Fri·May 10, 2019Friday·May 10, 2019

1. 01*

   Dark and Bright Signatures of Di-Higgs Production

   Alexandre Alves🇧🇷 · Tathagata Ghosh🇺🇸 · Farinaldo S. Queiroz🇧🇷

   If the Higgs boson decays to a pair of invisible particles, the number of di-Higgs events, where each Higgs decay into Standard Model (SM) particles, are reduced by a factor of two-third taking into account the current LHC bound on invisible decay width of the Higgs boson. We investigate the sensitivity of the upcoming high luminosity run of the LHC to di-Higgs production and subsequent decay to dark matter in the context of the singlet scalar extension of the SM augmented by a fermionic dark matter in the dark and bright channel $\gamma \gamma +/E_T$. Once systematic uncertainties on background yields are considered, this dark and bright channel presents competitive limits than $b\bar{b}+/E_T$ after a careful tuning of the kinematical cuts that raise the signal over background ratio. We further show that in a multivariate analysis, for an invisible branching fraction as low as $\sim 10$%, we obtain stronger bounds for the Higgs trilinear coupling from the $\gamma \gamma +/E_T$ channel compared to the $b\bar{b}\gamma \gamma$ final state. Finally, we demonstrate that the three channels $\gamma \gamma +/E_T$, $b\bar{b}+/E_T$ and $b\bar{b}\gamma \gamma$, complement each other in the search for di-Higgs production with non-SM trilinear couplings when an invisible decay mode is present.

   hep-phhep-exPRD(2019)·7 citations
2. 02*

   An N2HDM Solution for the possible 96 GeV Excess

   T. Biekötter🇪🇸 · M. Chakraborti🇪🇸 · S. Heinemeyer🇪🇸

   We discuss a ~3 sigma signal (local) in the light Higgs-boson search in the diphoton decay mode at ~96 GeV as reported by CMS, together with a ~2 sigma excess (local) in the bb final state at LEP in the same mass range. We review the interpretation of this possible signal as a Higgs boson in the 2~Higgs Doublet Model with an additional real Higgs singlet (N2HDM). It is shown that the lightest Higgs boson of the N2HDM can perfectly fit both excesses simultaneously, while the full Higgs-boson sector is in agreement with all Higgs-boson measurements and exclusion bounds as well as other theoretical and experimental constraints. It is demonstrated that in particular the N2HDM type~II and can fit the data best, leading to a supersymmetric interpretation. The NMSSM and the munuSSM are briefly reviewed in this respect.

   hep-phPoS(2019)·21 citations
3. 03*

   Probing double parton scattering via associated open charm and bottom production in ultraperipheral $pA$ collisions

   Edgar Huayra🇧🇷 · Emmanuel G. de Oliveira🇧🇷 · Roman Pasechnik🇸🇪

   In this article, we propose a novel channel for phenomenological studies of the double-parton scattering (DPS) based upon associated production of charm $c\bar{c}$ and bottom $b\bar{b}$ quark pairs in well-separated rapidity intervals in ultra-peripheral high-energy proton-nucleus collisions. This process provides a direct access to the double-gluon distribution in the proton at small-$x$ and enables one to test the factorised DPS pocket formula. We have made the corresponding theoretical predictions for the DPS contribution to this process at typical LHC energies and beyond and we compute the energy-independent (but photon momentum fraction dependent) effective cross section.

   hep-phEPJC(2019)·11 citations
4. 04*

   Chiral symmetry breaking, entanglement, and the nucleon spin decomposition

   Silas R. Beane🇺🇸 · Peter Ehlers🇺🇸

   The nucleon is naturally viewed as a bipartite system of valence spin -- defined by its non-vanishing chiral charge -- and non-valence or sea spin. The sea spin can be traced over to give a reduced density matrix, and it is shown that the resulting entanglement entropy acts as an order parameter of chiral symmetry breaking in the nucleon. In the large-$N_c$ limit, the entanglement entropy vanishes and the valence spin accounts for all of the nucleon spin, while in the limit of maximal entanglement entropy, the nucleon loses memory of the valence spin and consequently has spin dominated by the sea. The nucleon state vector in the chiral basis, fit to low-energy data, gives a valence spin content consistent with experiment and lattice QCD determinations, and has large entanglement entropy.

   hep-phhep-latnucl-thMod.Phys.Lett.A(2019)·34 citations
5. 05*

   Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model

   Nikolas Kauer🇬🇧 · Alexander Lind🇬🇧 · Philipp Maierhöfer🇩🇪 · Weimin Song🇬🇧

   A detailed study of Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model (1HSM) is presented for the WW and tt decay modes with fully leptonic WW decay. We explore interference effects for benchmark points with a heavy Higgs mass that significantly exceeds 2*m_t. In the WW channel, the Higgs signal and the interfering continuum background are loop induced. In the tt channel, which features a tree-level background, we also calculate the interference with the one-loop background, which, due to the appearance of the absorptive part, is found to dominate the normalisation and shape of differential Higgs distributions and should therefore be considered in experimental analyses. The commonly used geometric average K-factor approximation K_interference ~ (K_Higgs*K_background)^(1/2) is not appropriate. We calculate with massive top and bottom quarks. Our 1HSM and SM implementation in Sherpa+OpenLoops is publicly available and can be used as parton-level integrator or event generator.

   hep-phhep-exJHEP(2019)·11 citations
6. 06*

   Maximizing the Impact of New Physics in $b\to c\tau \nu$ Anomalies

   Pouya Asadi🇺🇸 · David Shih🇺🇸

   We develop a rigorous, semi-analytical method for maximizing any $b\to c\tau \nu$ observable in the full 20-real-dimensional parameter space of the dimension 6 effective Hamiltonian, given some fixed values of $R_{D^{(\ast )}}$. We apply our method to find the maximum allowed values of $F_{D^{\ast }}^L$ and $R_{J/\psi }$, two observables which have both come out higher than their SM predictions in recent measurements by the Belle and LHCb collaborations. While the measurements still have large error bars, they add to the existing $R_{D^{(\ast )}}$ anomaly, and it is worthwhile to consider NP explanations. It has been shown that none of the existing, minimal models in the literature can explain the observed values of $F_{D^{\ast }}^L$ and $R_{J/\psi }$. Using our method, we will generalize beyond the minimal models and show that there is no combination of dimension 6 Wilson operators that can come within $1\sigma$ of the observed $R_{J/\psi }$ value. By contrast, we will show that the observed value of $F_{D^{\ast }}^L$ can be achieved, but only with sizable contributions from tensor and mixed-chirality vector Wilson coefficients.

   hep-phhep-exPRD(2019)·32 citations
7. 07*

   Same-sign WW Scattering in the HEFT: Discoverability vs. EFT Validity

   P. Kozow🇵🇱 · L. Merlo🇪🇸 · S. Pokorski🇵🇱 · M. Szleper🇵🇱

   Vector boson scatterings are fundamental processes to shed light on the nature of the electroweak symmetry breaking mechanism. Deviations from the Standard Model predictions on the corresponding observables can be interpreted in terms of effective field theories, that however undergo consistency conditions. In this paper, the same-sign W W scattering is considered within the HEFT context and the correct usage of the effective field theory approach is discussed. Regions of the parameters space are identified where a signal of new physics could be measured at HL-LHC with a significance of more than 5$\sigma$ and the effective field theory description is consistently adopted. These results are then translated into bounds on the $\xi$ parameter in the composite Higgs scenario. The discussion on the agreement with previous literature and the comparison with the equivalent analysis in the SMEFT case are also included.

   hep-phhep-exJHEP(2019)·29 citations
8. 08*

   $R_{D^{\ast }}$ or $R_{D\pi }$: closing the theoretical gap?

   J. E. Chavez-Saab🇲🇽 · Marxil Sánchez🇲🇽 · Genaro Toledo🇲🇽

   Measurements of the $R_{D^{\ast }}$ parameter remain in tension with the standard model prediction, despite recent results helping to close the gap. In this work, we revisit the standard model considerations for the prediction. We pay particular attention to the theoretical prediction considering the full 4-body decay $(B\to l\nu D^{\ast }\to l\nu D\pi )$, which introduces the longitudinal degree of freedom of the $D^{\ast }$. We show that this does not introduce sizeable effects at the current precision. This modifies our previous finding (Phys. Rev. D 98 056014 (2018)) where a numerical bug led us to a different conclusion. Thus, the results on $R_{D\pi }$ are consistent with $R_{D^{\ast }}$, and the difference between the several values can be traced back to the form factor used and the restrictions incorporated to determine their parameters. There is still tension between the experimental world average and the most accurate theoretical estimate, leaving the possibility of presence of new physics scenarios open.

   hep-ph0 citations
9. 09*

   Annihilation signatures of neutron dark decay models in neutron oscillation and proton decay searches

   Wai-Yee Keung🇺🇸 · Danny Marfatia🇺🇸 · Po-Yan Tseng🇯🇵

   We point out that two models that reconcile the neutron lifetime anomaly via dark decays of the neutron, also predict dark matter-neutron ($\bar{\chi }-n$) annihilation that may be observable in neutron-antineutron oscillation and proton decay searches at Super-Kamiokande, Hyper-Kamiokande and DUNE. We study signatures of $\bar{\chi }n\to \gamma {\pi }^0$ (or multi-${\pi }^0$) and $\bar{\chi }n\to \varphi \gamma {\pi }^0$ (or $\varphi +$multi-${\pi }^0$), where $\varphi$ is an almost massless boson in one of the two models.

   hep-phhep-exJHEP(2019)·15 citations
10. 10*

    A still unsettled issue in the nucleon spin decomposition problem : On the role of surface terms and gluon topology

    Masashi Wakamatsu🇯🇵

    In almost all the past analyses of the decomposition of the nucleon spin into its constituents, surface terms are simply assumed to vanish and not to affect the integrated sum rule of the nucleon spin. However, several authors claim that neglect of surface terms is not necessarily justified, especially owing to possible nontrivial topological configuration of the gluon field in the QCD vacuum. There also exist some arguments indicating that the nontrivial gluon topology would bring about a delta-function type singularity at zero Bjorken variable into the longitudinally polarized gluon distribution function, thereby invalidating a naive partonic sum rule for the total nucleon spin. In the present paper, we carefully examine the role of surface terms in the nucleon spin decomposition problem. We shall argue that surface terms do not prevent us from obtaining a physically meaningful decomposition of the nucleon spin. In particular, we demonstrate that nontrivial topology of the gluon field would not bring about a delta-function type singularity into the longitudinally polarized gluon distribution functions. We also make some critical comments on the recent analyses of the role of surface terms in the density level decomposition of the total nucleon angular momentum as well as that of the total photon angular momentum.

    hep-phnucl-thEPJA(2019)·7 citations
11. 11*

    Pileup and Underlying Event Mitigation with Iterative Constituent Subtraction

    Peter Berta🇩🇪 · Lucia Masetti🇩🇪 · David W. Miller🇺🇸 · Martin Spousta🇨🇿

    The hard-scatter processes in hadronic collisions are often largely contaminated with soft background coming from pileup in proton-proton collisions, or underlying event in heavy-ion collisions. This paper presents a new background subtraction method for jets and event observables (such as missing transverse energy) which is based on the previously published Constituent Subtraction algorithm. The new subtraction method, called Iterative Constituent Subtraction, applies event-wide implementation of Constituent Subtraction iteratively in order to fully equilibrate the background subtraction across the entire event. Besides documenting the new method, we provide guidelines for setting the free parameters of the subtraction algorithm. Using particle-level simulation, we provide a comparison of Iterative Constituent Subtraction with several existing methods from which we conclude that the new method has a significant potential to improve the background mitigation in both proton-proton and heavy-ion collisions.

    hep-phhep-exJHEP(2019)·54 citations
12. 12*

    Constraints on Flavor-Diagonal Non-Standard Neutrino Interactions from Borexino Phase-II

    S. K. Agarwalla · M. Agostini · K. Altenmüller · S. Appel · V. Atroshchenko · Z. Bagdasarian · D. Basilico · G. Bellini · J. Benziger · D. Bick · G. Bonfini · D. Bravo and 94 other authors

    The Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar-${\nu }_e$ survival probability $P_{ee}(E)$, and the chiral couplings of the neutrino and electron. Some theories of physics beyond the Standard Model postulate the existence of Non-Standard Interactions (NSI's) which modify the chiral couplings and $P_{ee}(E)$. In this paper, we search for such NSI's, in particular, flavor-diagonal neutral current interactions that modify the ${\nu }_{e}e$ and ${\nu }_{\tau }e$ couplings using Borexino Phase II data. Standard Solar Model predictions of the solar neutrino fluxes for both high- and low-metallicity assumptions are considered. No indication of new physics is found at the level of sensitivity of the detector and constraints on the parameters of the NSI's are placed. In addition, with the same dataset the value of ${\sin }^2{\theta }_W$ is obtained with a precision comparable to that achieved in reactor antineutrino experiments.

    hep-phastro-ph.SRhep-exphysics.ins-detJHEP(2020)·58 citations
13. 13*

    Resolving $R_D$ and $R_{D^{\ast }}$ anomalies

    Suman Kumbhakar🇮🇳 · Ashutosh Kumar Alok🇮🇳 · Dinesh Kumar🇮🇳 · S Uma Sankar🇮🇳

    The current world averages of the ratios $R_{D^{(\ast )}}$ are about $4\sigma$ away from their Standard Model prediction. These measurements indicate towards the violation of lepton flavor universality in $b\to cl\bar{\nu }$ decay. The different new physics operators, which can explain the $R_{D^{(\ast )}}$ measurements, have been identified previously. We show that a simultaneous measurement of the polarization fractions of $\tau$ and $D^{\ast }$ and the angular asymmetries $A_{FB}$ and $A_{LT}$ in $B\to D^{\ast }\tau \bar{\nu }$ decay can distinguish all the new physics amplitudes and hence uniquely identify the Lorentz structure of new physics.

    hep-phhep-exSpringer Proc.Phys.(2019)·1 citation
14. 14*

    Neutrino Mass Ordering at DUNE: an Extra $\nu$-Bonus

    Christoph A. Ternes🇪🇸 · Stefano Gariazzo🇪🇸 · Rasmi Hajjar🇪🇸 · Olga Mena🇪🇸 · Michel Sorel🇪🇸 · Mariam Tórtola🇪🇸

    We study the possibility of extracting the neutrino mass ordering at the future Deep Underground Neutrino Experiment using atmospheric neutrinos, which will be available before the muon neutrino beam starts being perational. The large statistics of the atmospheric muon neutrino and antineutrino samples at the far detector, together with the baselines of thousands of kilometers that these atmospheric (anti)neutrinos travel, provide the ideal ingredients to extract the neutrino mass ordering via matter effects in the neutrino propagation through the Earth. Crucially, muon capture by Argon provides excellent charge-tagging, allowing to disentangle the neutrino and antineutrino signature. This is a critical extra benefit of having a Liquid Argon Time Projection Chamber as far detector, that could render a $4\sigma$ extraction of the mass ordering after ten years of exposure.

    hep-phhep-exPRD(2019)·28 citations
15. 15*

    A Global Analysis of the Standard Model Effective Field Theory in the Production and Decay Channels of a Single Top Quark

    Rhea Moutafis🇫🇷

    A global analysis of the Standard Model Effective Field Theory (SMEFT) with SFitter is performed using measurements of single top quark production and top quark decay processes from ATLAS and CMS at center-of-mass energies of 7, 8 and 13 TeV. NLO QCD corrections are included in the theoretical predictions of all involved processes. Correlations among theoretical and experimental uncertainties are accounted for using DataPrep, which has been developed by the author. Using the dataset prepared by this software, constraints for the relevant degrees of freedom are derived. Almost all constraints are more than three times more stringent than the values of the literature. This thesis sets the technical and conceptual framework for a global fit of the entire top quark and Higgs boson sectors, which the author is involved in. The project marks an important milestone towards a truly global analysis constraining physics beyond the Standard Model in a model-independent way.

    hep-ph1 citation
16. 16*

    Probing new types of $P_c$ states inspired by the interaction between an $S$-wave charmed baryon and an anticharmed meson in a $\bar{T}$ doublet state

    Fu-Lai Wang🇨🇳 · Rui Chen🇨🇳 · Zhan-Wei Liu🇨🇳 · Xiang Liu🇨🇳

    Inspired by the observations of three $P_c$ states, we systematically investigate interactions between an $S$-wave charmed baryon ${\mathcal{B}}_c^{(\ast )}={\Lambda }_c/{\Sigma }_c/{\Sigma }_c^{\ast }$ and an anticharmed meson $\bar{T}={\bar{D}}_1/{\bar{D}}_2^{\ast }$ with the one-pion-exchange potential model and the one-boson-exchange potential model, and search for possible new types of $P_c$ states with the structures of ${\mathcal{B}}_c^{(\ast )}\bar{T}$. Both $S$-$D$ wave mixing and coupled channel effects are considered. Our results suggest that in some ${\mathcal{B}}_c^{(\ast )}\bar{T}$ systems there are ideal candidates of new types of $P_c$ states, i.e., the ${\Sigma }_c{\bar{D}}_1$ state with $I(J^P)=1/2(1/2^{+})$, the ${\Sigma }_c{\bar{D}}_2^{\ast }$ state with $I(J^P)=1/2(3/2^{+})$, the ${\Sigma }_c^{\ast }{\bar{D}}_1$ state with $I(J^P)=1/2(1/2^{+})$, and the ${\Sigma }_c^{\ast }{\bar{D}}_2^{\ast }$ states with $I(J^P)=1/2(1/2^{+},3/2^{+})$, and we suggest that these predicted new types of $P_c$ states can be detected in the process ${\Lambda }_b^0\to \psi (2S)p{\pi }^{-}$. Meanwhile, we also extend our study to the interactions between an $S$-wave charmed baryon and a charmed meson in a $T$ doublet, and we predict a series of double-charm molecular pentaquarks.

    hep-phPRC(2020)·53 citations
17. 17*

    Stability of three neutrino flavor conversion in supernovae

    Christian Döring🇩🇪 · Rasmus S. L. Hansen🇩🇪 · Manfred Lindner🇩🇪

    Neutrino-neutrino interactions can lead to collective flavor conversion in the dense parts of a core collapse supernova. Growing instabilities that lead to collective conversions have been studied intensely in the limit of two-neutrino species and occur for inverted mass ordering in the case of a perfectly spherical supernova. We examine two simple models of colliding and intersecting neutrino beams and show, that for three neutrino species instabilities exist also for normal mass ordering even in the case of a fully symmetric system. Whereas the instability for inverted mass ordering is associated with $\Delta m_{31}^2$, the new instability we find for normal mass ordering is associated with $\Delta m_{21}^2$. As a consequence, the growth rate of these new instabilities for normal ordering is smaller by about an order of magnitude compared to the rates of the well studied case of inverted ordering.

    hep-phastro-ph.HEastro-ph.SRJCAP(2019)·17 citations
18. 18*

    On systematic and GR effects on muon $g-2$ experiments

    Alessio Notari🇪🇸 · Daniele Bertacca🇮🇹

    We derive in full generality the equations that govern the time dependence of the energy $\mathcal{E}$ of the decay electrons in a muon $g-2$ experiment. We include both electromagnetic and gravitational effects and we estimate possible systematics on the measurements of $g-2\equiv 2(1+a)$, whose experimental uncertainty will soon reach $\Delta a/a\approx 10^{-7}$. In addition to the standard modulation of $\mathcal{E}$ when the motion is orthogonal to a constant magnetic field $B$, with angular frequency ${\omega }_a=ea|B|/m$, we study effects due to: (1) a non constant muon $\gamma$ factor, in presence of electric fields $E$, (2) a correction due to a component of the muon velocity along $B$ (the `pitch correction'), (3) corrections to the precession rate due to $E$ fields, (4) non-trivial spacetime metrics. Oscillations along the radial and vertical directions of the muon lead to oscillations in $\mathcal{E}$ with a relative size of order $10^{-6}$, for the BNL $g-2$ experiment. We then find a subleading effect in the `pitch' correction, leading to a frequency shift of $\Delta {\omega }_a/{\omega }_a\approx \mathcal{O}(10^{-9})$ and subleading effects of about $\Delta {\omega }_a/{\omega }_a\approx \mathrm{few}\times \mathcal{O}(10^{-8}-10^{-9})$ due to $E$ fields. Finally we show that GR effects are dominated by the Coriolis force, due to the Earth rotation with angular frequency ${\omega }_T$, leading to a correction of about $\Delta {\omega }_a/{\omega }_a\approx {\omega }_T/(\gamma {\omega }_a)\approx \mathcal{O}(10^{-12})$. A similar correction might be more appreciable for future electron $g-2$ experiments, being of order $\Delta {\omega }_a/{\omega }_{a,\mathrm{el}}\approx {\omega }_T/({\omega }_{a,\mathrm{el}})\approx 7\times 10^{-13}$, compared to the present experimental uncertainty, $\Delta a_{\mathrm{el}}/a_{\mathrm{el}}\approx 10^{-10}$, and forecasted to reach soon $\Delta a_{\mathrm{el}}/a_{\mathrm{el}}\approx 10^{-11}$.

    hep-phgr-qchep-exJHEP(2019)·1 citation
19. 19*

    Some Phenomenological Aspects of Kaon Photoproduction in the Extreme Kinematics

    S. Sakinah🇮🇩 · S. Clymton🇮🇩 · T. Mart🇮🇩

    We have investigated phenomenological aspects of kaon photoproduction in three different extreme kinematics. The first kinematics of interest is the threshold region. At the threshold we have investigated the convergence of kaon photoproduction amplitude by expanding the square of the amplitude in terms of the ratio $m_K/m$, where $m_K$ is the mass of kaon and $m$ is the averaged mass of nucleon and $\Lambda$-hyperon. The amplitude is calculated from the appropriate Feynman diagrams by using the pseudovector theory. The contact diagram as a consequence of the PCAC hypothesis is also taken into account in the amplitude. Our finding indicates that the convergence can be only achieved if the amplitude was expanded up to at least $12^{\mathrm{th}}$ order. As a consequence, applications of some theoretical calculations based on the expansion the scattering amplitude, such as the Low Energy Theorem or Soft Kaon Approximation, cannot be easily managed in kaon photoproduction. The second kinematics is the forward region, where we could assume only $t$-channel contributes to the process. Here we have investigated the effect of amplitude expansion on the extraction of the coupling constants $g_{K^{+}\Lambda p}$ and $g_{K_1^{+}\Lambda p}^V$. The last kinematics is the backward region, where we have also assumed that only $u$-channel survives and we could extract the leading coupling constants $g_{K^{+}\Lambda p}$ and $g_{K^{+}{\Sigma }^{0}p}$.

    hep-phActa Phys.Polon.B(2019)·3 citations
20. 20*

    Three loop QCD corrections to heavy quark form factors

    J. Ablinger🇦🇹 · J. Blümlein🇩🇪 · P. Marquard🇩🇪 · N. Rana🇩🇪 · C. Schneider🇦🇹

    Higher order calculations in perturbative Quantum Field Theories often produce coupled linear systems of differential equations which factorize to first order. Here we present an algorithm to solve such systems in terms of iterated integrals over an alphabet the structure of which is implied by the coefficient matrix of the given system. We apply this method to calculate the master integrals in the color-planar and complete light quark contributions to the three-loop massive form factors.

    hep-phhep-thmath-phmath.MPJ.Phys.Conf.Ser.(2020)·2 citations
21. 21*

    Analytic form of the full two-loop five-gluon all-plus helicity amplitude

    S. Badger🇬🇧 · D. Chicherin🇩🇪 · T. Gehrmann🇨🇭 · G. Heinrich🇩🇪 · J. M. Henn🇩🇪 · T. Peraro🇨🇭 · P. Wasser🇩🇪 · Y. Zhang🇩🇪 · S. Zoia🇩🇪

    We compute the full-color two-loop five-gluon amplitude for the all-plus helicity configuration. In order to achieve this, we calculate the required master integrals for all permutations of the external legs, in the physical scattering region. We verify the expected divergence structure of the amplitude, and extract the finite hard function. We further validate our result by checking the factorization properties in the collinear limit. Our result is fully analytic and valid in the physical scattering region. We express it in a compact form containing logarithms, dilogarithms and rational functions.

    hep-phhep-thPRL(2019)·133 citations
22. 22*

    Probing neutrino transition magnetic moments with coherent elastic neutrino-nucleus scattering

    O.G. Miranda🇲🇽 · D.K. Papoulias🇪🇸 · M. Tórtola🇪🇸 · J. W. F. Valle🇪🇸

    We explore the potential of current and next generation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) experiments in probing neutrino electromagnetic interactions. On the basis of a thorough statistical analysis, we determine the sensitivities on each component of the Majorana neutrino transition magnetic moment (TMM), $\left|{\Lambda }_i\right|$, that follow from low-energy neutrino-nucleus experiments. We derive the sensitivity to neutrino TMM from the first CE$\nu$NS measurement by the COHERENT experiment, at the Spallation Neutron Source. We also present results for the next phases of COHERENT using HPGe, LAr and NaI[Tl] detectors and for reactor neutrino experiments such as CONUS, CONNIE, MINER, TEXONO and RED100. The role of the CP violating phases in each case is also briefly discussed. We conclude that future CE$\nu$NS experiments with low-threshold capabilities can improve current TMM limits obtained from Borexino data.

    hep-phJHEP(2019)·94 citations
23. 23*

    Diffractive dijet production in impact parameter dependent saturation models

    Farid Salazar🇺🇸 · Bjoern Schenke🇺🇸

    We study coherent diffractive dijet production in electron-hadron and electron-nucleus collisions within the dipole picture. We provide semi-analytic results for the differential cross section and elliptic anisotropy in the angle between dijet transverse momentum and hadron recoil momentum. We demonstrate the direct relation between angular moments of the dipole amplitude in coordinate space and angular moments of the diffractive dijet cross sections. To perform explicit calculations we employ two different saturation models, extended to include the target geometry. In the limit of large photon virtuality or quark masses, we find fully analytic results that allow direct insight into how the differential cross section and elliptic anisotropy depend on the saturation scale, target geometry, and kinematic variables. We further provide numerical results for more general kinematics in collisions at a future electron-ion collider, and study the effects of approaching the saturated regime on diffractive dijet observables.

    hep-phnucl-thPRD(2019)·68 citations
24. 24*

    Higgs Boson Studies at Future Particle Colliders

    J. de Blas (1 and 2)🇮🇹 · M. Cepeda (3)🇪🇸 · J. D'Hondt (4)🇧🇪 · R. K. Ellis (5)🇬🇧 · C. Grojean (6 and 7)🇩🇪 · B. Heinemann (6 and 8)🇩🇪 · F. Maltoni (9 and 10)🇧🇪 · A. Nisati (11)🇮🇹 · E. Petit (12)🇫🇷 · R. Rattazzi (13)🇨🇭 · W. Verkerke (14) ((1) Dipartimento di Fisica e Astronomia Galileo Galilei, Universita di Padova, Italy, (2) Istituto Nazionale di Fisica Nucleare (INFN), Italy, (3) Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Spain, (4) Inter-University Institute for High Energies (IIHE), Vrije Universiteit Brussel, Belgium, (5) IPPP, University of Durham, UK, (6) Deutsches Elektronen-Synchrotron (DESY), Germany, (7) Institut für Physik, Humboldt-Universität, Germany, (8) Albert-Ludwigs-Universität Freiburg, Germany, (9) Centre for Cosmology, Particle Physics and Phenomenology, Université catholique de Louvain, Belgium, (10) Dipartimento di Fisica e Astronomia, Università di Bologna and INFN, Sezione di Bologna, Italy, (11) Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Roma, Italy, (12) Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France, (13) Theoretical Particle Physics Laboratory (LPTP), EPFL, Switzerland, (14) Nikhef and University of Amsterdam, the Netherlands)🇳🇱

    This document aims to provide an assessment of the potential of future colliding beam facilities to perform Higgs boson studies. The analysis builds on the submissions made by the proponents of future colliders to the European Strategy Update process, and takes as its point of departure the results expected at the completion of the HL-LHC program. This report presents quantitative results on many aspects of Higgs physics for future collider projects of sufficient maturity using uniform methodologies.

    hep-phhep-exJHEP(2020)·501 citations
25. 25*

    The Return of the WIMP: Missing Energy Signals and the Galactic Center Excess

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

    In a recent work, we emphasized that an excess in tri-lepton events plus missing energy observed by the ATLAS experiment at the LHC could be interpreted as a signal of low energy supersymmetry. In such a scenario the lightest neutralino mass is approximately $m_{\chi }\simeq 60$ GeV and the direct Dark Matter detection cross section is naturally below the current bound. In this work we present simple extensions of this scenario that lead to an explanation of the gamma ray excess at the center of the galaxy observed by Fermi-LAT, as well as the anti-proton excess observed by AMS-02. These extensions include the addition of a small CP violating phase in the neutralino sector or the addition of a light CP-odd Higgs scalar. Our study is of special relevance in view of a recent analysis that casts doubt on the previously accepted preference for mili-second pulsars as the origin of the galactic center excess.

    hep-phastro-ph.HEhep-exPRD(2019)·28 citations
26. 26*

    Resummed prediction for Higgs boson production through $b\bar{b}$ annihilation at N${}^3$LL

    Ajjath A H🇮🇳 · Amlan Chakraborty🇮🇳 · Goutam Das🇩🇪 · Pooja Mukherjee🇮🇳 · V. Ravindran🇮🇳

    We present an accurate theoretical prediction for the production of Higgs boson through bottom quark annihilation at the LHC up to next-to-next-to-next-to leading order (N${}^3$LO) plus next-to-next-to-next-to-leading logarithmic (N${}^3$LL) accuracy. We determine the third order perturbative Quantum Chromodynamics (QCD) correction to the process dependent constant in the resummed expression using the three loop bottom quark form factor and third order quark soft distribution function. Thanks to the recent computation of N${}^3$LO corrections to this production cross-section from all the partonic channels, an accurate matching can be obtained for a consistent predictions at N${}^3$LO+N${}^3$LL accuracy in QCD. We have studied in detail the impact of resummed threshold contributions to inclusive cross-sections at various centre-of-mass energies and also discussed their sensitivity to renormalization and factorization scales at next-to-next-to leading order (NNLO) matched with next-to-next-to leading logarithm (NNLL). At N${}^3$LO+N${}^3$LL, we predict the cross-section for different centre-of-mass energies using the recently available results in \cite{Duhr:2019kwi} as well as study the renormalization scale dependence at the same order.

    hep-phJHEP(2019)·55 citations
27. 27*

    Anatomy of the $tthh$ Physics at HL-LHC

    Lingfeng Li🇨🇳 · Ying-Ying Li🇨🇳 · Tao Liu🇨🇳

    The $tthh$ production at colliders contain rich information on the nature of Higgs boson. In this article, we systematically studied its physics at High-Luminosity Large Hadron Collider (HL-LHC), using exclusive channels with multiple ($\ge 5$) $b$-jets and one lepton ($5b1\ell$), multiple ($\ge 5$) $b$-jets and opposite-sign di-lepton ($5b2\ell$), same-sign di-lepton (SS2$\ell$), multiple leptons (multi-$\ell$), and di-tau resonance ($\tau \tau$). The scenarios analyzed include: (1) the $tthh$ production in Standard Model; (2) the $tthh$ production mediated by anomalous cubic Higgs self-coupling and $tthh$ contact interaction; (3) heavy Higgs ($H$) production with $ttH\to tthh$; and (4) pair production of fermionic top partners ($T$) with $TT\to tthh$. To address the complication of event topologies and the mess of combinatorial backgrounds, a tool of Boosted-Decision-Tree was applied in the analyses. The $5b1\ell$ and SS2$\ell$ analyses define the two most promising channels, resulting in slightly different sensitivities. For non-resonant $tthh$ production, a combination of these exclusive analyses allows for its measurment in the SM with a statistical significance $\sim 0.9\sigma$ (with $S/B>1\%$), and may assist partially breaking the sensitivity degeneracy w.r.t. the cubic Higgs self-coupling, a difficulty usually thought to exist in gluon fusion di-Higgs analysis at HL-LHC. These sensitivities were also projected to future hadron colliders at 27 TeV and 100 TeV. For resonant $tthh$ productions, the heavy Higgs boson in type II Two-Higgs-Doublet-Model could be efficiently searched for between the mass thresholds $2m_h<m_H<2m_t$ and even beyond that, for relatively small $\tan \beta$, while the fermionic top partners in composite Higgs models could be probed for up to $\sim 1.5$ TeV and $\sim 1.7$ TeV, for Br$(T\to th)=25\%$ and $50\%$, respectively.

    hep-phhep-exPRD(2020)·7 citations
28. 28*

    Thermo-magnetic corrections to $\pi$-$\pi$ Scattering Lengths in the Linear Sigma Model

    Marcelo Loewe🇨🇱 · Enrique Muñoz🇨🇱 · Renato Zamora🇨🇱

    In this article, we extend our previous study of the $\pi$-$\pi$ scattering lengths under the presence of an external magnetic field, including finite temperature effects. The novelty of this work is precisely the introduction of temperature into the discussion, and its interplay with the magnetic field. As in the previous article, we base our analysis in the linear sigma-model, and our calculations are exact within this context. Although the effects are comparatively small, it is interesting to remark that magnetic field and temperature display opposite effects over the scattering lengths.

    hep-phhep-thPRD(2019)·6 citations
29. 29*

    Strange quark suppression from a simultaneous Monte Carlo analysis of parton distributions and fragmentation functions

    N. Sato🇺🇸 · C. Andres🇺🇸 · J. J. Ethier🇳🇱 · W. Melnitchouk🇺🇸

    We perform the first simultaneous extraction of unpolarized parton distributions and fragmentation functions from a Monte Carlo analysis of inclusive and semi-inclusive deep-inelastic scattering, Drell-Yan lepton-pair production, and single-inclusive $e^{+}{e}^{-}$ annihilation data. We use data resampling techniques to thoroughly explore the Bayesian posterior distribution of the extracted functions, and use $k$-means clustering on the parameter samples to identify the configurations that give the best description across all reactions. Inclusion of the semi-inclusive data reveals a strong suppression of the strange quark distribution at parton momentum fractions $x\gtrsim 0.01$, in contrast with the ATLAS observation of enhanced strangeness in $W^{\pm }$ and $Z$ production at the LHC. Our study reveals significant correlations between the strange quark density and the strange $\to$ kaon fragmentation function needed to simultaneously describe semi-inclusive $K^{\pm }$ production data from COMPASS and inclusive $K^{\pm }$ spectra in $e^{+}{e}^{-}$ annihilation from ALEPH and SLD, as well as between the strange and light antiquark densities in the proton.

    hep-phhep-exnucl-thPRD(2020)·118 citations
30. 30*

    Combined explanations of $(g-2{)}_{\mu }$, $(g-2{)}_e$ and implications for a large muon EDM

    Andreas Crivellin🇨🇭 · Martin Hoferichter🇺🇸

    We consider possible beyond-the-Standard-Model (BSM) effects that can accommodate both the long-standing tension in the anomalous magnetic moment of the muon, $a_{\mu }=(g-2{)}_{\mu }/2$, as well as the emerging $2.5\sigma$ deviation in its electron counterpart, $a_e=(g-2{)}_e/2$. After performing an EFT analysis, we consider BSM physics realized above the electroweak scale and find that a simultaneous explanation becomes possible in models with chiral enhancement. However, this requires a decoupling of the muon and electron BSM sectors to avoid the strong constraints from $\mu \to e\gamma$. In particular, this decoupling implies that there is no reason to expect the muon electric dipole moment (EDM) $d_{\mu }$ to be correlated with the electron EDM $d_e$, avoiding the very stringent limits for the latter. While some of the parameter space for $d_{\mu }$ favored by $a_{\mu }$ could be tested at the $(g-2{)}_{\mu }$ experiments at Fermilab and J-PARC, a dedicated muon EDM experiment at PSI would be able to probe most of this region.

    hep-phhep-exPoS(2020)·29 citations
31. 31*

    Precise predictions for multi-$\mathrm{TeV}$ and $\mathrm{PeV}$ energy neutrino scattering rates

    Rhorry Gauld🇳🇱

    The scattering rate of multi-$\mathrm{TeV}$ and $\mathrm{PeV}$ energy neutrinos is fast becoming an interesting topic in (astro)particle-physics. This is due to experimental progress at Neutrino Telescopes such as IceCube which have begun to gain sensitivity to the flux of neutrinos in this energy range. In view of this, a precise calculation of the scattering rate of neutrinos upon atoms is presented. The two main components of the calculation are the differential cross-section predictions for neutrino scattering upon an atomic nucleus (such as that which make up water), as well as upon atomic electrons. In the first case, the predictions for neutrino-nucleon cross-sections in charged- and neutral-current scattering are refined by including resonant contributions generated within the photon field of the nucleus, which alter the considered distributions by up to $\approx 4\%$. In the latter case, radiative corrections are provided for all $2\to 2$ scattering processes of the form ${\bar{\nu }}_e{e}^{-}\to f{\bar{f}}^{\prime }$. For antineutrino energies of $E_{{\bar{\nu }}_e}\approx 6\mathrm{PeV}$, where these processes become resonantly enhanced (the Glashow resonance) and dominate the total cross-section, these corrections amount to $\approx -10\%$.

    hep-phastro-ph.HEPRD(2019)·37 citations
32. 32*

    Novel implementation of the multipole expansion to quarkonium hadronic transitions

    Antonio Pineda🇪🇸 · Jaume Tarrús Castellà🇪🇸

    We compute hadronic transitions between heavy quarkonium states with two, or one, pion/eta particles in the final state. We use the multipole expansion but not the twist expansion. The latter cannot be justified for the energy release of hadronic transitions between heavy quarkonium states with different principal quantum numbers. Instead, we use a counting based on the dimension of the interpolating field of the hybrid. This alternative counting allows us to still use chiral low-energy theorems to compute the pion production by local gluonic operators. We explore the phenomenological impact of this counting. Remarkably enough, for the two-pion transitions, we obtain the same predictions for the normalized differential decay rate as those obtained assuming the twist expansion. We implement this computational scheme using the hadronic representation of the effective theory potential NRQCD. We assume that the inverse Bohr radius of the heavy quarkonium is much larger than ${\Lambda }_{\mathrm{QCD}}$ but do not impose any constraint on the relative size of ${\Lambda }_{\mathrm{QCD}}$ and the typical kinetic energy of the bound state.

    hep-phhep-exnucl-thPRD(2019)·24 citations
33. 33*

    New constraints on Lorentz invariance violation with polarized gamma-ray bursts

    Jun-Jie Wei🇨🇳

    Lorentz invariance violations (LIV) can yield vacuum birefringence, which results in an energy-dependent rotation of the polarization vector of linearly polarized emission from astrophysical sources. It is believed that if the relative rotation angle ($\Delta \Theta$) of the polarization vector of high energy photons with respect to that of low energy photons is larger than $\pi /2$, then the net polarization of the signal would be significantly depleted and could not be as high as the observed level. Hence, the measurement of high polarization implies that $\Delta \Theta$ should not be too large. In this work, we assemble recent detections of prompt emission polarization in gamma-ray bursts (GRBs), all of whom have high detection significance. Following the method shown in Lin et al. (2016), we give a detailed calculation on the polarization evolution arising from the LIV effect for each GRB, and confirm that, even if $\Delta \Theta$ is approaching to $\pi /2$, the net polarization is not severely suppressed, and more than 60\% of the initial polarization can be conserved. Applying this method to our GRB polarimetric data, we improve existing sensitivities to LIV involving photons by factors ranging from two to ten. In addition, we prove that our constraints are not greatly affected by uncertainties in the spectral parameters of GRBs.

    ↳ astro-ph.HEgr-qchep-phMNRAS(2019)·22 citations
34. 34*

    Angular distribution of gamma-ray emission from velocity-dependent dark matter annihilation in subhalos

    Kimberly K. Boddy🇺🇸 · Jason Kumar🇺🇸 · Jack Runburg🇺🇸 · Louis E. Strigari🇺🇸

    We consider the effect of velocity-dependent dark matter annihilation on the angular distribution of gamma rays produced in dark matter subhalos. We assume that the dark matter potential is spherically symmetric, characterized by a scale radius and scale density, and the velocity distribution is isotropic. We find that the effect of velocity-dependent dark matter annihilation is largely determined by dimensional analysis; the angular size of gamma-ray emission from an individual subhalo is rescaled by a factor which depends on the form of the dark matter distribution, but not on the halo parameters, while the relative normalization of the gamma-ray flux from different mass subhalos is rescaled by a factor which depends on the halo parameters, but not on the form of the dark matter distribution. We apply our results to a Navarro-Frenk-White profile for the case of an individual subhalo and comment on the application of these results to a distribution of subhalos.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2019)·27 citations
35. 35*

    Axion core - halo mass and the black hole - halo mass relation: constraints on a few parsec scales

    Vincent Desjacques🇮🇱 · Adi Nusser🇮🇱

    If the dark matter is made of ultra-light axions, stable solitonic cores form at the centers of virialized halos. In some range for the mass $m$ of the axion particle, these cores are sufficiently compact and can mimic supermassive black holes (SMBH) residing at galactic nuclei. We use the solitonic core--halo mass relation, validated in numerical simulations, to constrain a new range of allowed axion mass from measurements of the SMBH mass in (pseudo)bulge and bulgeless galaxies. These limits are based on observations of galactic nuclei on scales smaller than 10 pc. Our analysis suggests that $m<10^{-18}$ eV is ruled out by the data. We briefly discuss whether an attractive self-interaction among axions could alleviate this constraint.

    ↳ astro-ph.COgr-qchep-phMNRAS(2019)·37 citations
36. 36*

    Charmonium resonances with $J^{PC}=1^{--}$ and $3^{--}$ from $\bar{D}D$ scattering on the lattice

    S. Piemonte🇩🇪 · S. Collins🇩🇪 · D. Mohler🇩🇪 · M. Padmanath🇩🇪 · S. Prelovsek🇸🇮

    We present a lattice QCD study of charmonium resonances and bound states with $J^{PC}=1^{--}$ and $3^{--}$ near the open-charm threshold, taking into account their strong transitions to $\bar{D}D$. Vector charmonia are the most abundant in the experimentally established charmonium spectrum, while recently LHCb reported also the first discovery of a charmonium with likely spin three. The $\bar{D}D$ scattering amplitudes for partial waves $l=1$ and $l=3$ are extracted on the lattice by means of the Lüscher formalism, using multiple volumes and inertial frames. Parameterizations of the scattering amplitudes provide masses and widths of the resonances, as well as the masses of bound states. CLS ensembles with 2+1 dynamical flavors of non-perturbatively $O(a)$ improved Wilson quarks are employed with $m_{\pi }\simeq 280$ MeV, a single lattice spacing of $a\simeq 0.086$ fm and two lattice spatial extents of $L=24$ and $32$. Two values of the charm quark mass are considered to examine the influence of the position of the $\bar{D}D$ threshold on the hadron masses. For the lighter charm quark mass we find the vector resonance $\psi (3770)$ with mass $m=3780(7)$ MeV and coupling $g=16.0{(}_{-0.2}^{+2.1})$ (related to the width), both consistent with their experimental values. The vector $\psi (2S)$ appears as a bound state with $m=3666(10)$ MeV. The charmonium resonance with $J^{PC}=3^{--}$ is found at $m=3831{(}_{-16}^{+10})$ MeV, consistent with the $X(3842)$ recently discovered by LHCb. At our heavier charm-quark mass the $\psi (2S)$ as well as the $\psi (3770)$ are bound states and the $X(3842)$ remains a resonance. We stress that all quoted uncertainties are only statistical, while lattice spacing effects and the approach to the physical point still need to be explored. This study of conventional charmonia sets the stage for more challenging future studies of unconventional charmonium-like states.

    ↳ hep-lathep-phPRD(2019)·43 citations
37. 37*

    Axion RG flows and the holographic dynamics of instanton densities

    Yuta Hamada🇬🇷 · Elias Kiritsis🇬🇷 · Francesco Nitti🇫🇷 · Lukas T. Witkowski🇫🇷

    Axionic holographic RG flow solutions are studied in the context of general Einstein-Axion-Dilaton theories. A non-trivial axion profile is dual to the (non-perturbative) running of the $\theta$-term for the corresponding instanton density operator. It is shown that a non-trivial axion solution is incompatible with a non-trivial (holographic) IR conformal fixed point. Imposing a suitable axion regularity condition allows to select the IR geometry in a unique way. The solutions are found analytically in the asymptotic UV and IR regimes, and it is shown that in those regimes the axion backreaction is always negligible. The axion backreaction may become important in the intermediate region of the bulk. To make contact with the axion probe limit solutions, a systematic expansion of the solution is developed. Several concrete examples are worked out numerically. It is shown that the regularity condition always implies a finite allowed range for the axion source parameter in the UV. This translates into the existence of a finite (but large) number of saddle-points in the large $N_c$ limit. This ties in well with axion-swampland conjectures.

    ↳ hep-thhep-phJ.Phys.A(2019)·15 citations
38. 38*

    $\alpha$-attractor dark energy in view of next-generation cosmological surveys

    Carlos García-García🇪🇸 · Pilar Ruíz-Lapuente🇪🇸 · David Alonso🇬🇧 · M. Zumalacárregui🇺🇸

    The $\alpha$-attractor inflationary models are nowadays favored by CMB Planck observations. Their similarity with canonical quintessence models motivates the exploration of a common framework that explains both inflation and dark energy. We study the expected constraints that next-generation cosmological experiments will be able to impose for the dark energy $\alpha$-attractor model. We systematically account for the constraining power of SNIa from WFIRST, BAO from DESI and WFIRST, galaxy clustering and shear from LSST and Stage-4 CMB experiments. We assume a tensor-to-scalar ratio, $10^{-3}<r<10^{-2}$, which permits to explore the wide regime sufficiently close, but distinct, to a cosmological constant, without need of fine tunning the initial value of the field. We find that the combination S4CMB + LSST + SNIa will achieve the best results, improving the FoM by almost an order of magnitude; respect to the S4CMB + BAO + SNIa case. We find this is also true for the FoM of the $w_0-w_a$ parameters. Therefore, future surveys will be uniquely able to probe models connecting early and late cosmic acceleration.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·12 citations
39. 39*

    Prospects of Cosmic Superstring Detection through Microlensing of Extragalactic Point-Like Sources

    David F. Chernoff🇺🇸 · Ariel Goobar🇸🇪 · Janina J. Renk🇸🇪

    The existence of cosmic superstrings may be probed by astronomical time domain surveys. When crossing the line of sight to point-like sources, strings produce a distinctive microlensing signature. We consider two avenues to hunt for a relic population of superstring loops: frequent monitoring of (1) stars in Andromeda, lensed by loops in the haloes of the Milky-Way and Andromeda and (2) supernovae at cosmological distances, lensed by loops in the intergalactic medium. We assess the potential of such experiments to detect and/or constrain strings with a range of tensions, $10^{-15}\lesssim G\mu /c^2\lesssim 10^{-6}$. The practical sensitivity is tied to cadence of observations which we explore in detail. We forecast that high-cadence monitoring of $\sim 10^5$ stars on the far side of Andromeda over a year-long period will detect microlensing events if $G\mu /c^2\sim 10^{-13}$, while $\sim 10^6$ stars will detect events if $10^{-13.5}<G\mu /c^2<10^{-11.5}$; the upper and lower bounds of the accessible tension range continue to expand as the number of stars rises. We also analyse the ability to reject models in the absence of fluctuations. While challenging, these studies are within reach of forthcoming time-domain surveys. Supernova observations can hypothetically constrain models with $10^{-12}<G\mu /c^2<10^{-6}$ without any optimisation of the survey cadence. However, the event rate forecast suggests it will be difficult to reject models of interest. As a demonstration, we use observations from the Pantheon Type Ia supernova cosmology data-set to place modest constraints on the number density of cosmic superstrings in a poorly tested region of the parameter space.

    ↳ astro-ph.COgr-qchep-phMNRAS(2020)·4 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.