Dirac CP phase ${\delta }^{\text{PMNS}}$ which is directly linked to the CP violation relevant for generating the baryon asymmetry via the leptogenesis mechanism. When embedded into GUT flavour models, these predictions are modified in a specific way, depending on which GUT operators are responsible for generating the entries of fermion Yukawa matrices. In this paper, we systematically investigate and classify the resulting predictions from supersymmetric $\mathrm{SU}(5)$ based flavour models by fitting the known fermion mass and mixing data, in order to provide a roadmap for future model building. Interestingly, the promising models predict the lepton Dirac CP phase ${\delta }^{\mathrm{PMNS}}$ between $230^{\circ }$ and $290^{\circ }$, and the quark CP phase ${\delta }^{\mathrm{CKM}}$ in accordance with a right-angled unitarity triangle (${\alpha }_{\mathrm{UT}}=90^{\circ }$). Also, our model setup predicts the quantities ${\theta }_{23}^{\mathrm{PMNS}}$ and $m_d/m_s$ with less uncertainty than current experimental precision, and allowing with future sensitivity to discriminate between them.

    hep-phJHEP(2018)·15 citations
18. 18*

    TeV Scale Neutrino Mass Generation, Minimal Inelastic Dark Matter, and High Scale Leptogenesis

    Pei-Hong Gu🇨🇳 · Hong-Jian He🇨🇳

    The seesaw and leptogenesis commonly depend on the masses of same particles, and thus are both realized at the same scale. In this work, we demonstrate a new possibility to realize a TeV-scale neutrino seesaw and a natural high-scale leptogenesis. We extend the standard model by two gauge-singlet scalars, a vector-like iso-doublet fermion and one iso-triplet Higgs scalar. Our model respects a softly broken lepton number and an exactly conserved $Z_2$ discrete symmetry. It can achieve three things altogether: (i) realizing a testable type-II seesaw at TeV scale with two nonzero neutrino mass-eigenvalues, (ii) providing a minimal inelastic dark matter from the new fermion doublets, and (iii) accommodating a thermal or nonthermal leptogenesis through the singlet scalar decays. We further analyze the current experimental constraints on our model and discuss the implications for the dark matter direct detections and the LHC searches.

    hep-phastro-ph.COhep-exPRD(2019)·13 citations
19. 19*

    Resolving the ${\varphi }_2$ ($\alpha$) ambiguity in $B\to \rho \rho$

    J. Dalseno🇪🇸

    I propose an alternative method for measuring the $CP$ violating phase ${\varphi }_2$ ($\alpha$) without ambiguity in an extended SU(2) isospin triangle analysis, which can ultimately be achieved by exploiting interference effects between $B^0\to {\rho }^0{\rho }^0$ and $B^0\to a_1^{\pm }{\pi }^{\mp }$ in a time-dependent flavour-tagged amplitude analysis. Under certain assumptions on the effective ${\varphi }_2$ in each channel, I demonstrate with an idealised amplitude model that potential deviations in the measured ${\varphi }_2$ due to penguin contamination in $B^0\to a_1^{\pm }{\pi }^{\mp }$ are sufficiently large within current experimental uncertainties that this programme could be executed with Run 3 data at LHCb and easily at Belle II.

    hep-phJHEP(2018)·7 citations
20. 20*

    The Effective $\Delta m_{ee}^2$ in Matter

    Peter B. Denton🇩🇰 · Stephen J. Parke🇺🇸

    In this paper we generalize the concept of an effective $\Delta m_{ee}^2$ for ${\nu }_e/{\bar{\nu }}_e$ disappearance experiments, which has been extensively used by the short baseline reactor experiments, to include the effects of propagation through matter for longer baseline ${\nu }_e/{\bar{\nu }}_e$ disappearance experiments. This generalization is a trivial, linear combination of the neutrino mass squared eigenvalues in matter and thus is not a simple extension of the usually vacuum expression, although, as it must, it reduces to the correct expression in the vacuum limit. We also demonstrated that the effective $\Delta m_{ee}^2$ in matter is very useful conceptually and numerically for understanding the form of the neutrino mass squared eigenstates in matter and hence for calculating the matter oscillation probabilities. Finally we analytically estimate the precision of this two-flavor approach and numerically verify that it is precise at the sub-percent level.

    hep-phPRD(2018)·11 citations
21. 21*

    Axion absorption and the spin temperature of primordial hydrogen

    Adrien Auriol🇫🇷 · Sacha Davidson🇫🇷 · Georg Raffelt🇩🇪

    An absorption dip in the spectrum of the cosmic microwave background observed by the EDGES experiment suggests an unexplained reduction of the hydrogen spin temperature at cosmic redshift z ~ 17. The mass of dark-matter axions could correspond to the hyperfine splitting of 5.9 micro-eV, between the triplet (H1) and singlet (H0) state. We calculate the rate for a+ H0 <-> H1 in two ways, and find that it is orders of magnitude smaller than the CMB-mediated transition rate, so irrelevant. As a result, this process cannot be used to rule in or out dark matter axions of mass = hyperfine splitting. The axion rate nonetheless has interesting features, for example, on balance it heats the spin temperature, and the axion couplings to protons and electrons contribute on equal footing.

    hep-phastro-ph.COPRD(2019)·17 citations
22. 22*

    Analysis of the doubly heavy baryon states and pentaquark states with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we study the doubly heavy baryon states and pentaquark states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension $7$ and $13$ respectively in a consistent way. In calculations, we separate the contributions of the negative parity and positive parity hadron states unambiguously, and study the masses and pole residues of the doubly heavy baryon states and pentaquark states in details. The present predictions can be confronted to the experimental data in the future.

    hep-phEPJC(2018)·79 citations
23. 23*

    Constraints on the Solar $\Delta m^2$ using Daya Bay & RENO

    Seon-Hee Seo🇰🇷 · Stephen Parke🇺🇸

    We demonstrate that the currently running short baseline reactor experiments, especially Daya Bay, can put a significant upper bound on $\Delta m_{21}^2$. This novel approach to determining $\Delta m_{21}^2$ can be performed with the current data of both Daya Bay \& RENO and provides additional information on $\Delta m_{21}^2$ in a different $L/E$ range ($\sim$ 0.5 km/MeV) for an important consistency check on the 3 flavor massive neutrino paradigm. Upper limits by Daya Bay and RENO and a possible lower limit from Daya Bay, before the end of 2020, will be the only new information on this important quantity until the medium baseline reactor experiment, JUNO, gives a very precise measurement in the middle of the next decade. In this study ${\theta }_{12}$ value is fixed since its impact on the $\Delta m_{21}^2$ measurement is relatively small as discussed in the Appendix.

    ↳ hep-exhep-phPRD(2019)·9 citations
24. 24*

    Searches for h(125) properties beyond the Standard Model at the CMS experiment

    Teresa Lenz🇩🇪

    The discovered Higgs boson with a mass of 125 GeV exhibits properties which are all in agreement with Standard Model predictions. However, the corresponding measurements still allow for a considerable non-Standard Model behavior of the h(125). Beyond Standard Model properties can show up in non-Standard Model decays of the h(125) or in anomalous couplings of the Higgs boson. This article presents four different analyses done at the CMS experiment with 2012 and 2016 data that search for properties of the discovered Higgs boson beyond the Standard Model. These include a search for lepton flavor violating Higgs decays, a search for decays of the h(125) to light Higgs bosons, a search for anomalous contributions to the Higgs trilinear self-coupling, and finally a search for anomalous couplings of the h(125) to vector bosons.

    ↳ hep-exhep-ph1 citation
25. 25*

    Recent progress in the partial-wave analysis of the diffractively produced ${\pi }^{-}{\pi }^{+}{\pi }^{-}$ final state at COMPASS

    Fabian Krinner (for the COMPASS collaboration)🇩🇪

    The COMPASS spectrometer at CERN has collected a large data set for diffractive three-pion production of $46\times 10^6$ exclusive events. Based on previous conventional Partial-Wave Analyses (PWA), we performed a `freed-isobar PWA' on the same data, removing model assumptions on the dynamic isobar amplitudes for dominating waves. In this analysis, we encountered continuous mathematical ambiguities, which we were able to identify and resolve. This analysis gives an unprecedented insight in the interplay of $2\pi$ and $3\pi$ dynamics in the process. As an example we show results for a spin-exotic wave $J_{X^{-}}^{PC}=1^{-+}$ wave.

    ↳ hep-exhep-phEPJ Web Conf.(2019)·3 citations
26. 26*

    Characterizing the local gamma-ray Universe via angular cross-correlations

    Simone Ammazzalorso🇮🇹 · Nicolao Fornengo🇮🇹 · Shunsaku Horiuchi🇺🇸 · Marco Regis🇮🇹

    With a decade of gamma-ray data from the Fermi-LAT telescope, we can now hope to answer how well we know the local Universe at gamma-ray frequencies. On the other hand, with gamma-ray data alone it is not possible to directly access the distance of the emission and to point out the origin of unresolved sources. This obstacle can be overcome by cross-correlating the gamma-ray data with catalogs of objects with well-determined redshifts and positions. In this work, we cross-correlate Fermi-LAT skymaps with the 2MPZ catalog to study the local $z<0.2$ gamma-ray Universe, where about ten percent of the total unresolved gamma-ray background is produced. We find the signal to be dominated by AGN emissions, while star forming galaxies provide a subdominant contribution. Possible hints for a particle DM signal are discussed.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2018)·31 citations
27. 27*

    Vortex mass in the three-dimensional $O(2)$ scalar theory

    Gesualdo Delfino🇮🇹 · Walter Selke🇩🇪 · Alessio Squarcini🇩🇪

    We study the spontaneously broken phase of the $XY$ model in three dimensions, with boundary conditions enforcing the presence of a vortex line. Comparing Monte Carlo and field theoretic determinations of the magnetization and energy density profiles, we numerically determine the mass of the vortex particle in the underlying $O(2)$-invariant quantum field theory. The result shows, in particular, that the obstruction posed by Derrick's theorem to the existence of stable topological particles in scalar theories in more than two dimensions does not in general persist beyond the classical level.

    ↳ cond-mat.stat-mechcond-mat.supr-conhep-lathep-ph+1PRL(2019)·21 citations
28. 28*

    Model-independent Test of the Cosmic Distance Duality Relation

    Cheng-Zong Ruan🇨🇳 · Fulvio Melia🇺🇸 · Tong-Jie Zhang🇨🇳

    A validation of the cosmic distance duality (CDD) relation, eta(z)=(1+z)^2 d_A(z)/d_L(z)=1, coupling the luminosity (d_L) and angular-diameter (d_A) distances, is crucial because its violation would require exotic new physics. We present a model-independent test of the CDD, based on strong lensing and a reconstruction of the HII galaxy Hubble diagram using Gaussian Processes, to confirm the validity of the CDD at a very high level of confidence. Using parameterizations eta(z) = 1 + eta_0 z and eta(z) = 1 + eta_1 z + eta_2 z^2, our best-fit results are eta_0 = 0.0147^{+0.056}_{-0.066}, and eta_1 = 0.1091^{+0.1680}_{-0.1568} and eta_2 = -0.0603^{+0.0999}_{-0.0988}, respectively. In spite of these strong constraints, however, we also point out that the analysis of strong lensing using a simplified single isothermal sphere (SIS) model for the lens produces some irreducible scatter in the inferred CDD data. The use of an extended SIS approximation, with a power-law density structure, yields very similar results, but does not lessen the scatter due to its larger number of free parameters, which weakens the best-fit constraints. Future work with these strong lenses should therefore be based on more detailed ray-tracing calculations to determine the mass distribution more precisely.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phApJ(2018)·43 citations
29. 29*

    Inducing Gravity From Connections and Scalar Fields

    Hemza Azri🇹🇷

    We propose an approach to induced gravity, or Sakharov's "metrical elasticity", which requires only an affine spacetime that accommodates scalar fields. The setup provides the induction of metric gravity from a "pure affine" action, and it is established in two possible ways: (i) at the classical level, Einstein-Hilbert action arises with both, metric and Newton's constant, from the nonzero potential energy of the background field (ii) at the quantum level (quantized matter), gravity scale is induced from the one-loop effective action by integrating out the scalar degrees of freedom. In the former, the cosmological constant is absorbed leading to the gravitational sector, however, the fact remains that quantum corrections induce a large cosmological constant. This new approach adds a crucial feature to induced gravity which is the fact that the metric structure is not imposed from the scratch, but it is an outcome of the primary theory.

    ↳ gr-qchep-phhep-thClass.Quant.Grav.(2019)·12 citations
30. 30*

    Nonlinear Dynamics of Coupled Axion-Josephson Junction Systems

    Jin Yan🇬🇧 · Christian Beck🇬🇧

    We study the classical dynamics of an axion field (the signal) that is coupling into a Josephson junction (the detector) by means of a capacitive coupling of arbitrary size. Depending on the size of the coupling constant and the initial conditions, we find a rich phase space structure of this nonlinear problem. We present general analytic solutions of the equations of motion in the limit of small amplitudes of the angle variables, and discuss both the case of no dissipation and the case of dissipation in the system. The effect of a magnetic field is investigated as well, leading to topological phase transitions in the phase space structure.

    ↳ nlin.CDhep-phPhysica D: Nonlinear Phenomena(2020)·4 citations
31. 31*

    de Sitter Vacua with a Nilpotent Superfield

    Renata Kallosh🇺🇸 · Andrei Linde🇺🇸 · Evan McDonough🇺🇸 · Marco Scalisi🇧🇪

    We study the arguments given in [1] which suggest that the uplifting procedure in the KKLT construction is not valid. First we show that the modification of the SUSY breaking sector of the nilpotent superfield, as proposed in [1], is not consistent with non-linearly realized local supersymmetry of de Sitter supergravity. Keeping this issue aside, we also show that the corresponding bosonic potential does actually describe de Sitter uplifting.

    ↳ hep-thastro-ph.COgr-qchep-phFortsch.Phys.(2019)·49 citations
32. 32*

    A Precise Milky Way Rotation Curve Model for an Accurate Galactocentric Distance

    Stacy McGaugh🇺🇸

    I provide a model rotation curve for the Milky Way that matches the details of the terminal velocity curve normalized to the Galactocentric distance $R_0=8.122$ kpc obtained by the GRAVITY collaboration and the corresponding circular speed of the LSR ${\Theta }_0=233.3$ km/s. The model provides a numerical representation of the azimuthally averaged radial run of the gravitational potential of each mass component of the Galaxy (bulge-bar, stellar disk, gas disk, and dark matter) as represented by the rotation curve of each. It provides precise estimates of quantities like the stellar mass of the Galaxy ($6.16\pm 0.31\times 10^{10}{\mathrm{M}}_{\odot }$) and the local density of dark matter (${\rho }_{DM}(R_0)=6.76_{-0.14}^{+0.08}\times 10^{-3}{\mathrm{M}}_{\odot }{\mathrm{pc}}^{-3}=0.257_{-0.005}^{+0.003}\mathrm{GeV}{\mathrm{cm}}^{-3}$). The dark matter density implied by the radial force is less than that found in many studies of the vertical force, perhaps indicating that the usual assumption of a spherical dark matter halo is no longer adequate.

    ↳ astro-ph.GAhep-phRes.Notes AAS(2018)·22 citations
33. 33*

    The landscape, the swampland and the era of precision cosmology

    Yashar Akrami🇳🇱 · Renata Kallosh🇺🇸 · Andrei Linde🇺🇸 · Valeri Vardanyan🇳🇱

    We review the advanced version of the KKLT construction and pure $d=4$ de Sitter supergravity, involving a nilpotent multiplet, with regard to various conjectures that de Sitter state cannot exist in string theory. We explain why we consider these conjectures problematic and not well motivated, and why the recently proposed alternative string theory models of dark energy, ignoring vacuum stabilization, are ruled out by cosmological observations at least at the $3\sigma$ level, i.e. with more than $99.7\%$ confidence.

    ↳ hep-thastro-ph.COgr-qchep-ph+2Fortsch.Phys.(2019)·274 citations
34. 34*

    Dark Monopoles and SL(2,Z) Duality

    John Terning🇺🇸 · Christopher B. Verhaaren🇺🇸

    We explore kinetic mixing between two Abelian gauge theories that have both electric and magnetic charges. When one of the photons becomes massive, novel effects arise in the low-energy effective theory, including the failure of Dirac charge quantization as particles from one sector obtain parametrically small couplings to the photon of the other. We maintain a manifest SL(2,Z) duality throughout our analysis, which is the diagonal subgroup of the dualities of the two un-mixed gauge theories.

    ↳ hep-thhep-phJHEP(2018)·33 citations
35. 35*

    Mass-dependence of pseudoscalar meson elastic form factors

    Muyang Chen🇨🇳 · Minghui Ding🇨🇳 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸

    A continuum approach to quark-antiquark bound-states is used to determine the electromagnetic form factors of pion-like mesons with masses $m_{0^{-}}/\mathrm{GeV}=0.14$, $0.47$, $0.69$, $0.83$ on a spacelike domain that extends to $Q^2\lesssim 10$GeV${}^2$. The results enable direct comparisons with contemporary lattice-QCD calculations of heavy-pion form factors at large values of momentum transfer and aid in understanding them. They also reveal, inter alia, that the form factor of the physical pion provides the best opportunity for verification of the factorised hard-scattering formula relevant to this class of exclusive processes and that this capacity diminishes steadily as the meson mass increases.

    ↳ nucl-thhep-lathep-phnucl-exPRD(2018)·56 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.