Tue·Dec 10, 2019Tuesday·December 10, 2019

1. 01*

   Probing dark matter and quantum field theory effects with Rydberg atoms

   A. Capolupo🇮🇹 · S. M. Giampaolo🇭🇷 · G. Lambiase🇮🇹 · A. Quaranta🇮🇹

   We analyze the oscillations of Rydberg atoms in the framework of quantum field theory and we reveal non-trivial vacuum energy which has the equation of state of the dark matter. This energy is similar to that expected for mixed neutrinos and affects the thermal capacity of the gas. Therefore, the deflection of the thermal capacity of Rydberg atoms could prove the condensate structure of vacuum for mixing fermions and open new scenarios in the study of the dark components of the universe.

   hep-phEPJC(2020)·27 citations
2. 02*

   Production of the (predicted) $K^{\ast }(4307)$ in $B$ decays

   Xiu-Lei Ren🇩🇪 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷

   In this work we study the production of $K^{\ast }(4307)$ in $B$ decays by determining the $J/\psi {\pi }^{+(0)}{K}^0$ and $J/\psi {\pi }^{-}{K}^{+}$ invariant mass distributions of the processes $B^{+}\to J/\psi {\pi }^{+}{\pi }^0{K}^0$ and $B^{+}\to J/\psi {\pi }^{+}{\pi }^{-}{K}^{+}$, respectively. Such $K^{\ast }(4307)$ has been recently predicted as a three-body state originated from the dynamics involved in the $KD{\bar{D}}^{\ast }$ system, with the $KD$ subsystem forming the $D_{s0}^{\ast }(2317)$ in isospin 0, and the $D{\bar{D}}^{\ast }$ subsystem generating the $X(3872)$ in isospin 0 and the $Z_c(3900)$ in isospin 1. The hidden charm content of $K^{\ast }(4307)$ favors its decay to a state like $J/\psi \pi K$ and the study of $B$-decays with these particles in their final states can constitute a way of finding experimental evidences for such an exotic vector meson, whose width, in spite of its large mass, is still quite narrow (around 18 MeV).

   hep-phnucl-thPRD(2020)·8 citations
3. 03*

   Contributions of box diagrams and $\Delta (1940)$ resonance to $K^0{\Sigma }^{+}$ photoproduction

   Xuyang Liu🇨🇳 · Daris Samart🇹🇭 · Kai Xu🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭 · Qiang Zhao🇨🇳

   We study first the box-diagram contribution to the $\gamma p\to K^0{\Sigma }^{+}$ process to understand the anomaly of the kaon photoproduction cross section from CBELSA/TAPS experiment at Electron Stretcher Accelerator (ELSA), where the imaginary part of the scattering amplitude from the box-diagrams is calculated by using Cutkosky's rules in the on-shell approximation while the real part of the amplitude is derived by dispersion relation calculations. Together with the results of the K-MAID model, the contribution of the box-diagrams fails to provide the sudden drop of the differential cross-section between the $K^{\ast }\Lambda$ and $K^{\ast }\Sigma$ thresholds. In addition, we include the $\Delta (1940)$ resonance in the process to complete the description of the differential cross-section. Combining the contributions from the K-MAID model, the box-diagrams and the $\Delta (1940)$ resonance, we have obtained the theoretical differential cross-section the $\gamma p\to K^0{\Sigma }^{+}$ process, which is compatible with the CBELSA/TAPS experimental data.

   hep-phnucl-th1 citation
4. 04*

   Improving Heavy Dijet Resonance Searches Using Jet Substructure at the LHC

   Aruna Kumar Nayak🇮🇳 · Santosh Kumar Rai🇮🇳 · Tousik Samui🇮🇳

   The search for new physics at high energy accelerators has been at the crossroads with very little hint of signals suggesting otherwise. The challenges at a hadronic machine such as the LHC is compounded by the fact that final states are swamped with jets which one needs to understand and unravel. A positive step in this direction would be to separate the jets in terms of their gluonic and quark identities, much in a similar spirit of distinguishing heavy quark jets from light quark jets that has helped in improving searches for both neutral and charged Higgs bosons at the LHC. In this work, we utilise this information using the jet substructure techniques to comment on possible improvements in sensitivity as well as discrimination of new resonances in the all hadronic mode that would be crucial in pinning down new physics signals at HL-LHC, HE-LHC and any future 100 TeV hadron collider.

   hep-phhep-exEPJC(2021)·4 citations
5. 05*

   Extended Projection Method for Massive Fermion

   Yefan Wang🇨🇳 · Zhao Li🇨🇳

   Tensor reduction is important for multi-loop amplitude calculation. And the projection method is one of the most popular approaches for tensor reduction. However, projection method could be problematic for amplitude with massive fermions due to the inconsistency between helicity and chirality. We propose an approach to extend the projection method to reduce the loop amplitude containing fermion chain with two massive spinors. The extension is achieved by decomposing one of the massive spinors into two specific massless spinors, "null spinor" and "reference spinor". Then the extended projection method can be safely implemented for all the processes including the production of massive fermions. Finally we present the tensor reduction for the virtual Z boson decaying to top-quark pair to demonstrate our approach.

   hep-phCPC(2020)·1 citation
6. 06*

   NNLO QCD Corrections for Higgs-plus-jet Production in the Four-lepton Decay Mode

   Xuan Chen🇨🇭 · Thomas Gehrmann🇨🇭 · Nigel Glover🇬🇧 · Alexander Huss🇨🇭

   We present the computation of Higgs boson production in association with a jet at the LHC including QCD corrections up to NNLO. The calculation includes the subsequent decay of the Higgs boson into four leptons, allowing for the full reconstruction of the final-state kinematics. In anticipation of improved LHC measurements based on the full Run II dataset, we present a study for single- and double-differential cross sections within the fiducial volume as defined in prior ATLAS analyses. Higher-order corrections are found to have a sizeable impact on both normalisation and shape of differential cross sections.

   hep-phPoS(2019)·0 citations
7. 07*

   Light-quark components analysis and the nature of the $Y(4260)$

   Yun-Hua Chen🇨🇳 · Ling-Yun Dai🇨🇳 · Feng-Kun Guo🇨🇳 · Bastian Kubis🇩🇪

   We study the processes $e^{+}{e}^{-}\to Y(4260)\to J/\psi \pi \pi (K\bar{K})$. The strong final-state interactions, especially the coupled-channel ($\pi \pi$ and $K\bar{K}$) final-state interaction in the $S$-wave are taken into account in a model-independent way using dispersion theory. It is found that the light-quark SU(3) octet state plays a significant role in these transitions, implying that the $Y(4260)$ contains a large light-quark component. Our findings suggest that the $Y(4260)$ is neither a hybrid nor a conventional charmonium state. Furthermore, through an analysis of the ratio of the light-quark SU(3) octet and singlet components, we show that the $Y(4260)$ does not behave like a pure $\bar{D}{D}_1$ hadronic molecule as well.

   hep-phhep-ex0 citations
8. 08*

   Explaining $b\to s{\ell }^{+}{\ell }^{-}$ data by sneutrinos in the $R$-parity violating MSSM

   Quan-Yi Hu🇨🇳 · Lin-Lin Huang🇨🇳

   The recent measurements on $b\to s{\ell }^{+}{\ell }^{-}$ processes suggest the existence of lepton-flavour-universality breaking new physics. In this work, we have explored the possibility of explaining these data by sneutrinos in the $R$-parity violating minimal supersymmetric standard model. We study the light sneutrinos, of order 1 TeV, and suppose that the rest of the sfermions are much heavier than them. This setup can solve the $b\to s{\mu }^{+}{\mu }^{-}$ anomaly well, and it is almost unconstrained by other related processes, such as $B_s-{\bar{B}}_s$ mixing, as well as $B_s^0\to {\tau }^{+}{\tau }^{-}$, $B^{+}\to K^{+}{\tau }^{+}{\tau }^{-}$, $B_s^0\to {\tau }^{\pm }{\mu }^{\mp }$, $B^{+}\to K^{+}{\tau }^{\pm }{\mu }^{\mp }$, and $B\to K^{(\ast )}\nu \bar{\nu }$ decays.

   hep-phPRD(2020)·29 citations
9. 09*

   Probing the scale of grand unification with gravitational waves

   Wilfried Buchmuller🇩🇪 · Valerie Domcke🇩🇪 · Hitoshi Murayama🇺🇸 · Kai Schmitz🇨🇭

   The spontaneous breaking of U(1)_B-L around the scale of grand unification can simultaneously account for hybrid inflation, leptogenesis, and neutralino dark matter, thus resolving three major puzzles of particle physics and cosmology in a single predictive framework. The B-L phase transition also results in a network of cosmic strings. If strong and electroweak interactions are unified in an SO(10) gauge group, containing U(1)_B-L as a subgroup, these strings are metastable. In this case, they produce a stochastic background of gravitational waves that evades current pulsar timing bounds, but features a flat spectrum with amplitude h^2\Omega_GW ~ 10^-8 at interferometer frequencies. Ongoing and future LIGO observations will hence probe the scale of B-L breaking.

   hep-phastro-ph.COgr-qcPLB(2020)·131 citations
10. 10*

    Search for the SUSY Electroweak Sector at $ep$ Colliders

    Georges Azuelos🇨🇦 · Monica D'Onofrio🇬🇧 · Sho Iwamoto🇮🇹 · Kechen Wang🇨🇳

    The sensitivity of future electron-proton colliders, the LHeC and FCC-eh, to weakly-produced supersymmetric particles is evaluated in this article. Supersymmetric scenarios where charginos (${\tilde{\chi }}_1^{\pm }$) and neutralinos (${\tilde{\chi }}_1^0$ and ${\tilde{\chi }}_2^0$) are nearly degenerate in mass are considered. Two sets of models, which differ in the mass of sleptons ($\tilde{\ell }$), are studied. Under the hypothesis that slepton masses are at the multi-TeV scale (``decoupled'' scenario), the production processes for charginos and neutralinos at $ep$ colliders, $p{e}^{-}\to j{e}^{-}\tilde{\chi }\tilde{\chi }$ with $\tilde{\chi }={\tilde{\chi }}_1^0$, ${\tilde{\chi }}_1^{\pm }$ or ${\tilde{\chi }}_2^0$, are considered. For the models where slepton masses are above but close to ${\tilde{\chi }}_1^{\pm }$, ${\tilde{\chi }}_2^0$ masses (``compressed'' scenario), contributions from the processes $p{e}^{-}\to j\tilde{\chi }{\tilde{e}}_L^{-}$ and $j\tilde{\chi }\tilde{\nu }$ followed by the decays ${\tilde{e}}_L^{-}\to {\tilde{\chi }}_{1,2}^0+e^{-}$ and $\tilde{\nu }\to {\tilde{\chi }}_1^{+}+e^{-}$ are also taken into account. These scenarios are analysed with realistic detector performance, using multivariate techniques. Effects of systematic uncertainties and electron beam polarization dependence are also discussed. The reach is found to be complementary to the one obtained at $pp$ colliders, in particular for the compressed-slepton scenario.

    hep-phhep-exPRD(2020)·9 citations
11. 11*

    Angular analysis of $\bar{B}\to D_2^{\ast }(\to D\pi )\ell \bar{\nu }$ decay and new physics

    Rusa Mandal🇩🇪

    We derive the four-fold angular distribution for the semileptonic decay $\bar{B}\to D_2^{\ast }(\to D\pi )\ell \bar{\nu }$ where $D_2^{\ast }$(2460) is a tensor meson. We start with the most general beyond the Standard Model (SM) dimension-six effective Hamiltonian which comprises (axial)vector, (pseudo)scalar and tensor operators for both quark and lepton currents, and it also includes the right-handed neutrinos. The decay can be described by 16 transversity amplitudes and it provides a multitude of observables which can be extracted from data. We investigate the observables in the context of the SM and the new physics scenarios which can explain the intriguing discrepancies observed in the $b\to c\tau \bar{\nu }$ data.

    hep-phhep-exPRD(2020)·7 citations
12. 12*

    The proton radius: From a puzzle to precision

    Hans-Werner Hammer🇩🇪 · Ulf-G. Meißner🇩🇪

    We comment on the status and history of the proton charge radius determinations.

    hep-phhep-exhep-latnucl-ex+1Sci.Bull.(2020)·59 citations
13. 13*

    Prospects for detecting $SU(2{)}_L$ hidden sector bosons at ILC

    D.T. Binh🇻🇳 · H.N. Long🇻🇳

    We investigate the possibility of detecting hidden vector gauge bosons at ILC linear collider. The study is performed in the framework of hidden sector extension of Standard Model with 3 degenerate dark gauge bosons. By studying the cross section of pair dark gauge boson with photon at initial state radiation we found that at the energy $\sqrt{s}\approx$ 1300 GeV the cross section can be as large as $48fb$, the same order ($\mathcal{O}(fb)$) with the irreducible background of the Standard Model. Hence more methods needed to be done to eliminate the background for this model.

    hep-ph0 citations
14. 14*

    Impact of Electroweak Corrections on Neutral Higgs Boson Decays in Extended Higgs Sectors

    M. Krause🇩🇪 · M. Muhlleitner🇩🇪

    Precision predictions play an important role in the search for indirect New Physics effects in the Higgs sector itself. For the electroweak (EW) corrections of the Higgs bosons in extended Higgs sectors several renormalization schemes have been worked out that provide gauge-parameter-independent relations between the input parameters and the computed observables. Our recently published program codes 2HDECAY and ewN2HDECAY allow for the computation of the EW corrections to the Higgs decay widths and branching ratios of the Two-Higgs-Doublet Model (2HDM) and the Next-to-Minimal-2HDM (N2HDM) for different renormalization schemes of the scalar mixing angles. In this paper, we present a comprehensive and complete overview over the relative size of the EW corrections to the branching ratios of the 2HDM and N2HDM neutral Higgs bosons for different applied renormalization schemes. We quantify the size of the EW corrections of Standard Model(SM)- and non-SM-like Higgs bosons and moreover also identify renormalization schemes that are well-behaved and do not induce unnaturally large corrections. We furthermore pin down decays and parameter regions that feature large EW corrections and need further treatment in order to improve the predictions. Our study sets the scene for future work in the computation of higher-order corrections to the decays of non-minimal Higgs sectors.

    hep-phJHEP(2020)·20 citations
15. 15*

    Semileptonic decays $B/B_s\to (D^{(\ast )},D_s^{(\ast )})l{\nu }_l$ in the PQCD approach with the lattice QCD input

    Xue-Qing Hu🇨🇳 · Su-Ping Jin🇨🇳 · Zhen-Jun Xiao🇨🇳

    In this paper, we studied the semileptonic $B/B_s\to (D^{(\ast )},D_s^{(\ast )})l{\nu }_l$ decays in the framework of the standard model (SM) , by employing the perturbative QCD (PQCD) factorization formalism combining with the lattice QCD inputs of the relevant transition form factors. We calculated the branching ratios $\mathcal{B}(B_{(s)}\to D_{(s)}^{(\ast )}l{\nu }_l)$ with $l=(e,\mu .\tau )$ , the ratios of the branching ratios $R(D^{(\ast )})$ and $R(D_s^{(\ast )})$ and other physical observables $P_{\tau }(D_{(s)}^{(\ast )})$, $F_L(D_{(s)}^{\ast })$ and $A_{FB}(\tau )$. The "PQCD+Lattice" predictions for $\mathcal{B}(B\to D^{(\ast )}l{\nu }_l)$ and $R(D^{(\ast )})$ do agree well with those currently available experimental measurements within the errors. For the ratios $R(D_s)$ and $R(D_s^{\ast })$, the "PQCD+Lattice" predictions agree well with other known predictions. For both $P_{\tau }(D^{\ast })$ and $F_L(D^{\ast })$, our theoretical predictions agree well with the measured values within errors. Our theoretical predictions about the considered semileptonic $B/B_s$ decays could be tested in the near future LHCb and the Belle II experiments.

    hep-phhep-exCPC(2020)·33 citations
16. 16*

    Scotogenic neutrino mass with large $SU(2{)}_L$ multiplet fields

    Nilanjana Kumar🇮🇳 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇰🇷

    We construct a scotogenic neutrino mass model introducing large $SU(2{)}_L$ multiplet fields without adding an extra symmetry. We have introduced extra scalar fields such as a septet, quintet and quartet where we make the vacuum expectation value of quartet scalar to be zero while septet and quintet develop non-zero ones. Then the neutrino mass is generated at one-loop level by introducing quintet fermion. We analyze the neutrino mass matrix taking constraints from lepton flavor violation into account and discuss collider physics regarding charged fermions from large multiplet fields. We have analysed the production and the decays of the quintet fermions, as well as the discovery reach at 14 TeV and 27 TeV LHC.

    hep-phEPJC(2020)·12 citations
17. 17*

    Global fit of pseudo-Nambu-Goldstone Dark Matter

    Chiara Arina🇧🇪 · Ankit Beniwal🇧🇪 · Céline Degrande🇧🇪 · Jan Heisig🇧🇪 · Andre Scaffidi🇦🇺

    We perform a global fit within the pseudo-Nambu-Goldstone dark matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U(1) symmetry. Leading to a momentum-suppressed DM-nucleon cross section at tree level, the model provides a natural explanation for the null results from direct detection experiments. Our global fit combines constraints from perturbative unitarity, DM relic abundance, Higgs invisible decay, electroweak precision observables and latest Higgs searches at colliders. The results are presented in both frequentist and Bayesian statistical frameworks. Furthermore, post-processing our samples, we include the likelihood from gamma-ray observations of $Fermi$-LAT dwarf spheroidal galaxies and compute the one-loop DM-nucleon cross section. We find two favoured regions characterised by their dominant annihilation channel: the Higgs funnel and annihilation into Higgs pairs. Both are compatible with current $Fermi$-LAT observations, and furthermore, can fit the slight excess observed in four dwarfs in a mass range between about 30-300 GeV. While the former region is hard to probe experimentally, the latter can partly be tested by current observations of cosmic-ray antiprotons as well as future gamma-ray observations.

    hep-phastro-ph.COJHEP(2020)·52 citations
18. 18*

    Padé approach to top-quark mass effects in gluon fusion amplitudes

    Joshua Davies🇩🇪 · Ramona Gröber🇮🇹 · Andreas Maier🇩🇪 · Thomas Rauh🇨🇭 · Matthias Steinhauser🇩🇪

    Gluon fusion processes like single and double Higgs production exhibit slow convergence and pose severe computational challenges. We show how the top-quark mass dependence of the virtual amplitudes can be reconstructed with a conformal mapping and Padé approximants based on the expansion in the inverse top-quark mass and the non-analytic terms in the expansion around the top threshold. The method is then applied at two- and three-loop order.

    hep-phPoS(2019)·11 citations
19. 19*

    Entangled baryons: violation of Inequalities based on local realism assuming dependence of decays on hidden variables

    Yu Shi🇨🇳 · Ji-Chong Yang🇨🇳

    Bell inequalities are consequences of local realism while violated by quantum mechanics. In particle physics, entangled high energy particles can be produced from a common source, and the decay of each particle plays the role of measurement. However, in a hidden variable theory, the decay could be determined by hidden variables. This loophole killed such approaches to Bell test in particle physics. It is a special form of measurement-setting or free-will loophole, which also exists in other systems. Using entangled baryons, we present new inequalities of local realism with the explicit assumption of the dependence of the decays on hidden variables, as well as the consideration of the statistical mixture of polarizations and the separation of local hidden variables for objects with spacelike distances. These violations closes the measurement-setting loophole once and for all. We propose to use the processes ${\eta }_c\to \Lambda \bar{\Lambda }$ and ${\chi }_{c0}\to \Lambda \bar{\Lambda }$ to test our inequalities, and show that their violations are likely to be observed with the data already collected in BESIII.

    hep-phquant-phEPJC(2020)·19 citations
20. 20*

    Next-to-leading-order QCD and electroweak corrections to triple-W production with leptonic decays at the LHC

    Stefan Dittmaier🇩🇪 · Gernot Knippen🇩🇪 · Christopher Schwan🇮🇹

    We present a calculation of the next-to-leading-order QCD and electroweak corrections to WWW production with leptonically decaying $\mathrm{W}$ bosons at the LHC, fully taking into account off-shell contributions, intermediary resonances, and spin correlations. The contributions of the quark-antiquark-induced electroweak correction to typical fiducial cross sections at the LHC are of the order of 5-8% and grow to tens of percent in the high-energy tails of distributions. We observe strong cancellations among the positive quark-photon and negative quark-antiquark-induced electroweak corrections. In addition to results based on full $2\to 6/7$-particle next-to-leading-order matrix elements, we present a calculation based on the triple-pole approximation, which expands the matrix elements around the poles of three simultaneously resonant $\mathrm{W}$ bosons. The triple-pole approximation performs particularly well for integrated cross sections and for differential cross sections that are insensitive to off-shell effects, such as angular and rapidity distributions.

    hep-phJHEP(2020)·23 citations
21. 21*

    Hidden Sector and Gravity

    Xavier Calmet🇬🇧

    In this paper, we consider a generic hidden sector which interacts only gravitationally with Standard Model particles. We show that quantum gravity leads to operators which can be probed with fifth force type experiments. The Eöt-Wash torsion pendulum experiment implies that the masses of any scalar field or any massive spin-2 field that couples with the usual gravitational strength to the energy-momentum tensor of the Standard Model must be larger than $10^{-3}$eV. This has interesting consequences for models of dark matter which posit very light scalar fields. Dark matter must be heavier than $10^{-3}$eV if it is a scalar field or a massive spin-2 field.

    hep-phhep-thPLB(2020)·13 citations
22. 22*

    Bounds on non-standard interactions of neutrinos from IceCube DeepCore data

    S.V.Demidov🇷🇺

    New physics in neutrino sector can reveal itself via non-standard neutrino interactions which can result in modification of the standard picture of neutrino propagation in matter. Experiments with atmospheric neutrinos has been used to probe this scenario. Using publicly available three-year low energy data in IceCube DeepCore we place bounds on the parameters ${ϵ}_{\alpha \beta }$ of non-standard neutrino interactions in propagation. We obtain restrictive constraints not only for $\mu \tau$ sector but also for flavor changing interactions involving electron neutrinos.

    hep-phastro-ph.HEJHEP(2020)·11 citations
23. 23*

    Connection between $\nu n\to \bar{\nu }\bar{n}$ reactions and $n$-$\bar{n}$ oscillations via additional Higgs triplets

    Yongliang Hao🇳🇱

    In this work, we investigate the connection and compatibility between $\nu n\to \bar{\nu }\bar{n}$ reactions and $n$-$\bar{n}$ oscillations based on the $SU(3{)}_c\times SU(2{)}_L\times U(1)$ symmetry model with additional Higgs triplets. We explore the possibility that the scattering process $\nu n\to \bar{\nu }\bar{n}$ produced by low-energy solar neutrinos gives rise to an unavoidable background in the measurements of $n$-$\bar{n}$ oscillations. We focus on two different scenarios, depending on whether the $(B-L)$ symmetry could be broken. We analyze the interplay of the various constraints on the two processes and their observable consequences. In the scenario where both $(B+L)$ and $(B-L)$ could be broken, we point out that if all the constraints, mainly arising from the type-II seesaw mechanism, are satisfied, the parameter space would be severely constrained. In this case, although the masses of the Higgs triplet bosons could be within the reach of a direct detection at the LHC or future high-energy experiments, the predicted $n$-$\bar{n}$ oscillation times would be completely beyond the detectable regions of the present experiments. In both scenarios, the present experiments cannot distinguish a $\nu n\to \bar{\nu }\bar{n}$ reaction event from a $n$-$\bar{n}$ oscillation event within the accessible energy range. Nevertheless, if any of the two processes is detected, there could be signal associated with new physics beyond the Standard Model.

    hep-phastro-ph.HEPRD(2020)·3 citations
24. 24*

    Theoretical uncertainties in the MSSM Higgs boson mass calculation

    Henning Bahl🇩🇪 · Sven Heinemeyer🇪🇸 · Wolfgang Hollik🇩🇪 · Georg Weiglein🇩🇪

    The remaining theoretical uncertainties from unknown higher-order corrections in the prediction for the light Higgs-boson mass of the MSSM are estimated. The uncertainties associated with three different approaches that are implemented in the publicly available code FeynHiggs are compared: the fixed-order diagrammatic approach, suitable for low SUSY scales, the effective field theory (EFT) approach, suitable for high SUSY scales, and the hybrid approach which combines the fixed-order and the EFT approaches. It is demonstrated for a simple single-scale scenario that the result based on the hybrid approach yields a precise prediction for low, intermediate and high SUSY scales with a theoretical uncertainty of up to $\sim 1.5$ GeV for large stop mixing and $\sim 0.5$ GeV for small stop mixing. The uncertainty estimate of the hybrid calculation approaches the uncertainty estimate of the fixed-order result for low SUSY scales and the uncertainty estimate of the EFT approach for high SUSY scales, while for intermediate scales it is reduced compared to both of the individual results. The estimate of the theoretical uncertainty is also investigated in scenarios with more than one mass scale. A significantly enhanced uncertainty is found in scenarios where the gluino is substantially heavier than the scalar top quarks. The uncertainty estimate presented in this paper will be part of the public code FeynHiggs.

    hep-phEPJC(2020)·64 citations
25. 25*

    Particle Event Generator: A Simple-in-Use System PEGASUS version 1.0

    A.V. Lipatov🇷🇺 · M.A. Malyshev🇷🇺 · S.P. Baranov🇷🇺

    PEGASUS is a parton-level Monte-Carlo event generator designed to calculate cross sections for a wide range of hard QCD processes at high energy $pp$ and $p\bar{p}$ collisions, which incorporates the dynamics of transverse momentum dependent (TMD) parton distributions in a proton. Being supplemented with off-shell production amplitudes for a number of partonic subprocesses and provided with necessary TMD gluon density functions, it produces weighted or unweighted event records which can be saved as a plain data file or a file in a commonly used Les Houches Event format. A distinctive feature of PEGASUS is an intuitive and extremely user friendly interface, allowing one to easily implement various kinematical cuts into the calculations. Results can be also presented "on the fly" with built-in tool \textsc{pegasus plotter}. A short theoretical basis is presented and detailed program description is given.

    hep-phEPJC(2020)·37 citations
26. 26*

    Transferability of Deep Learning Models in Searches for New Physics at Colliders

    M. Crispim Romao🇵🇹 · N. F. Castro🇵🇹 · R. Pedro🇵🇹 · T. Vale🇵🇹

    In this work we assess the transferability of deep learning models to detect beyond the standard model signals. For this we trained Deep Neural Networks on three different signal models: $tZ$ production via a flavour changing neutral current, pair-production of vector-like $T$-quarks via standard model gluon fusion and via a heavy gluon decay in a grid of 3 mass points: 1, 1.2 and 1.4 TeV. These networks were trained with $t\bar{t}$, $Z$+jets and dibosons as the main backgrounds. Limits were derived for each signal benchmark using the inference of networks trained on each signal independently, so that we can quantify the degradation of their discriminative power across different signal processes. We determine that the limits are compatible within uncertainties for all networks trained on signals with vector-like $T$-quarks, whether they are produced via heavy gluon decay or standard model gluon fusion. The network trained on flavour changing neutral current signal, while struggling the most on the other signals, still produce reasonable limits. These results indicate that deep learning models are capable of providing sensitivity in the search for new physics even if it manifests itself in models not assumed during training.

    hep-phhep-exphysics.comp-phPRD(2020)·32 citations
27. 27*

    Flavor Phenomenology of the Leptoquark Singlet-Triplet Model

    Andreas Crivellin🇨🇭 · Dario Müller🇨🇭 · Francesco Saturnino🇨🇭

    In recent years, experiments revealed intriguing hints for new physics (NP) in semi-leptonic $B$ decays. Both in charged current processes, involving $b\to c\tau \nu$ transitions, and in the neutral currents $b\to s{\ell }^{+}{\ell }^{-}$, a preference for NP compared to the standard model (SM) of more that $3\sigma$ and $5\sigma$ was found, respectively. In addition, there is the long-standing tension between the theory prediction and the measurement of the anomalous magnetic moment (AMM) of the muon ($a_{\mu }$) of more than $3\sigma$. Since all these observables are related to the violation of lepton flavor universality (LFU), a common NP explanation seems not only plausible but is even desirable. In this context, leptoquarks (LQs) are especially promising since they give tree-level effects in semi-leptonic $B$ decays, but only loop-suppressed effects in other flavor observables that agree well with their SM predictions. Furthermore, LQs can lead to a $m_t/m_{\mu }$ enhanced effect in $a_{\mu }$, allowing for an explanation even with (multi) TeV particles. However, a single scalar LQ representation cannot provide a common solution to all three anomalies. In this article we therefore consider a model in which we combine two scalar LQs: the $SU(2{)}_L$ singlet and the $SU(2{)}_L$ triplet. Within this model we compute all relevant one-loop effects and perform a comprehensive phenomenological analysis, pointing out various interesting correlations among the observables. Furthermore, we identify benchmark points which are in fact able to explain all three anomalies ($b\to c\tau \nu$, $b\to s{\ell }^{+}{\ell }^{-}$ and $a_{\mu }$), without violating bounds from other observables, and study their predictions for future measurements.

    hep-phJHEP(2020)·188 citations
28. 28*

    Dark matter filtering-out effect during a first-order phase transition

    Dongjin Chway🇰🇷 · Tae Hyun Jung🇰🇷 · Chang Sub Shin🇰🇷

    If the mass of dark matter is generated from a cosmological phase transition involving the nucleation of bubbles, the corresponding bubble walls can filter out dark matter particles during the phase transition. Only particles with sufficient momentum to overcome their mass inside the bubbles can pass through the walls. As a result, the dark matter number density after the phase transition has a suppression factor $\exp (-M_{\chi }/2\tilde{\gamma }T)$, where $M_{\chi }$ is the dark matter mass, and $\tilde{\gamma }$ and $T$ are the Lorentz factor and temperature of the incoming fluid in the bubble wall rest frame, respectively. Under certain assumptions, we show that the filtering-out process can naturally provide a large suppression consistent with the observed dark matter density for a wide range of dark matter masses up to the Planck scale. Since the first-order phase transition is the decisive ingredient in our mechanism, a new connection is made between heavy dark matter scenarios and gravitational wave observations.

    hep-phPRD(2020)·99 citations
29. 29*

    Theory and applications of parton pseudodistributions

    A. V. Radyushkin🇺🇸

    We review the basic theory of the parton pseudodistributions approach and its applications to lattice extractions of parton distribution functions. The crucial idea of the approach is the realization that the correlator $M(z,p)$ of the parton fields is a function $\mathcal{M}(\nu ,-z^2)$ of Lorentz invariants $\nu =-(zp)$, the Ioffe time, and the invariant interval $z^2$. This observation allows to extract the Ioffe-time distribution $\mathcal{M}(\nu ,-z^2)$ from Euclidean separations $z$ accessible on the lattice. Another basic feature is the use of the ratio $\mathfrak{M}(\nu ,-z^2)\equiv \mathcal{M}(\nu ,-z^2)/\mathcal{M}(0,-z^2)$, that allows to eliminate artificial ultraviolet divergence generated by the gauge link for space-like intervals. The remaining $z^2$-dependence of the reduced Ioffe-time distribution $\mathfrak{M}(\nu ,-z^2)$ corresponds to perturbative evolution, and can be converted into the scale-dependence of parton distributions $f(x,{\mu }^2)$ using matching relations. The $\nu$-dependence of $\mathfrak{M}(\nu ,-z^2)$ governs the $x$-dependence of parton densities $f(x,{\mu }^2)$. The perturbative evolution was successfully observed in exploratory quenched lattice calculation. The analysis of its precise data provides a framework for extraction of parton densities using the pseudodistributions approach. It was used in the recently performed calculations of the nucleon and pion valence quark distributions. We also discuss matching conditions for the pion distribution amplitude and generalized parton distributions, the lattice studies of which are now in progress.

    hep-phhep-exhep-latInt.J.Mod.Phys.A(2020)·68 citations
30. 30*

    Searching for Earth/Solar Axion Halos

    Abhishek Banerjee🇮🇱 · Dmitry Budker🇩🇪 · Joshua Eby🇮🇱 · Victor V. Flambaum🇦🇺 · Hyungjin Kim🇮🇱 · Oleksii Matsedonskyi🇮🇱 · Gilad Perez🇮🇱

    We discuss the sensitivity of the present and near-future axion dark matter experiments to a halo of axions or axion-like particles gravitationally bound to the Earth or the Sun. The existence of such halos, assuming they are formed, renders a significant gain in the sensitivity of axion searches while satisfying all the present experimental bounds. The structure and coherence properties of these halos also imply novel signals, which can depend on the latitude or orientation of the detector. We demonstrate this by analysing the sensitivity of several distinct types of axion dark matter experiments.

    hep-phastro-ph.COphysics.atom-phJHEP(2020)·54 citations
31. 31*

    Physics potential of the ESS$\nu$SB

    M. Blennow🇪🇸 · E. Fernandez-Martinez🇪🇸 · T. Ota🇪🇸 · S. Rosauro-Alcaraz🇪🇸

    The ESS$\nu$SB project proposes to base a neutrino ''Super Beam'' of unprecedented luminosity at the European Spallation Source. The original proposal identified the second peak of the oscillation probability as the optimal to maximize the discovery potential to leptonic CP violation. However this choice reduces the statistics at the detector and penalizes other complementary searches such as the determination of the atmospheric oscillation parameters, particularly the octant of ${\theta }_{23}$ as well as the neutrino mass ordering. We explore how these shortcomings can be alleviated by the combination of the beam data with the atmospheric neutrino sample that would also be collected at the detector. We find that the combination not only improves very significantly these drawbacks, but also enhances both the CP violation discovery potential and the precision in the measurement of the CP violating phase, for which the facility was originally optimized, by lifting parametric degeneracies. We then reassess the optimization of the ESS$\nu$SB setup when the atmospheric neutrino sample is considered, with an emphasis in performing a measurement of the CP violating phase as precise as possible. We find that for the presently preferred value of $\delta \sim -\pi /2$, shorter baselines and longer running time in neutrino mode would be optimal. In these conditions, a measurement better than $14^{\circ }$ would be achievable for any value of the ${\theta }_{23}$ octant and the mass ordering. Conversely, if present and next generation facilities were not able to discover CP violation, longer baselines and more even splitting between neutrino and neutrino modes would be preferable. These choices would allow a $5\sigma$ discovery of CP violation for around a $60\%$ of the possible values of $\delta$ and to determine its value with a precision around $6^{\circ }$ if it is close to $0$ or $\pi$.

    hep-phhep-exEPJC(2020)·35 citations
32. 32*

    Systematically Localizable Operators for Quantum Simulations of Quantum Field Theories

    Natalie Klco🇺🇸 · Martin J. Savage🇺🇸

    Correlations and measures of entanglement in ground state wavefunctions of relativistic quantum field theories are spatially localized over length scales set by the mass of the lightest particle. We utilize this localization to design digital quantum circuits for preparing the ground states of lattice scalar quantum field theories. Controlled rotations that are exponentially localized in their position-space extent are found to provide exponentially convergent wavefunction fidelity. These angles scale with the correlation between sites and the classical two-point correlation function, as opposed to the more localized mutual information or the hyper-localized negativity. We anticipate that further investigations will uncover quantum circuit designs with controlled rotations dictated by the measures of entanglement. This work is expected to impact quantum simulations of systems of importance to nuclear physics, high-energy physics, and basic energy sciences research.

    ↳ quant-phhep-lathep-phhep-th+1PRA(2020)·46 citations
33. 33*

    Electric dipole moments of atoms and molecules produced by enhanced nuclear Schiff moments

    V.V. Flambaum🇦🇺 · V.A. Dzuba🇦🇺

    We perform calculations of the CP-violating atomic and molecular electric dipole moments (EDM) induced by the interaction of the nuclear Schiff moments with electrons. EDM of atoms Eu, Dy, Gd, Ac, Th, Pa, U, Np and Pu are of special interest since they have isotopes with strongly enhanced nuclear Schiff moments caused by the octupole nuclear deformation or soft octupole vibration mode. These atoms have open 4f or 5f shells making the calculations complicated. We use our special version of the configuration interaction method combined with the many-body perturbation theory method adopted for open f-shell case. To validate the method we perform similar calculations for simpler atoms (Xe, Hg, Tl+, Pb, Pb++, Rn, Ra) where some earlier results are available. In addition we present the estimates of the CP-violating nuclear spin - molecular axis interaction constants for molecules which may be of experimental interest including AcF, EuN, ThO, PbO and TlF. We also present updated values of the nuclear Schiff moments and atomic and molecular EDM expressed in terms of the CP-violating pi-meson - nucleon interaction constants g_0,g_1, g_2, QCD parameter theta and quark chromo-EDMs. The results may be used to test CP-violation theories and search for axion dark matter in atomic, molecular and solid state experiments.

    ↳ physics.atom-phhep-phnucl-thPRA(2020)·57 citations
34. 34*

    Background studies for the CODEX-b experiment: measurements and simulation

    Biplab Dey🇨🇳 · Jongho Lee🇨🇭 · Victor Coco🇨🇭 · Chang-Seong Moon🇰🇷

    This report presents results from a background measurement campaign for the CODEX-b proposal undertaken in August, 2018. The data were recorded in the DELPHI side of the LHCb cavern behind a 3.2~m concrete shield wall, during Run~2 proton-proton collisions with the goal of calibrating the simulation for the full CODEX-b detector. The maximum flux rate in the DELPHI side of the cavern was found to be around 0.6~mHz/cm${}^2$ across a vertical plane just behind the shield wall, parallel to the beam line. A detailed simulation under development within the LHCb {\tt Gauss} framework is described. This includes shielding elements pertinent for CODEX-b's acceptance -- the LHCb detector, the shield wall and cavern infrastructure. Additional flux from tracks not in the line of sight from the interaction point, but bent by the magnetic fields, are incorporated. Overall, the simulation overestimates the background flux compared to the measurement. Several cross-checks and avenues for further investigations are described.

    ↳ physics.ins-dethep-exhep-ph19 citations
35. 35*

    Does confinement imply CP invariance of the strong interactions?

    Y. Nakamura🇯🇵 · G. Schierholz🇩🇪

    The strong coupling constant $1/g^2$ and the vacuum angle $\theta$ of the SU(3) Yang-Mills theory are investigated in the infrared limit under the renormalization group flow. It is shown that the theory has an infrared attractive fixed point at $1/g^2=\theta =0$, which leads to linear confinement and naturally solves the strong CP problem. In particular, any initial value of $\theta \ne 0$ is found to be driven to $\theta =0$ at macroscopic distances, where quarks and gluons freeze into hadrons by the confinement mechanism.

    ↳ hep-lathep-phhep-thPoS(2019)·10 citations
36. 36*

    The model dependence of $m_{\varrho }/f_{\pi }$

    Daniel Nogradi🇭🇺 · Lorinc Szikszai🇭🇺

    Should a strongly coupled composite Higgs boson scenario be realized in Nature the most easily accessible experimental signal would be new particles made up of the same ingredients as the Higgs but with different quantum numbers. The lightest of these hypothetical new particles would probably be the vector mesons. In this contribution we report results on $m_{\varrho }/f_{\pi }$ in the chiral-continuum limit with $SU(3)$ gauge group and $N_f=2,3,4,5,6$ flavors of fundamental fermions. In addition we compare $m_{\varrho }/f_{\pi }$ results from various models with different gauge groups and fermion content. The main conclusion seems to be that the experimental measurement of this vector meson mass will be able to distinguish between gauge groups but less so between the fermion content.

    ↳ hep-lathep-phPoS(2019)·14 citations
37. 37*

    A response to Rubin & Heitlauf: "Is the expansion of the universe accelerating? All signs still point to yes"

    Jacques Colin🇫🇷 · Roya Mohayaee🇫🇷 · Mohamed Rameez🇩🇰 · Subir Sarkar🇬🇧

    We have shown (Colin et al., 2019) that the acceleration of the Hubble expansion rate inferred from Type Ia supernovae (SNe Ia) is, at $3.9\sigma$ significance, a dipole approximately aligned with the CMB dipole, while its monopole component, which can be interpreted as due to a Cosmological Constant or dark energy, is consistent with zero at $1.4\sigma$. This has been challenged by Rubin & Heitlauf (2019) who assert that the dipole arises because we made an incorrect assumption about the SNe Ia light-curve parameters (viz. took them to be sample- and redshift independent), and did not allow for the motion of the Solar system (w.r.t. the 'CMB frame' in which the CMB dipole supposedly vanishes). In fact what has an even larger impact on our finding is that we reversed the inconsistent "corrections" made for the peculiar velocities of the SNe Ia host galaxies w.r.t the CMB frame, which in fact serve to bias the lever arm of the Hubble diagram towards higher inferred values of the monopole. We demonstrate that even if all such corrections are made consistently and both sample- and redshift-dependence is allowed for in the standardisation of supernova light curves, the evidence for isotropic acceleration rises to just $2.8\sigma$. Thus the criticism of Rubin & Heitlauf serves only to highlight that "corrections" must be made to the SNe Ia data assuming the standard $\Lambda$CDM model, in order to recover it from the data.

    ↳ astro-ph.COgr-qchep-ph17 citations
38. 38*

    Inflation, Higher Spins and the Swampland

    Marco Scalisi🇧🇪

    We study the implications on inflation of an infinite tower of higher-spin states with masses falling exponentially at large field distances, as dictated by the Swampland Distance Conjecture. We show that the Higuchi lower bound on the mass of the tower automatically translates into an upper bound on the inflaton excursion. Strikingly, the mere existence of all spins in the tower forbids any scalar displacement whatsoever, at arbitrarily small Hubble scales, and it turns out therefore incompatible with inflation. A certain field excursion is allowed only if the tower has a cut-off in spin. Finally, we show that this issue is circumvented in the case of a tower of string excitations precisely because of the existence of such a cut-off, which decreases fast enough in field space.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2020)·27 citations
39. 39*

    A robust estimate of the Milky Way mass from rotation curve data

    Ekaterina V. Karukes🇵🇱 · Maria Benito🇧🇷 · Fabio Iocco🇧🇷 · Roberto Trotta🇬🇧 · Alex Geringer-Sameth🇬🇧

    We present a new estimate of the mass of the Milky Way, inferred via a Bayesian approach by making use of tracers of the circular velocity in the disk plane and stars in the stellar halo, as from the publicly available {\tt galkin} compilation. We use the rotation curve method to determine the dark matter distribution and total mass under different assumptions for the dark matter profile, while the total stellar mass is constrained by surface stellar density and microlensing measurements. We also include uncertainties on the baryonic morphology via Bayesian model averaging, thus converting a potential source of systematic error into a more manageable statistical uncertainty. We evaluate the robustness of our result against various possible systematics, including rotation curve data selection, uncertainty on the Sun's velocity $V_0$, dependence on the dark matter profile assumptions, and choice of priors. We find the Milky Way's dark matter virial mass to be ${\log }_{10}{M}_{200}^{\mathrm{DM}}/{\mathrm{M}}_{\odot }=11.92_{-0.05}^{+0.06}(\mathrm{stat})\pm 0.28\pm 0.27(\mathrm{syst})$ ($M_{200}^{\mathrm{DM}}=8.3_{-0.9}^{+1.2}(\mathrm{stat})\times 10^{11}{\mathrm{M}}_{\odot }$). We also apply our framework to Gaia DR2 rotation curve data and find good statistical agreement with the above results.

    ↳ astro-ph.GAhep-phJCAP(2020)·48 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.