Mon·Jun 15, 2020Monday·June 15, 2020

1. 01*

   On next to soft corrections to Drell-Yan and Higgs Boson productions

   A.H. Ajjath · Pooja Mukherjee🇮🇳 · V. Ravindran🇮🇳

   We present a framework that resums threshold enhanced large logarithms to all orders in perturbation theory for the production of a pair of leptons in Drell-Yan process and of Higgs boson in gluon fusion as well as in bottom quark annihilation. We restrict ourselves to contributions from diagonal partonic channels. These logarithms include the distributions $((1-z{)}^{-1}{\ln }^i(1-z){)}_{+}$ resulting from soft plus virtual (SV) and the logarithms ${\ln }^i(1-z)$ from next-to-SV (NSV) contributions. We use collinear factorisation and renormalisation group invariance to achieve this. The former allows one to define a Soft-Collinear (SC) function which encapsulates soft and collinear dynamics of the perturbative results to all orders in strong coupling constant. The logarithmic structure of these results are governed by universal infrared anomalous dimensions and process dependent functions of Sudakov differential equation that the SC satisfies. The solution to the differential equation is obtained by proposing an all-order ansatz in dimensional regularisation, owing to several state-of-the-art perturbative results available to third order. The $z$ space solutions thus obtained provide an integral representation to sum up large logarithms originating from both soft and collinear configurations, conveniently in Mellin $N$ space. We show that in $N$ space, tower of logarithms $a_s^n/N^{\alpha }{\ln }^{2n-\alpha }(N),a_s^n/N^{\alpha }{\ln }^{2n-1-\alpha }(N)\cdots$ etc for $\alpha =0,1$ are summed to all orders in $a_s$.

   hep-phPRD(2022)·54 citations
2. 02*

   Eikonal amplitudes and non-global logarithms from the BMS equation

   Hana Benslama🇩🇿 · Yazid Delenda🇩🇿 · Kamel Khelifa-Kerfa🇸🇦 · Abdelaziz Mohamed Ibrahim🇩🇿

   The Banfi-Marchesini-Smye (BMS) equation accounts for non-global logarithms to all orders in perturbation theory in the large-Nc approximation. We show that the squared amplitudes for the emission of soft energy-ordered gluons are correctly embedded in this equation, and explicitly verify that they coincide with those derived in our previous work in the large-Nc limit up to sixth order in the strong coupling. We perform analytical calculations for the non-global logarithms up to fourth order for the specific hemisphere mass distribution in e+ e- collisions, thus confirming our previous semi-numerical results. We show that the solution to the BMS equation may be cast into a product of an infinite number of exponentials each of which resums a class of Feynman diagrams that manifest a symmetry pattern, and explicitly carry out the computation of the first of these exponentials.

   hep-phPhys.Part.Nucl.Lett.(2021)·5 citations
3. 03*

   Baryon and lepton number intricacies in axion models

   Jérémie Quevillon🇫🇷 · Christopher Smith🇫🇷

   Because the Peccei-Quinn (PQ) symmetry has to be anomalous to solve the strong CP puzzle, some colored and chiral fermions have to transform non-trivially under this symmetry. But when the SM fermions are charged, as in the PQ or DFSZ models, this symmetry ends up entangled with the SM global symmetries, baryon (B) and lepton (L) numbers. This raises several questions addressed in this paper. First, the compatibility of axion models with some explicit B and/or L violating effects is analyzed, including those arising from seesaw mechanisms, electroweak instanton interactions, or explicit B and L violating effective operators. Second, how many of these effects can be simultaneously present is quantified, along with the consequences for the axion mass and vacuum alignment if too many of them are introduced. Finally, large classes of B and/or L violating interactions without impact on axion phenomenology are identified, like for example the various implementations of the type I and II seesaw mechanisms in the DFSZ context.

   hep-phPRD(2020)·16 citations
4. 04*

   QCD2019 Workshop Summary

   S.J. Brodsky🇺🇸 · V.D. Burkert🇺🇸 · D.S. Carman🇺🇸 · J.P. Chen🇺🇸 · Z.-F. Cui🇨🇳 · M. Döring🇺🇸 · H.G. Dosch🇩🇪 · J.P. Draayer🇺🇸 · L. Elouadrhiri🇺🇸 · D.I. Glazier🇬🇧 · A.N. Hiller Blin🇺🇸 · T. Horn🇺🇸 and 17 other authors

   The topical workshop {\it Strong QCD from Hadron Structure Experiments} took place at Jefferson Lab from Nov. 6-9, 2019. Impressive progress in relating hadron structure observables to the strong QCD mechanisms has been achieved from the {\it ab initio} QCD description of hadron structure in a diverse array of methods in order to expose emergent phenomena via quasi-particle formation. The wealth of experimental data and the advances in hadron structure theory make it possible to gain insight into strong interaction dynamics in the regime of large quark-gluon coupling (the strong QCD regime), which will address the most challenging problems of the Standard Model on the nature of the dominant part of hadron mass, quark-gluon confinement, and the emergence of the ground and excited state hadrons, as well as atomic nuclei, from QCD. This workshop aimed to develop plans and to facilitate the future synergistic efforts between experimentalists, phenomenologists, and theorists working on studies of hadron spectroscopy and structure with the goal to connect the properties of hadrons and atomic nuclei available from data to the strong QCD dynamics underlying their emergence from QCD. These results pave the way for a future breakthrough extension in the studies of QCD with an Electron-Ion Collider in the U.S.

   hep-phhep-latnucl-exnucl-thIJMPE(2020)·76 citations
5. 05*

   Probing dark photons with plasma haloscopes

   Graciela B. Gelmini🇺🇸 · Alexander J. Millar🇸🇪 · Volodymyr Takhistov🇺🇸 · Edoardo Vitagliano🇺🇸

   Dark photons (DPs) produced in the early Universe are well-motivated dark matter (DM) candidates. We show that the recently proposed tunable plasma haloscopes are particularly advantageous for DP searches. While in-medium effects suppress the DP signal in conventional searches, plasma haloscopes make use of metamaterials that enable resonant absorption of the DP by matching its mass to a tunable plasma frequency and thus enable efficient plasmon production. Using thermal field theory, we confirm the in-medium DP absorption rate within the detector. This scheme allows to competitively explore a significant part of the DP DM parameter space in the DP mass range of $6-400$ $\mu$eV. If a signal is observed, the observation of a daily or annual modulation of the signal would be crucial to clearly identify the signal as due to DP DM and could shed light on the production mechanism.

   hep-phastro-ph.COhep-exPRD(2020)·56 citations
6. 06*

   Kinetic Mixing, Dark Photons and Extra Dimensions III: Brane Localized Dark Matter

   Thomas G. Rizzo🇺🇸 · George N. Wojcik🇺🇸

   Extra dimensions have proven to be a very useful tool in constructing new physics models. In earlier work, we began investigating toy models for the 5-D analog of the kinetic mixing/vector portal scenario where the interactions of dark matter, taken to be, e.g., a complex scalar, with the brane-localized fields of the Standard Model (SM) are mediated by a massive $U(1{)}_D$ dark photon living in the bulk. These models were shown to have many novel features differentiating them from their 4-D analogs and which, in several cases, avoided some well-known 4-D model building constraints. However, these gains were obtained at the cost of the introduction of a fair amount of model complexity, e.g., dark matter Kaluza-Klein excitations. In the present paper, we consider an alternative setup wherein the dark matter and the dark Higgs, responsible for $U(1{)}_D$ breaking, are both localized to the 'dark' brane at the opposite end of the 5-D interval from where the SM fields are located with only the dark photon now being a 5-D field. The phenomenology of such a setup is explored for both flat and warped extra dimensions and compared to the previous more complex models.

   hep-phJHEP(2021)·15 citations
7. 07*

   Collapsing domain walls in the two-Higgs-doublet model and deep insights from the EDM

   Ning Chen🇨🇳 · Tong Li🇨🇳 · Zhaolong Teng🇨🇳 · Yongcheng Wu🇨🇦

   We study the domain wall solutions in the general two-Higgs-doublet model (2HDM) with a CP-violating phase. The 2HDM with the spontaneouse CP violation is found to have domain wall solutions whose tensions are $\mathcal{O}(10^6){\mathrm{GeV}}^3$, which are excluded by the Zel'dovich-Kobzarev-Okun bound. With the explicit CP-violating (CPV) terms as the so-called biased term in the scalar potential, domain walls can collapse in the early Universe. The sizes of the explicit CP violation can be constrained from the Big Bang nucleosynthesis. This constraint is converted to the CPV mixing of ${\alpha }_c$, and is mostly sensitive to the mass splittings between two heavy neutral Higgs bosons. We estimate the possible gravitational wave signals and the electric dipole moment (EDM) predictions due to the domain wall collapsing. It turns out that the peak spectrum of the GW from the domain wall collapsing cannot be probed in any future program. In contrast, the untenable regions with very tiny explicit CPV parameter in the Higgs potential has been partially excluded by the latest electron EDM measurements at the ACME-II and will be further confirmed or excluded by the future ACME-III projection.

   hep-phgr-qcphysics.atom-phJHEP(2020)·32 citations
8. 08*

   Constraining gluon density of pions at large $x$ by pion-induced $J/\psi$ production

   Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

   The gluon distributions of the pion obtained from various global fits exhibit large variations among them. Within the framework of the color evaporation model, we show that the existing pion-induced $J/\psi$ production data, usually not included in the global fits, can impose useful additional constraints on the pion parton distribution functions (PDFs). In particular, these data can probe the pion's gluon densities at large $x$. Existing pion-induced $J/\psi$ data covering a broad range of beam momenta are compared with next-to-leading-order QCD calculations using various sets of pion PDFs. It is found that $J/\psi$ data measured at forward rapidity and at sufficiently high beam momentum are sensitive to the large-$x$ gluon distribution of pions. The current $J/\psi$ data favor the Sutton-Martin-Roberts-Stirling and Gluck-Reya-Vogt pion PDFs, containing significant gluon content at large $x$.

   hep-phhep-exnucl-exnucl-thPRD(2020)·39 citations
9. 09*

   Heavy-flavor PDF evolution and variable-flavor number scheme uncertainties in deep-inelastic scattering

   S. Alekhin🇩🇪 · J. Bluemlein🇩🇪 · S. Moch🇩🇪

   We consider a detailed account on the construction of the heavy-quark parton distribution functions for charm and bottom, starting from $n_f=3$ light flavors in the fixed-flavor number (FFN) scheme and by using the standard decoupling relations for heavy quarks in QCD. We also account for two-mass effects. Furthermore, different implementations of the variable-flavor-number (VFN) scheme in deep-inelastic scattering (DIS) are studied, with the particular focus on the resummation of large logarithms in $Q^2/m_h^2$, the ratio the virtuality of the exchanged gauge-boson $Q^2$ to the heavy-quark mass squared $m_h^2$. A little impact of resummation effects if found in the kinematic range of the existing data on the DIS charm-quark production so that they can be described very well within the FFN scheme. Finally, we study the theoretical uncertainties associated to the VFN scheme, which manifest predominantly at small $Q^2$.

   hep-phPRD(2020)·17 citations
10. 10*

    Andreev reflection at Hadron/Color superconductor interface

    Yuki Juzaki🇯🇵 · Motoi Tachibana🇯🇵

    We consider the phenomenon of the Andreev reflection of "hadrons" at the interface between hadronic and color superconducting phases, which are expected to appear in the neutron star interior. Here, hadrons are defined as a superposition of constituent quarks, each of which is Andreev-reflected. We study what kind of reflections are possible to come out of incident mesons and baryons in the hadronic phase, attached to different color superconducting phases. Then, some peculiar patterns of the reflections are obtained.

    hep-phcond-mat.supr-conhep-thActa Phys.Polon.B(2020)·3 citations
11. 11*

    Heavy baryon wave functions, Bakamjian-Thomas approach to form factors, and observables in ${\Lambda }_b\to {\Lambda }_c\left({\frac{1}{2}}^{\pm }\right)\ell \overline{\nu }$ transitions

    D. Bečirević🇫🇷 · A. Le Yaouanc🇫🇷 · V. Morénas🇫🇷 · L. Oliver🇫🇷

    Motivated by the calculation of observables in the decays ${\Lambda }_b\to {\Lambda }_c\left({\frac{1}{2}}^{\pm }\right)\ell \overline{\nu }$, as tests of Lepton Flavor Universality, we present a calculation of form factors in the quark model. Our scheme combines a spectroscopic model, providing the internal wave functions, and the Bakamjian-Thomas relativistic formalism to deduce the wave functions in motion and current matrix elements, that amount in the heavy quark limit to the Isgur-Wise (IW) function. For baryons we meet difficulties using standard spectroscopic models, leading us to propose a simple phenomenological model : a Q-pointlike-diquark model, non-relativistic with harmonic oscillator forces, with a reasonable low-lying spectrum and good slope of the IW function. We extract this slope from Lattice data and find ${\rho }_{\Lambda }^2\sim 2$. We are not able to reproduce the right ${\rho }_{\Lambda }^2$ when using standard linear + Coulomb potential models, both with three quarks $Qqq$ or in a Q-pointlike-diquark picture. These difficulties seem to derive from the high sensitivity of ${\rho }_{\Lambda }^2$ to the structure of the light quark subsystem. After fixing the parameters of our interim model to yield correct spectrum and ${\rho }_{\Lambda }^2$, we compute observables. Bjorken sum rule shows that the inelastic IW function is large, and therefore ${\Lambda }_b\to {\Lambda }_c\left({\frac{1}{2}}^{-},{\frac{3}{2}}^{-}\right)\ell \overline{\nu }$ could be studied at LHCb. Some observables in the $\tau$ case present zeroes for specific values of $q^2$ that could be tests of the Standard Model.

    hep-phPRD(2020)·18 citations
12. 12*

    New sensitivity of current LHC measurements to vector-like quarks

    A. Buckley🇬🇧 · J. M. Butterworth🇬🇧 · L. Corpe🇬🇧 · D. Huang🇬🇧 · P. Sun🇬🇧

    Quark partners with non-chiral couplings appear in several extensions of the Standard Model. They may have non-trivial generational structure to their couplings, and may be produced either in pairs via the strong and EM interactions, or singly via the new couplings of the model. Their decays often produce heavy quarks and gauge bosons, which will contribute to a variety of already-measured "Standard Model" cross-sections at the LHC. We present a study of the sensitivity of such published LHC measurements to vector-like quarks, first comparing to limits already obtained from dedicated searches, and then broadening to some so-far unstudied parameter regions.

    hep-phhep-exSciPost Phys.(2020)·59 citations
13. 13*

    Model-independent constraints with extended dark matter EFT

    Tommi Alanne🇩🇪 · Giorgio Arcadi🇮🇹 · Florian Goertz🇩🇪 · Valentin Tenorth🇩🇪 · Stefan Vogl🇩🇪

    We systematically explore the phenomenology of the recently proposed extended dark matter effective field theory (\eDMEFT), which allows for a consistent effective description of DM scenarios across different energy scales. The framework remains applicable at collider energies and is capable of reproducing the correct relic abundance by including a dynamical mediator particle to the dark sector, while maintaining correlations dictated by gauge invariance in a `model-independent' way. Taking into account present and future constraints from direct- and indirect-detection experiments, from collider searches for missing energy and for scalar resonances in vector-boson, di-jet, and Higgs-pair final states, as well as from the relic abundance as measured by Planck, we determine viable regions in the parameter space, both for scalar and pseudoscalar mediator. In particular, we point out regions where cancellations in the direct-detection cross section appear leading to allowed islands for scalar mediators that could be missed in a naive simplified-model approach, but are present in the full $D=5$ effective theory, as well as a general opening of the parameter space due to consistently considering all operators at a given mass dimension. Thus, canonical WIMP-like scenarios can survive even the next generation of direct-detection experiments in different mass regimes, while potentially becoming testable at the high-luminosity LHC.

    hep-phJHEP(2020)·18 citations
14. 14*

    Challenges in Semileptonic B Decays

    P. Gambino🇮🇹 · A.S. Kronfeld🇺🇸 · M. Rotondo🇮🇹 · C. Schwanda🇦🇹 · F. Bernlochner🇩🇪 · A. Bharucha🇫🇷 · C. Bozzi🇮🇹 · M. Calvi🇮🇹 · L. Cao🇩🇪 · G. Ciezarek🇨🇭 · C.T.H. Davies🇬🇧 · A.X. El-Khadra🇺🇸 and 13 other authors

    Two of the elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix, $|V_{ub}|$ and $|V_{cb}|$, are extracted from semileptonic B decays. The results of the B factories, analysed in the light of the most recent theoretical calculations, remain puzzling, because for both $|V_{ub}|$ and $|V_{cb}|$ the exclusive and inclusive determinations are in clear tension. Further, measurements in the $\tau$ channels at Belle, Babar, and LHCb show discrepancies with the Standard Model predictions, pointing to a possible violation of lepton flavor universality. LHCb and Belle II have the potential to resolve these issues in the next few years. This article summarizes the discussions and results obtained at the MITP workshop held on April 9--13, 2018, in Mainz, Germany, with the goal to develop a medium-term strategy of analyses and calculations aimed at solving the puzzles. Lattice and continuum theorists working together with experimentalists have discussed how to reshape the semileptonic analyses in view of the much higher luminosity expected at Belle II, searching for ways to systematically validate the theoretical predictions in both exclusive and inclusive B decays, and to exploit the rich possibilities at LHCb.

    hep-phhep-exhep-latEPJC(2020)·109 citations
15. 15*

    Gravitational wave signals of dark matter freeze-out

    Danny Marfatia🇺🇸 · Po-Yan Tseng🇰🇷

    We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

    hep-phastro-ph.COhep-exJHEP(2021)·43 citations
16. 16*

    Acoplanarity of QED pairs accompanied by nuclear dissociation in ultra-peripheral heavy ion collisions

    James Daniel Brandenburg🇨🇳 · Wei Li🇺🇸 · Lijuan Ruan🇺🇸 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸 · Shuai Yang🇺🇸 · Wangmei Zha🇨🇳

    This paper investigates the transverse momentum broadening effect for electromagnetic production of dileptons in ultra-peripheral heavy ion collisions accompanied by nuclear dissociation. The electromagnetic dissociation probability of nuclei for different neutron multiplicities is estimated, which could serve as a centrality definition (i.e. impact parameter estimate) in ultra-peripheral collisions. In the framework of lowest-order QED, the acoplanarity of dilepton pairs is calculated for different neutron emission scenarios in ultra-peripheral collisions, indicating significant impact-parameter dependence. The verification of impact-parameter dependence is crucially important to understand the broadening effect observed in hadronic heavy-ion collisions.

    hep-phnucl-th23 citations
17. 17*

    Power expansion for heavy quarkonium production at next-to-leading order in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ annihilation

    Kyle Lee🇺🇸 · George Sterman🇺🇸

    We study heavy quarkonium production associated with gluons in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ annihilation as an illustration of the perturbative QCD (pQCD) factorization approach, which incorporates the first nonleading power in the energy of the produced heavy quark pair. We show how the renormalization of the four-quark operators that define the heavy quark pair fragmentation functions using dimensional regularization induces "evanescent" operators that are absent in four dimensions. We derive closed forms for short-distance coefficients for quark pair production to next-to-leading order (${\alpha }_s^2$) in the relevant color singlet and octet channels. Using non-relativistic QCD (NRQCD) to calculate the heavy quark pair fragmentation functions up to $v^4$ in the velocity expansion, we derive analytical results for the differential energy fraction distribution of the heavy quarkonium. Calculations for ${}^3{S}_1^{[1]}$ and ${}^1{S}_0^{[8]}$ channels agree with analogous NRQCD analytical results available in the literature, while several color-octet calculations of energy fraction distributions are new. We show that the remaining corrections due to the heavy quark mass fall off rapidly in the energy of the produced state. To explore the importance of evolution at energies much larger than the mass of the heavy quark, we solve the renormalization group equation perturbatively to two-loop order for the ${}^3{S}_1^{[1]}$ case.

    hep-phnucl-thJHEP(2020)·5 citations
18. 18*

    Can $\overline{\mathrm{MS}}$ parton distributions be negative?

    Alessandro Candido🇮🇹 · Stefano Forte🇮🇹 · Felix Hekhorn🇮🇹

    It is common lore that Parton Distribution Functions (PDFs) in the $\overline{\mathrm{MS}}$ factorization scheme can become negative beyond leading order due to the collinear subtraction which is needed in order to define partonic cross sections. We show that this is in fact not the case and next-to-leading order (NLO) $\overline{\mathrm{MS}}$ PDFs are actually positive in the perturbative regime. In order to prove this, we modify the subtraction prescription, and perform the collinear subtraction in such a way that partonic cross sections remain positive. This defines a factorization scheme in which PDFs are positive. We then show that positivity of the PDFs is preserved when transforming from this scheme to $\overline{\mathrm{MS}}$, provided only the strong coupling is in the perturbative regime, such that the NLO scheme change is smaller than the LO term.

    hep-phJHEP(2020)·71 citations
19. 19*

    Maximal axion misalignment from a minimal model

    Junwu Huang🇨🇦 · Amalia Madden🇨🇦 · Davide Racco🇨🇦 · Mario Reig🇪🇸

    The QCD axion is one of the best motivated dark matter candidates. The misalignment mechanism is well known to produce an abundance of the QCD axion consistent with dark matter for an axion decay constant of order $10^{12}$ GeV. For a smaller decay constant, the QCD axion, with Peccei-Quinn symmetry broken during inflation, makes up only a fraction of dark matter unless the axion field starts oscillating very close to the top of its potential, in a scenario called "large-misalignment". In this scenario, QCD axion dark matter with a small axion decay constant is partially comprised of very dense structures. We present a simple dynamical model realising the large-misalignment mechanism. During inflation, the axion classically rolls down its potential approaching its minimum. After inflation, the Universe reheats to a high temperature and a modulus (real scalar field) changes the sign of its minimum dynamically, which changes the sign of the mass of a vector-like fermion charged under QCD. As a result, the minimum of the axion potential during inflation becomes the maximum of the potential after the Universe has cooled through the QCD phase transition and the axion starts oscillating. In this model, we can produce QCD axion dark matter with a decay constant as low as $6\times 10^9\mathrm{GeV}$ and an axion mass up to 1 meV. We also summarise the phenomenological implications of this mechanism for dark matter experiments and colliders.

    hep-phJHEP(2020)·36 citations
20. 20*

    An Extended Analysis of Heavy Neutral Leptons during Big Bang Nucleosynthesis

    Nashwan Sabti🇬🇧 · Andrii Magalich🇳🇱 · Anastasiia Filimonova🇩🇪

    Heavy Neutral Leptons (HNLs) are strongly motivated by theory due to their capability of simultaneously explaining the observed phenomena of dark matter, neutrino oscillations and the baryon asymmetry of the Universe. The existence of such particles would affect the expansion history of the Universe and the synthesis of primordial abundances of light elements. In this work we review, revise and extend the phenomenology of HNLs during the Big Bang Nucleosynthesis (BBN) epoch for masses up to 1 GeV. This is of great importance, as BBN is able to provide complementary bounds to those from upcoming and proposed laboratory experiments. To this end we have developed a high-precision Boltzmann code that simulates BBN in the presence of HNLs and takes into account all relevant HNL decay channels, as well as subsequent interactions of decay products (thermalization and decay showers), dilution due to QCD phase transition, active neutrino oscillations and corrections to the weak reaction rates. We present robust bounds on the lifetime and mixing angles of HNLs for masses $3\mathrm{MeV}\le m_N\le 1\mathrm{GeV}$ and show that BBN is able to constrain HNL lifetimes down to $0.03-0.05$ s, depending on the mixing pattern. Moreover, combining our results with current experimental searches, we can exclude HNLs that mix purely with electron neutrinos up to $\sim$450 MeV and those that mix purely with muon neutrinos up to $\sim$360 MeV, in both cases for lifetimes up to at least a few tens of seconds. Finally, we compare the BBN constraints with those obtained from Cosmic Microwave Background observations and explore how our results will be improved by a number of upcoming and proposed laboratory experiments.

    hep-phastro-ph.COJCAP(2020)·141 citations
21. 21*

    Searching for the Higgsino-Bino Sector at the LHC

    Jia Liu🇺🇸 · Navin McGinnis🇺🇸 · Carlos E.M. Wagner🇺🇸 · Xiao-Ping Wang🇺🇸

    We study the search for electroweakinos at the 13 TeV LHC in the case of heavy scalar superpartners. We consider both the direct production mode and the one associated with the decay of heavy Higgs bosons, and concentrate on the case of light Higgsinos and Binos. In this case, the direct production searches becomes more challenging than in the light Wino scenario. In the direct production mode, we use the current experimental searches to set the reach for these particles at larger luminosities, and we emphasize the relevance of considering both the neutral gauge boson and the neutral Higgs decay modes of the second and third lightest neutralino. We show the complementarity of these searches with the ones induced by the decay of the heavy Higgs bosons, which are dominated by the associated production of the lightest neutralino with the second and third lightest ones, with the latter decaying into gauge bosons. We show that, depending on the value of $\tan \beta$, the Higgs boson decay channel remains competitive with the direct production channel up to heavy Higgs boson masses of about 1 TeV. Moreover, this search is not limited by the same kinematic considerations as the ones in the direct production mode and can cover masses up to the kinematic threshold for the decay of the heavier electroweakinos into the lightest neutralino. This decay mode provides also an alternative way of looking for heavy Higgs bosons in this range of masses and hence should be a high priority for future LHC analyses.

    hep-phhep-exJHEP(2020)·16 citations
22. 22*

    Search for Axionlike-Particle-Induced Prompt Gamma-Ray Emission from Extragalactic Core-Collapse Supernovae with the Fermi Large Area Telescope

    Manuel Meyer🇺🇸 · Tanja Petrushevska🇸🇮

    During a core-collapse supernova (SN), axionlike particles (ALPs) could be produced through the Primakoff process and subsequently convert into $\gamma$ rays in the magnetic field of the Milky Way. We do not find evidence for such a $\gamma$-ray burst in observations of extragalactic SNe with the Fermi Large Area Telescope (LAT). The SN explosion times are estimated from optical light curves and we find a probability of about $\sim$90% that the LAT observed at least one SN at the time of the core collapse. Under the assumption that at least one SN was contained within the LAT field of view, we exclude photon-ALP couplings $\gtrsim 2.6\times 10^{-11}$GeV${}^{-1}$ for ALP masses $m_a\lesssim 3\times 10^{-10}$ eV, within a factor of $\sim 5$ of previous limits from SN1987A.

    ↳ astro-ph.HEhep-phPRL(2020)·98 citations
23. 23*

    Breaking the Warp Barrier: Hyper-Fast Solitons in Einstein-Maxwell-Plasma Theory

    Erik W. Lentz🇩🇪

    Solitons in space--time capable of transporting time-like observers at superluminal speeds have long been tied to violations of the weak, strong, and dominant energy conditions of general relativity. The negative-energy sources required for these solitons must be created through energy-intensive uncertainty principle processes as no such classical source is known in particle physics. This paper overcomes this barrier by constructing a class of soliton solutions that are capable of superluminal motion and sourced by purely positive energy densities. The solitons are also shown to be capable of being sourced from the stress-energy of a conducting plasma and classical electromagnetic fields. This is the first example of hyper-fast solitons resulting from known and familiar sources, reopening the discussion of superluminal mechanisms rooted in conventional physics.

    ↳ gr-qcastro-ph.HEhep-phClass.Quant.Grav.(2021)·47 citations
24. 24*

    Quantifying the Line-of-Sight Halo Contribution to the Dark Matter Convergence Power Spectrum from Strong Gravitational Lenses

    Atınç Çağan Şengül🇺🇸 · Arthur Tsang🇺🇸 · Ana Diaz Rivero🇺🇸 · Cora Dvorkin (Harvard)🇺🇸 · Hong-Ming Zhu🇺🇸 · Uroš Seljak (Berkeley)🇺🇸

    Galaxy-galaxy strong gravitational lenses have become a popular probe of dark matter (DM) by providing a window into structure formation on the smallest scales. In particular, the convergence power spectrum of subhalos within lensing galaxies has been suggested as a promising observable to study DM. However, the distances involved in strong-lensing systems are vast, and we expect the relevant volume to contain line-of-sight (LOS) halos that are not associated with the main lens. We develop a formalism to calculate the effect of LOS halos as an effective convergence power spectrum. The multi-lens plane equation couples the angular deflections of consecutive lens planes, but by assuming that the perturbations due to the LOS halos are small, we show that they can be projected onto the main-lens plane as effective subhalos. We test our formalism by simulating lensing systems using the full multi-plane lens equation and find excellent agreement. We show how the relative contribution of LOS halos and subhalos depends on the source and lens redshift, as well as the assumed halo and subhalo mass functions. For a fiducial system with fraction of DM halo mass in substructure $f_{\mathrm{sub}}=0.4\%$ for subhalo masses $[10^5-10^8]{\mathrm{M}}_{\odot }$, the interloper contribution to the power spectrum is at least several times greater than that of subhalos for source redshifts $z_s\gtrsim 0.5$. Furthermore, it is likely that for the SLACS and BELLS lenses the interloper contribution dominates: $f_{\mathrm{sub}}\gtrsim 2\%$ ($4\%$) is needed for subhalos to dominate in SLACS (BELLS), which is higher than current upper bounds on $f_{\mathrm{sub}}$ for our mass range. Since the halo mass function is better understood from first principles, the dominance of interlopers in galaxy-galaxy lenses with high-quality imaging can be seen as a significant advantage when translating this observable into a constraint on DM.

    ↳ astro-ph.COhep-phPRD(2020)·40 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.