Wed·May 22, 2019Wednesday·May 22, 2019

1. 01*

   Anomalous dimensions of potential top-partners

   Diogo Buarque Franzosi🇸🇪 · Gabriele Ferretti🇸🇪

   We discuss anomalous dimensions of top-partner candidates in theories of Partial Compositeness. First, we revisit, confirm and extend the computation by DeGrand and Shamir of anomalous dimensions of fermionic trilinears. We present general results applicable to all matter representations and to composite operators of any allowed spin. We then ask the question of whether it is reasonable to expect some models to have composite operators of sufficiently large anomalous dimension to serve as top-partners. While this question can be answered conclusively only by lattice gauge theory, within perturbation theory we find that such values could well occur for some specific models. In the Appendix we collect a number of practical group theory results for fourth-order invariants of general interest in gauge theories with many irreducible representations of fermions.

   hep-phhep-latSciPost Phys.(2019)·37 citations
2. 02*

   Hadron Spectra Parameters within the Non-Extensive Approach

   Keming Shen🇭🇺 · Gergely Gábor Barnaföldi🇭🇺 · Tamás Sándor Biró🇭🇺

   We investigate how the non-extensive approach works in high-energy physics. Transverse momentum ($p_T$) spectra of several hadrons are fitted by various non-extensive momentum distributions and by the Boltzmann--Gibbs statistics.~It is shown that some non-extensive distributions can be transferred one into another.~We find explicit hadron mass and center-of-mass energy {scaling both in the temperature and in the non-extensive parameter, $q$,} in proton--proton and heavy-ion collisions. We find that the temperature depends linearly, but the Tsallis $q$ follows a logarithmic dependence on the collision energy in proton--proton collisions. In the nucleus--nucleus collisions, on~the other hand, $T$ and $q$ correlate linearly, as was predicted in our previous work.

   hep-phUniverse(2019)·24 citations
3. 03*

   Revisiting the new-physics interpretation of the $b\to c\tau \nu$ data

   Rui-Xiang Shi🇨🇳 · Li-Sheng Geng🇨🇳 · Benjamín Grinstein🇺🇸 · Sebastian Jäger🇬🇧 · Jorge Martin Camalich🇪🇸

   We revisit the status of the new-physics interpretations of the anomalies in semileptonic $B$ decays in light of the new data reported by Belle on the lepton-universality ratios $R_{D^{(\ast )}}$ using the semileptonic tag and on the longitudinal polarization of the $D^{\ast }$ in $B\to D^{\ast }\tau \nu$, $F_L^{D^{\ast }}$. The preferred solutions involve new left-handed currents or tensor contributions. Interpretations with pure right-handed currents are disfavored by the LHC data, while pure scalar models are disfavored by the upper limits derived either from the LHC or from the $B_c$ lifetime. The observable $F_L^{D^{\ast }}$ also gives an important constraint leading to the exclusion of large regions of parameter space. Finally, we investigate the sensitivity of different observables to the various scenarios and conclude that a measurement of the tau polarization in the decay mode $B\to D\tau \nu$ would effectively discriminate among them.

   hep-phhep-exJHEP(2019)·127 citations
4. 04*

   Stochastic Gravitational Waves from Inflaton Decays

   Da Huang🇵🇱 · Lu Yin🇹🇼

   Due to the universality of gravitational interactions, it is generally expected that a stochastic gravitational wave (GW) background could form during the reheating period when the inflaton perturbatively decays with the emission of gravitons. Previously, only models in which the inflaton dominantly decays into a pair of light scalar and/or fermion particles were considered in the literature. In the present paper, we focus on the cases with a vector particle pair in the final decay product. The differential decay rates for the three-body gravitational inflaton decays are presented for two typical couplings between the inflaton and vector fields, from which we predict their respective GW frequency spectra. It turns out that, similar to the scalar and fermion cases, the obtained GW spectra is too high in frequency to be observed by the current and near-future GW detection experiments and calls for a new design of high-frequency GW detectors.

   hep-phastro-ph.COgr-qcPRD(2019)·51 citations
5. 05*

   Isolated photon and photon+jet production at NNLO QCD accuracy and the ratio $R_{13/8}^{\gamma }$

   X. Chen🇨🇭 · T. Gehrmann🇨🇭 · N. Glover🇬🇧 · M. Höfer🇨🇭 · A. Huss🇨🇭

   We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of $R_{13/8}^{\gamma }$, the ratio of the inclusive isolated photon cross section at 8 TeV and 13 TeV, differential in the photon transverse momentum, which was recently measured by the ATLAS collaboration.

   hep-phhep-ex4 citations
6. 06*

   $P_c(4457{)}^{+}$, $P_c(4440{)}^{+}$, and $P_c(4312{)}^{+}$: molecules or compact pentaquarks?

   Jian-Bo Cheng🇨🇳 · Yan-Rui Liu🇨🇳

   In a chromomagnetic model, we analyse the properties of the newly observed $P_c(4457{)}^{+}$, $P_c(4440{)}^{+}$, and $P_c(4312{)}^{+}$ states. We estimate the masses of the $(uud{)}_{8_c}(c\bar{c}{)}_{8_c}$ and $(uds{)}_{8_c}(c\bar{c}{)}_{8_c}$ pentaquark states by considering the isospin breaking effects. Their values are determined by calculating mass distances from the ${\Sigma }_c^{++}{D}^{-}$ and ${\Xi }_c^{\prime +}{D}^{-}$ thresholds, respectively. It is found that the isospin breaking effects on the spectrum are small. From the uncertainty consideration and the rearrangement decay properties in a simple model, we find that it is possible to assign the $P_c(4457{)}^{+}$, $P_c(4440{)}^{+}$, and $P_c(4312{)}^{+}$ as $J^P=3/2^{-}$, $1/2^{-}$, and $3/2^{-}$ pentaquark states, respectively. The assignment in the molecule picture can be different, in particular for the $P_c(4312{)}^{+}$. The information from open-charm channels, e.g. $\mathcal{B}[P_c\to {\Sigma }_c^{++}{D}^{-}]/\mathcal{B}[P_c\to J/\psi p]$, will play an important role in distinguishing the inner structures of the $P_c$ states. Discussions and predictions based on the calculations are also given.

   hep-phhep-exhep-latnucl-thPRD(2019)·106 citations
7. 07*

   Sum rules and asymptotic behaviors of neutrino mixing in dense matter

   Zhi-zhong Xing🇨🇳 · Jing-yu Zhu🇨🇳

   It has proved convenient to define the effective lepton flavor mixing matrix $\tilde{U}$ and neutrino mass-squared differences ${\tilde{\Delta }}_{ji}^{}\equiv {\tilde{m}}_j^2-{\tilde{m}}_i^2$ (for $i,j=1,2,3$) to describe the phenomena of neutrino mixing and flavor oscillations in a medium, but the prerequisite is to establish direct and transparent relations between these effective quantities and their fundamental counterparts in vacuum. With the help of two sets of sum rules for $\tilde{U}$ and ${\tilde{\Delta }}_{ji}^{}$, we derive new and exact formulas for moduli of the nine elements of $\tilde{U}$ and the sides of its three Dirac unitarity triangles in the complex plane. The asymptotic behaviors of $|{\tilde{U}}_{\alpha i}^{}{|}^2$ and ${\tilde{\Delta }}_{ji}^{}$ (for $\alpha =e,\mu ,\tau$ and $i,j=1,2,3$) in very dense matter (namely, allowing the matter parameter $A=2\sqrt{2}{G}_{\mathrm{F}}^{}{N}_e^{}E$ to mathematically approach infinity) are analytically unraveled for the first time, and in this connection the confusion associated with the parameter redundancy of ${\tilde{\theta }}_{12}^{}$, ${\tilde{\theta }}_{13}^{}$, ${\tilde{\theta }}_{23}^{}$ and $\tilde{\delta }$ in the standard parametrization of $\tilde{U}$ is clarified.

   hep-phhep-exNPB(2019)·14 citations
8. 08*

   Semileptonic ${\Xi }_c$ baryon decays in the relativistic quark model

   R. N. Faustov🇷🇺 · V. O. Galkin🇷🇺

   The form factors of the weak ${\Xi }_c\to \Xi (\Lambda )$ transitions are calculated in the framework of the relativistic quark model based on the quasipotential approach. All relativistic effects including transformations of the baryon wave functions from the rest to moving reference frame and contributions of the intermediate negative energy states are systematically taken into account. The explicit analytic expressions which reliably approximate the momentum transfer $q^2$ dependence of the form factors in the whole accessible kinematical range are given. The calculated form factors are applied for the evaluation of the semileptonic ${\Xi }_c\to \Xi \ell {\nu }_{\ell }$ and ${\Xi }_c\to \Lambda \ell {\nu }_{\ell }$ ($\ell =e,\mu$) decay rates, different asymmetry and polarization parameters within helicity formalism. The obtained results are compared with available experimental data and previous calculations.

   hep-phhep-exEPJC(2019)·24 citations
9. 09*

   Mass and Life Time of Heavy Dark Matter Decaying into IceCube PeV Neutrinos

   Madhurima Pandey (Saha Inst.)🇮🇳 · Debasish Majumdar (Saha Inst.)🇮🇳 · Ashadul Halder🇮🇳 · Shibaji Banerjee🇮🇳

   Considering that the ultrahigh energy (UHE) upgoing muon neutrino events around the PeV energy region observed by the IceCube are due to the decay of super heavy dark matter to neutrinos, we constrain the mass of the decaying dark matter and its decay lifetime using the IceCube analysis of these neutrinos in the PeV region. The theoretical fluxes are computed by adpoting the procedure given in the reference [1,2], where the DGLAP numerical evolutions of QCD cascades as well as electroweak corrections are included for evolving the decay process of the super heavy dark matter. Our results indicate that to explain the IceCube events around PeV region the decaying dark matter mass $m_{\chi }$ would be $\sim 5\times 10^7$ GeV with the decay lifetime $\tau \sim 7\times 10^{28}$ sec.

   hep-phPLB(2019)·8 citations
10. 10*

    Parton branching at amplitude level

    Jeffrey R. Forshaw🇬🇧 · Jack Holguin🇬🇧 · Simon Plätzer🇦🇹

    We present an algorithm that evolves hard processes at the amplitude level by dressing them iteratively with (massless) quarks and gluons. The algorithm interleaves collinear emissions with soft emissions and includes Coulomb/Glauber exchanges. It includes all orders in $N_{\mathrm{c}}$, is spin dependent and is able to accommodate kinematic recoils. Although it is specified at leading logarithmic accuracy, the framework should be sufficient to go beyond. Coulomb exchanges make the factorisation of collinear and soft emissions highly non-trivial. In the absence of Coulomb exchanges, we show how factorisation works out and how a partial factorisation is manifest in the presence of Coulomb exchanges. Finally, we illustrate the use of the algorithm by deriving DGLAP evolution and computing the resummed thrust, hemisphere jet mass and gaps-between-jets distributions in $e^{+}{e}^{-}$.

    hep-phJHEP(2019)·95 citations
11. 11*

    General Neutrino Interactions from an Effective Field Theory Perspective

    Ingolf Bischer🇩🇪 · Werner Rodejohann🇩🇪

    General Neutrino Interactions (GNI) are scalar, pseudoscalar, vector, axial vector or tensor interactions of neutrinos with fermions, and generalise the often studied neutrino Non-Standard Interactions (NSI). If GNI arise from heavy new physics, they should be embeddable into effective field theory operators that respect the Standard Model (SM) gauge symmetry. Therefore we consider a full basis of gauge-invariant dimension-six operators involving SM fermions and right-handed singlet neutrinos and map their Wilson coefficients onto GNI parameters. In this embedding we discuss correlations of and bounds on different GNI in the context of charged lepton flavour violation processes and neutrino-fermion scattering, as well as beta decay and coherent neutrino-nucleus scattering. We also study possible UV completions of the relevant dimension-six operators for GNI via leptoquarks that can be related to radiative neutrino masses and $B$ physics anomalies. Details on the numbers of free GNI parameters for Dirac or Majorana neutrinos and for CP violation or conservation are also provided.

    hep-phNPB(2019)·151 citations
12. 12*

    Quark propagator in Minkowski space

    E. L. Solis🇧🇷 · C. S. R. Costa🇧🇷 · V. V. Luiz🇧🇷 · G. Krein🇧🇷

    The analytic structure of the quark propagator in Minkowski space is more complex than in Euclidean space due to the possible existence of poles and branch cuts at timelike momenta. These singularities impose enormous complications on the numerical treatment of the nonperturbative Dyson-Schwinger equation for the quark propagator. Here we discuss a computational method that avoids most of these complications. The method makes use of the spectral representation of the propagator and of its inverse. The use of spectral functions allows one to handle in exact manner poles and branch cuts in momentum integrals. We obtain model-independent integral equations for the spectral functions and perform their renormalization by employing a momentum-subtraction scheme. We discuss an algorithm for solving numerically the integral equations and present explicit calculations in a schematic model for the quark-gluon scattering kernel.

    hep-phFew Body Syst.(2019)·23 citations
13. 13*

    Next-to-leading power threshold effects for inclusive and exclusive processes with final state jets

    Melissa van Beekveld🇳🇱 · Wim Beenakker🇳🇱 · Eric Laenen🇳🇱 · Chris D. White🇬🇧

    It is well known that cross-sections in perturbative QCD receive large corrections from soft and collinear radiation, whose properties must be resummed to all orders in the coupling. Whether or not the universal properties of this radiation can be extended to next-to-leading power (NLP) in the threshold expansion has been the subject of much recent study. In this paper, we consider two types of NLP effects: the interplay of next-to-soft and collinear radiation in processes with final state jets and the NLP contributions stemming from soft quarks. We derive an NLP amplitude for soft gluons and quarks, valid for an arbitrary number of coloured or colourless massless final state particles. We show explicitly that this framework can be used to correctly obtain the dominant NLP effects in three different types of processes at next-to-leading order: deep-inelastic scattering, hadroproduction via electron-positron annihilation and prompt photon production. Our results provide an important ingredient for developing a universal resummation formalism for NLP effects.

    hep-phJHEP(2020)·49 citations
14. 14*

    Gluon propagator in two-color dense QCD: Massive Yang-Mills approach at one-loop

    Daiki Suenaga🇨🇳 · Toru Kojo🇨🇳

    We study the Landau gauge gluon propagators in dense two-color QCD at quark chemical potential, ${\mu }_q$, in the range from 0.5 to 1.0 GeV not reachable by the perturbative method at weak coupling. In order to take into account the non-perturbative effects, at tree level we use a massive Yang-Mills model for the Yang-Mills theory (or the Curci-Ferrari model) which has successfully described the lattice results of the gluon and ghost propagators in the Landau gauge. We couple quarks to this theory and compute the one-loop polarization effects in medium. The presence of the gluon mass significantly tempers the medium effects and uncertainties associated with the strong coupling constant ${\alpha }_s$. The diquark condensate in two-color QCD is color-singlet, for which neither electric nor magnetic screening masses should appear at the scale less than the diquark gap. The presence of the gap helps to explain the lattice results which are not very sensitive to the quark density. Meanwhile we also found the limitation of the one-loop estimate as well as the lack of some physics in perturbative medium corrections.

    hep-phastro-ph.HEhep-latnucl-thPRD(2019)·34 citations
15. 15*

    Flavor-changing hyperon decays with light invisible bosons

    Gang Li🇹🇼 · Jhih-Ying Su🇹🇼 · Jusak Tandean🇹🇼

    We consider the strangeness-changing decays of hyperons into another baryon and missing energy which is carried away by a pair of invisible spinless bosons. Pursuing a model-independent approach and taking into account constraints from the kaon sector, we find that these hyperon modes can have large rates, especially if the bosons have parity-odd effective couplings to light quarks. In that case the rates could attain values which are well within the expected reach of the currently running BESIII experiment. Since the branching fractions of hyperon decays with missing energy are tiny in the standard model, observing them at ongoing or upcoming facilities would likely be indicative of new physics. In addition, we show that the kaon restrictions may be weakened or absent if the bosons have nonnegligible mass. Specifically, if the bosons interact with the quarks solely via an axial-vector current, in the mass region from about 115 to 175 MeV the constraints from rare kaon decays no longer apply and a couple of the hyperon modes become the only direct probes of such interactions. We also make comparisons with the previously explored new-physics scenario where the invisible particles are spin-1/2 fermions.

    hep-phhep-exnucl-thPRD(2019)·12 citations
16. 16*

    $b\to c\tau \bar{\nu }$ decays in supersymmetry with $R$-parity violation

    Dong-Yang Wang🇨🇳 · Ya-Dong Yang🇨🇳 · Xing-Bo Yuan🇨🇳

    In the past few years, several hints of lepton flavour universality (LFU) violation have emerged in the $b\to c\tau \bar{\nu }$ and $b\to s{\ell }^{+}{\ell }^{-}$ data. Quite recently, the Belle Collaboration has reported the first measurement of the $D^{\ast }$ longitudinal polarization fraction in the $B\to D^{\ast }\tau \bar{\nu }$ decay. Motivated by this intriguing result, together with the recent measurements of $R_{J/\psi }$ and $\tau$ polarization, we study $b\to c\tau \bar{\nu }$ decays in the Supersymmetry (SUSY) with $R$-parity violation (RPV). We consider $B\to D^{(\ast )}\tau \bar{\nu }$, $B_c\to {\eta }_c\tau \bar{\nu }$, $B_c\to J/\psi \tau \bar{\nu }$ and ${\Lambda }_b\to {\Lambda }_c\tau \bar{\nu }$ modes and focus on the branching ratios, the LFU ratios, the forward-backward asymmetries, polarizations of daughter hadrons and $\tau$ lepton. It is found that the RPV SUSY can explain the $R_{D^{(\ast )}}$ anomalies at $2\sigma$ level, after taking into account various flavour constraints. In the allowed parameter space, the differential branching fractions and LFU ratios are largely enhanced by the SUSY effects, especially in the large dilepton invariant mass region. In addition, a lower bound $\mathcal{B}(B^{+}\to K^{+}\nu \bar{\nu })>7.37\times 10^{-6}$ is obtained. These observables could provide testable signatures at the High-Luminosity LHC and SuperKEKB, and correlate with direct searches for SUSY.

    hep-phCPC(2019)·12 citations
17. 17*

    A Predictive Mirror Twin Higgs with Small ${\mathbf{Z}}_2$ Breaking

    Keisuke Harigaya🇺🇸 · Robert McGehee🇺🇸 · Hitoshi Murayama🇺🇸 · Katelin Schutz🇺🇸

    The twin Higgs mechanism is a solution to the little hierarchy problem in which the top partner is neutral under the Standard Model (SM) gauge group. The simplest mirror twin Higgs (MTH) model -- where a ${\mathbf{Z}}_2$ symmetry copies each SM particle -- has too many relativistic degrees of freedom to be consistent with cosmological observations. We demonstrate that MTH models can have an observationally viable cosmology if the twin mass spectrum leads to twin neutrino decoupling before the SM and twin QCD phase transitions. Our solution requires the twin photon to have a mass of $\sim 20$ MeV and kinetically mix with the SM photon to mediate entropy transfer from the twin sector to the SM. This twin photon can be robustly discovered or excluded by future experiments. Additionally, the residual twin degrees of freedom present in the early Universe in this scenario would be detectable by future observations of the cosmic microwave background.

    hep-phastro-ph.COhep-exJHEP(2020)·51 citations
18. 18*

    The Thermal History of Composite Dark Matter

    Nicola Andrea Dondi🇩🇰 · Francesco Sannino🇩🇰 · Juri Smirnov🇩🇰

    We study the thermodynamic history of composite Dark Matter models. We start with classifying the models by means of the symmetries partially protecting the composite Dark Matter decays and constrain their lifetimes. For each model, we determine the impact of number-changing and number-conserving operators on its thermal history. We also develop the analytic formalism to calculate the asymptotic abundance of stable relics. We show how the relative strength between number-changing and number-conserving interactions together with the dark plasma lifetime affect the thermal fate of the various composite models. Additionally, we discover that the final dark relic density of composite particles can be diluted due to an entropy increase stemming from dark plasma decay. Finally, we confront the models with experimental bounds. We find that indirect detection experiments are most promising in testing this large class of models.

    hep-phastro-ph.HEPRD(2020)·43 citations
19. 19*

    Sterile neutrino dark matter via GeV-scale leptogenesis?

    J. Ghiglieri🇨🇭 · M. Laine🇨🇭

    It has been proposed that in a part of the parameter space of the Standard Model completed by three generations of keV...GeV right-handed neutrinos, neutrino masses, dark matter, and baryon asymmetry can be accounted for simultaneously. Here we numerically solve the evolution equations describing the cosmology of this scenario in a 1+2 flavour situation at temperatures $T\le 5$ GeV, taking as initial conditions maximal lepton asymmetries produced dynamically at higher temperatures, and accounting for late entropy and lepton asymmetry production as the heavy flavours fall out of equilibrium and decay. For 7 keV dark matter mass and other parameters tuned favourably, $\sim 10\%$ of the observed abundance can be generated. Possibilities for increasing the abundance are enumerated.

    hep-phJHEP(2019)·39 citations
20. 20*

    To Positivity and Beyond, where Higgs-Dilaton Inflation has never gone before

    Mario Herrero-Valea🇨🇭 · Inar Timiryasov🇨🇭 · Anna Tokareva🇷🇺

    We study the consequences of (beyond) positivity of scattering amplitudes in the effective field theory description of the Higgs-Dilaton inflationary model. By requiring the EFT to be compatible with a unitary, causal, local and Lorentz invariant UV completion, we derive constraints on the Wilson coefficients of the first higher order derivative operators. We show that the values allowed by the constraints are consistent with the phenomenological applications of the Higgs-Dilaton model.

    hep-phgr-qchep-thJCAP(2019)·56 citations
21. 21*

    Non-Abelian basis tensor gauge theory

    Edward E. Basso🇺🇸 · Daniel J. H. Chung🇺🇸

    Basis tensor gauge theory is a vierbein analog reformulation of ordinary gauge theories in which the difference of local field degrees of freedom has the interpretation of an object similar to a Wilson line. Here we present a non-Abelian basis tensor gauge theory formalism. Unlike in the Abelian case, the map between the ordinary gauge field and the basis tensor gauge field is nonlinear. To test the formalism, we compute the beta function and the two-point function at the one-loop level in non-Abelian basis tensor gauge theory and show that it reproduces the well-known results from the usual formulation of non-Abelian gauge theory.

    ↳ hep-thastro-ph.HEhep-phPRD(2019)·1 citation
22. 22*

    Pulsar tests of the gravitational Lorentz violation

    Lijing Shao🇨🇳

    Pulsars are precision celestial clocks. When being put in a binary, the ticking conveys the secret of underlying spacetime geometrodynamics. We use pulsars to test if the gravitational interaction possesses a tiny deviation from Einstein's General Relativity (GR). In the framework of Standard-Model Extension (SME), we systematically search for Lorentz-violating operators cataloged by (a) the minimal couplings of mass dimension 4, (b) the CPT symmetry of mass dimension 5, and (c) the gravitational weak equivalence principle (GWEP) of mass dimension 8. No deviation from GR was found yet.

    ↳ gr-qcastro-ph.HEhep-phProceedings of the Eighth Meeting on CPT …·3 citations
23. 23*

    Violation of the equivalence principle from light scalar fields: from Dark Matter candidates to scalarized black holes

    A. Hees🇫🇷 · O. Minazzoli🇲🇨 · E. Savalle🇫🇷 · Y. V. Stadnik🇩🇪 · P. Wolf🇫🇷 · B. Roberts🇫🇷

    Tensor-scalar theory is a wide class of alternative theory of gravitation that can be motivated by higher dimensional theories, by models of dark matter or dark ernergy. In the general case, the scalar field will couple non-universally to matter producing a violation of the equivalence principle. In this communication, we review a microscopic model of scalar/matter coupling and its observable consequences in terms of universality of free fall, of frequencies comparison and of redshifts tests. We then focus on two models: (i) a model of ultralight scalar dark matter and (ii) a model of scalarized black hole in our Galactic Center. For both these models, we present constraints using recent measurements: atomic clocks comparisons, universality of free fall measurements, measurement of the relativistic redshift with the short period star S0-2 orbiting the supermassive black hole in our Galactic Center.

    ↳ gr-qcastro-ph.GAhep-ph13 citations
24. 24*

    Implementation of the SuSAv2-MEC 1p1h and 2p2h models in GENIE and analysis of nuclear effects in T2K measurements

    Stephen Dolan🇫🇷 · Guillermo Megias🇯🇵 · Sara Bolognesi🇫🇷

    We first present the implementation and validation of the SuSAv2-MEC 1p1h and 2p2h models in the GENIE neutrino-nucleus interaction event generator and a comparison of the subsequent predictions to measurements of lepton and hadron kinematics from the T2K experiment. These predictions are also compared to those of other available models in GENIE. We additionally compare the semi-inclusive predictions of the implemented 1p1h model to those of the microscopic model on which SuSAv2 is based - Relativistic Mean Field (RMF) - to begin to test the validity of widely-used `factorisation' assumptions employed by generators to predict hadron kinematics from inclusive input models. The results highlight that a more precise treatment of hadron kinematics in generators is essential in order to attain the few-% level uncertainty on neutrino interactions necessary for the next generation of accelerator-based long-baseline neutrino oscillation experiments.

    ↳ hep-exhep-phPRD(2020)·102 citations
25. 25*

    Spin correlations in top physics at ATLAS and CMS in Run 2

    Jacob Linacre (on behalf of the ATLAS and CMS Collaborations)🇬🇧

    Measurements of $\mathrm{t}\bar{\mathrm{t}}$ spin correlations are presented in events with top quarks produced in $\mathrm{pp}$ collisions at the LHC. The data correspond to an integrated luminosity of $36\mathrm{f}{\mathrm{b}}^{-1}$ at $\sqrt{s}=13\mathrm{TeV}$ collected at both the ATLAS and CMS detectors. The spin correlations are measured using the angular distributions of the leptons in dilepton channel $\mathrm{t}\bar{\mathrm{t}}$ events. The spin correlations are probed both directly, using distributions measured in the top quark rest frames that depend only on the top quark spin, and indirectly, using distributions measured in the laboratory frame. The distributions are unfolded to the parton level and extrapolated to the full phase space. Some of the laboratory frame distributions are additionally unfolded to the particle level in the fiducial phase space of the ATLAS detector. The spin correlation measurements are used to search for new physics in the form of a light top squark or an anomalous top quark chromo-magnetic dipole moment, and stringent constraints are placed in both cases.

    ↳ hep-exhep-ph2 citations
26. 26*

    A critical look at $\beta$-function singularities at large $N$

    Tommi Alanne🇩🇪 · Simone Blasi🇩🇪 · Nicola Andrea Dondi🇩🇰

    We propose a self-consistency equation for the $\beta$-function for theories with a large number of flavours, $N$, that exploits all the available information in the Wilson-Fisher critical exponent, $\omega$, truncated at a fixed order in $1/N$. We show that singularities appearing in critical exponents do not necessarily imply singularities in the $\beta$-function. We apply our method to (non-)abelian gauge theory, where $\omega$ features a negative singularity. The singularities in the $\beta$-function and in the fermion mass anomalous dimension are simultaneously removed providing no hint for a UV fixed point in the large-$N$ limit.

    ↳ hep-thhep-phPRL(2019)·19 citations
27. 27*

    Gravitational Instability of Exotic Compact Objects

    Andrea Addazi🇨🇳 · Antonino Marciano🇨🇳 · Nicolas Yunes🇺🇸

    Exotic compact objects with physical surfaces a Planckian distance away from where the horizon would have been are inspired in quantum gravity. Most of these objects are defined by a classical spacetime metric, such as boson stars, gravastars and wormholes. We show that these classical objects are gravitationally unstable because accretion of ordinary and dark matter, and gravitational waves forces them to collapse to a black hole by the Hoop conjecture. To avoid collapse, their surface must be a macroscopic distance away from the horizon or they must violate the null energy condition.

    ↳ gr-qchep-phhep-thEPJC(2020)·26 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.