Wed·Dec 5, 2018Wednesday·December 5, 2018

1. 01*

   The Path to $0.01\%$ Theoretical Luminosity Precision for the FCC-ee

   S. Jadach🇵🇱 · W. Płaczek🇵🇱 · M. Skrzypek🇵🇱 · B.F.L. Ward🇺🇸 · S.A. Yost🇺🇸

   The current status of the theoretical precision for the Bhabha luminometry is critically reviewed and pathways are outlined to the requirement targeted by the FCC-ee precision studies. Various components of the pertinent error budget are discussed in detail -- starting from the context of the LEP experiments, through their current updates, up to prospects of their improvements for the sake of the FCC-ee. It is argued that with an appropriate upgrade of the Monte Carlo event generator BHLUMI and/or other similar MC programs calculating QED effects in the low angle Bhabha process, the total theoretical error of $0.01\%$ for the FCC-ee luminometry can be reached. A new study of the $Z$ and $s$-channel $\gamma$ exchanges within the angular range of the FCC-ee luminometer using the BHWIDE Monte Carlo was instrumental in obtaining the above result. Possible ways of BHLUMI upgrade are also discussed.

   hep-phPLB(2019)·42 citations
2. 02*

   Bjorken polarized sum rule and infrared-safe QCD couplings

   Cesar Ayala🇨🇱 · Gorazd Cvetic🇨🇱 · Anatoly V. Kotikov🇷🇺 · Binur G. Shaikhatdenov🇷🇺

   Experimental data obtained for the polarized Bjorken sum rule (BSR) ${\Gamma }_1^{p-n}(Q^2)$ are fitted by using predictions derived within a truncated operator product expansion (OPE) approach to QCD. Four QCD versions are considered: perturbative QCD (pQCD) in the MSbar scheme, Analytic Perturbation Theory (APT), and 2$\delta$ and 3$\delta$ analytic QCD versions. In contrast to pQCD, these QCD variants do not have Landau singularities at low positive $Q^2$, which facilitates the fitting procedure significantly. The fitting procedure is applied first to the experimental data of the inelastic part of BSR, and the known elastic contributions are added after the fitting. In general, when 2$\delta$ and 3$\delta$ QCD coupling is used the fitted curves give the best results, within the $Q^2$-range of the fit as well as in extended $Q^2$-intervals. When the fitting procedure is applied to the total BSR, i.e., to the sum of the experimental data and the elastic contribution, the quality of the results deteriorates significantly.

   hep-phEPJC(2018)·48 citations
3. 03*

   Chiral symmetry breaking corrections to the pseudoscalar pole contribution of the Hadronic Light-by-Light piece of $a_{\mu }$

   Adolfo Guevara🇪🇸 · Juan José Sanz Cillero🇪🇸 · Pablo Roig🇲🇽

   We have studied the $P\to {\gamma }^{\star }{\gamma }^{\star }$ form factor in Resonance Chiral Theory, with $P={\pi }^0\eta {\eta }^{\prime }$, to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic moment of the muon. In this work we allow the leading $U(3)$ chiral symmetry breaking terms, obtaining the most general expression for the form factor up to $\mathcal{O}(m_P^2)$. The parameters of the Effective Field Theory are obtained by means of short distance constraints on the form factor and matching with the expected behavior from QCD. Those parameters that cannot be fixed in this way are fitted to experimental determinations of the form factor within the spacelike region. Chiral symmetry relations among the transition form factors for ${\pi }^0,\eta$ and ${\eta }^{\prime }$ allow for a simultaneous fit to experimental data for the three mesons. This shows an inconsistency between the BaBar ${\pi }^0$ data and the rest of the experimental inputs. Thus, we find a total pseudoscalar pole contribution of $a_{\mu }^{P,HLbL}=(8.47\pm 0.16)\cdot 10^{-10}$ for our best fit (that neglecting the BaBar ${\pi }^0$ data). Also, a preliminary rough estimate of the impact of NLO in $1/N_C$ corrections and higher vector multiplets (asym) enlarges the uncertainty up to $a_{\mu }^{P,HLbL}=(8.47\pm 0.16_{\mathrm{stat}}\pm 0.09_{N_C}{}_{-0.0_{\mathrm{asym}}}^{+0.5})10^{-10}$.

   hep-phPoS(2018)·0 citations
4. 04*

   Interplay of dynamical and explicit chiral symmetry breaking effects on a quark

   Fernando E. Serna🇧🇷 · Chen Chen🇧🇷 · Bruno El-Bennich🇧🇷

   The relative contributions of explicit and dynamical chiral symmetry breaking in QCD models of the quark-gap equation are studied in dependence of frequently employed ansätze for the dressed interaction and quark-gluon vertex. The explicit symmetry breaking contributions are defined by a constituent-quark sigma term whereas the combined effects of explicit and dynamical symmetry breaking are described by a Euclidean constituent-mass solution. We extend this study of the gap equation to a quark-gluon vertex beyond the Abelian approximation complemented with numerical gluon- and ghost-dressing functions from lattice QCD. We find that the ratio of the sigma term over the Euclidean mass is largely independent of nonperturbative interaction and vertex models for current-quark masses, $m_{u,d}(\mu )\le m(\mu )\le m_b(\mu )$, and equal contributions of explicit and dynamical chiral symmetry breaking occur at $m(\mu )\approx 400$~MeV. For massive solutions of the gap equation with lattice propagators this value decreases to about 200~MeV.

   hep-phnucl-thPRD(2019)·30 citations
5. 05*

   Wigner function and pair production in parallel electric and magnetic fields

   Xin-li Sheng🇨🇳 · Ren-hong Fang🇨🇳 · Qun Wang🇨🇳 · Dirk H. Rischke🇩🇪

   We derive analytical formulas for the equal-time Wigner function in an electromagnetic field of arbitrary strength. While the magnetic field is assumed to be constant, the electric field is assumed to be space-independent and oriented parallel to the magnetic field. The Wigner function is first decomposed in terms of the so-called Dirac-Heisenberg-Wigner (DHW) functions and then the transverse-momentum dependence is separated using a new set of basis functions which depend on the quantum number $n$ of the Landau levels. Equations for the coefficients are derived and then solved for the case of a constant electric field. The pair-production rate for each Landau level is calculated. In the case of finite temperature and chemical potential, the pair-production rate is suppressed by Pauli's exclusion principle.

   hep-phPRD(2019)·50 citations
6. 06*

   Electroweak production of multiple (pseudo)scalars in the 2HDM

   Rikard Enberg🇸🇪 · William Klemm🇸🇪 · Stefano Moretti🇬🇧 · Shoaib Munir🇰🇷

   The two-Higgs Doublet Model (2HDM) is the most minimal extension of the Standard Model (SM) containing extra Higgs doublet fields. Given the multiplicity of Higgs states in a 2HDM, its Higgs potential is significantly more involved than the SM one. Importantly, it contains a multitude of Higgs triple self-couplings, unlike the SM, which only has one. These interactions are key to understanding the phenomenology of the 2HDM, as they uniquely determine the form of the potential. Several studies analysing the prospects of measuring these couplings at the Large Hadron Collider (LHC) have found them to be quite low generally. However, such studies have largely concentrated on Higgs pair-production induced by gluon-gluon scattering, either via direct annihilation or followed by their splitting into $b$-(anti)quark pairs, which in turn annihilate leaving behind spectator $b$-(anti)quarks. Both of these channels are therefore governed by QCD dynamics. We compare here the yields of such channels to those initiated by (primarily) valence quarks, which involve Electro-Weak (EW) interactions only, for neutral multi-Higgs final states. We find that EW production can be dominant over QCD production for certain final state combinations. We also illustrate that charged final states, which can only be produced via EW modes, could serve as important probes of some $H^{\pm }$ triple couplings, that are inaccessible in QCD-induced processes, during Run 2 and 3 of the LHC. Our analysis covers regions of the parameter space of the Type-I 2HDM that have escaped the most up-to-date experimental constraints coming from EW precision data, LHC measurements of the 125 GeV Higgs boson properties, searches for additional Higgs states, and flavour physics.

   hep-phEPJC(2019)·12 citations
7. 07*

   A two-component model for identified-hadron ${\mathbf{p}}_{\mathbf{t}}$ spectra from 5 TeV p-Pb collisions

   Thomas A. Trainor🇺🇸

   In preparation for the heavy ion program at the relativistic heavy ion collider (RHIC) $d$-Au collisions were designated as a control experiment for possible discovery of a quark-gluon plasma (QGP) in more-central Au-Au collisions, and contrasting results from the two systems seemed to support such a discovery. In contrast, recent results ($p_t$-spectrum and angular-correlation features) from $p$-Pb collisions at the large hadron collider (LHC) have been interpreted to support claims of hydrodynamic flows and QGP formation even in small collision systems. The present study addresses such claims via a two-component (soft + hard) model (TCM) of identified-hadron (PID) $p_t$ spectra from 5 TeV $p$-Pb collisions. $p$-Pb centrality is adopted from a previous study of ensemble-mean ${\bar{p}}_t$ data from the same system. $p$-Pb $p_t$ spectra for pions, kaons, protons and Lambdas are described by the TCM within their point-to-point uncertainties. Invariance of the TCM hard component vs $p$-Pb centrality indicates that jet formation remains unchanged in $p$-Pb collisions relative to $p$-$p$ collisions, and radial-flow contributions to spectra are negligible. These $p$-Pb TCM results have implications for interpretation of similar data features from A-A collisions in terms of QGP formation.

   hep-phJ.Phys.G(2020)·25 citations
8. 08*

   Parametrization of the Yukawa matrix in the scotogenic model and single-zero textures of the neutrino mass matrix

   Teruyuki Kitabayashi🇯🇵

   As the first topic, we propose a new parametrization of the complex Yukawa matrix in the scotogenic model. The new parametrization is compatible with the particle data group parametrization of the neutrino sector. Some analytical expressions for the neutrino masses with the new parametrization are shown. As the second topic, we consider the phenomenology of the socotogenic model with the one-zero-textures of the neutrino flavor mass matrix. One of the six patterns of the neutrino mass matrix is favorable for the real Yukawa matrix. On the other hand, for the complex Yukawa matrix, five of the six patterns are compatible with observations of the neutrino oscillations, dark matter relic abundance and branching ratio of the $\mu \to e\gamma$ process.

   hep-phInt.J.Mod.Phys.A(2019)·14 citations
9. 09*

   Final taus and initial state polarization signatures from effective interactions of Majorana neutrinos at future $e^{+}{e}^{-}$ colliders

   Lucía Duarte🇺🇾 · Gabriel Zapata🇦🇷 · Oscar A. Sampayo🇦🇷

   We study the possibility of future $e^{+}{e}^{-}$ colliders to disentangle different new physics contributions to the production of heavy sterile Majorana neutrinos in the lepton number violating channel $e^{+}{e}^{-}\to l^{+}{l}^{+}+4jets$, with $l=e,\mu ,\tau$. This is done investigating the final anti-tau polarization trails and initial beam polarization dependence of the signal on effective operators with distinct Dirac-Lorentz structure contributing to the Majorana neutrino production and decay, which parameterize new physics from a higher energy scale. We find both analyses could well disentangle possible vectorial and scalar operators contributions.

   hep-phEPJC(2019)·18 citations
10. 10*

    A neutrino mass model with hidden $U(1)$ gauge symmetry

    Haiying Cai🇰🇷 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇰🇷

    We propose a realisation of inverse seesaw model controlled by hidden $U(1)$ gauge symmetry, and discuss the impact of a bosonic dark matter (DM) candidate by imposing a $Z_2$ parity. We present the detail of scalar spectra and apply the Casas-Ibarra parametrisation to fit the neutrino oscillation data. For this model, the allowed region is extracted to explain the observed relic density and the muon $g-2$ discrepancy, satisfying flavor constraints with DM involved. We interpret the DM annihilation into $\bar{f}f$ including all SM charged fermions and investigate the direct detection to place the bound on DM-Higgs coupling. Finally the LHC DM production is explored in light of charged lepton pair signature plus missing transverse energy.

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

    Quark binding potential and QGP

    Shukla Pal🇮🇳 · Aparajita Bhattacharya🇮🇳 · Ballari Chakrabarti🇮🇳 · Rismita Ghosh🇮🇳

    The effect of quark-antiquark potential on the dissociation energy and critical screening length of heavy meson like $b\overline{b}$ and $c\overline{c}$ have been investigated when the respective meson is in quark Gluon Plasma(QGP). The different types of interquark potential have been used which get screened in the QGP medium. The dissociation energy and critical screening length have been studied for both ground and excited states. It has been observed that the form of interquark potential has substantial effect on the critical screening length when the meson is in QGP. A comparison with other theoretical studies are made.

    hep-phActa Phys.Polon.B(2018)·1 citation
12. 12*

    Double parton scattering effects in heavy meson production

    Rafal Maciula

    We present results of our theoretical investigation of double-parton scattering (DPS) effects in production of heavy flavour mesons (charm and bottom). We discuss production of charm-bottom and bottom-bottom meson-meson pairs in proton-proton collisions at the LHC. The calculation of DPS mechanism is performed within factorized ansatz where each parton scattering is calculated in the framework of the $k_T$-factorization. The hadronization is done with the help of independent parton fragmentation picture. For completeness we compare results for double- and single-parton scattering (SPS). As in the case of double charm production also here the DPS dominates over the SPS, especially for small transverse momenta. We present several distributions and integrated cross sections with realistic cuts for simultaneous production of $D^0{B}^{+}$ and $B^{+}{B}^{+}$, suggesting future experimental studies at the LHCb detector.

    hep-ph0 citations
13. 13*

    Roberge-Weiss transitions at different center symmetry breaking patterns in a ${\mathbb{Z}}_3$-QCD model

    Xiu-Fei Li🇨🇳 · Zhao Zhang🇨🇳

    We study how the Roberge-Weiss (RW) transition depends on the pattern of center symmetry breaking using a ${\mathbb{Z}}_3$-QCD model. We adopt flavor-dependent quark imaginary chemical potentials, namely $({\mu }_u,{\mu }_d,{\mu }_s)/iT=(\theta -2\pi C/3,\theta ,\theta +2\pi C/3)$ with $C\in [0,1]$. The RW periodicity is guaranteed and the center symmetry of ${\mathbb{Z}}_3$-QCD is explicitly broken when $C\ne 1$ or/and quark masses are non-degenerate. For $N_f=3$ and $C\ne 1$, the RW transition occurs at $\theta ={\theta }_{RW}=(2k+1)\pi /3(k\in \mathbb{Z})$, which becomes stronger with decrease of $C$. When $C=1$, the ${\theta }_{RW}$ turns into $2k\pi /3$ for $N_f=2+1$, but keeps $(2k+1)\pi /3$ for $N_f=1+2$; in both cases, the RW transitions get stronger with the mass mismatch. For other $C\ne 0$ cases, the ${\theta }_{RW}$'s are not integral multiples of $\pi /3$. We find that the RW transition is more sensitive to the deviation of $C$ from one compared to the mass non-degeneracy and thus the strength of the traditional RW transition with $C=0$ is the strongest. The nature of RW endpoints and its implications to deconfinement transition are investigated.

    hep-phPRD(2019)·4 citations
14. 14*

    QCD phase diagram with chiral imbalance in NJL model: duality and lattice QCD results

    T. G. Khunjua🇷🇺 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺

    In addition to temperature and baryon chemical potential there are other parameters that matter in the real quark matter. One of them is isospin asymmetry which does exist in nature, for example, in the compact stars and in heavy ion collisions. The chiral imbalance, the difference between left- and right-handed quarks, is another phenomenon that could occur in quark matter. We have shown that lattice QCD results support the existence of the approximate duality in real QCD. The rise of pseudo-critical temperature with increase of chiral chemical potential ${\mu }_5$ (the much debated effect recently, a lot of studies on this contradict each other) has been established in terms of just duality notion, hence reinforce confidence in this result and put it on the considerably more solid ground.

    hep-phhep-lathep-thJ.Phys.Conf.Ser.(2019)·16 citations
15. 15*

    Bounds on the Equation of State of Neutron Stars from High Energy Deeply Virtual Exclusive Experiments

    Abha Rajan🇺🇸 · Tyler Gorda🇫🇮 · Simonetta Liuti🇺🇸 · Kent Yagi🇺🇸

    The recent detection of gravitational waves from merging neutron star events has opened a new window on the many unknown aspects of their internal dynamics. A key role in this context is played by the transition from baryon to quark matter described in the neutron star equation of state (EoS). In particular, the binary pulsar observation of heavy neutron stars requires appropriately stiff dense matter in order to counter gravitational collapse, at variance with the predictions of many phenomenological quark models. On the other side, the LIGO observations favor a softer EoS therefore providing a lower bound to the equation stiffness. We introduce a quantum chromodynamics (QCD) description of the neutron star's high baryon density regime where the pressure and energy density distributions are directly obtained from the matrix elements of the QCD energy momentum tensor. Recent ab initio calculations allow us to evaluate the energy-momentum tensor in a model independent way including both quark and gluon degrees of freedom. Our approach is a first effort to replace quark models and effective gluon interactions with a first principles, fully QCD-based description. Most importantly, the QCD energy momentum tensor matrix elements are connected to the Mellin moments of the generalized parton distributions which can be measured in deeply virtual exclusive scattering experiments. As a consequence, we establish a connection between observables from high energy experiments and from the analysis of gravitational wave events. Both can be used to mutually constrain the respective sets of data. In particular, the emerging QCD-based picture is consistent with the GW170817 neutron star merger event once we allow a first-order phase transition from a low-density nuclear matter EoS to the newly-constructed high-density quark-gluon one.

    hep-phastro-ph.COgr-qchep-lat+114 citations
16. 16*

    Kira 1.2 Release Notes

    Philipp Maierhöfer🇩🇪 · Johann Usovitsch🇮🇪

    We present the Feynman integral reduction program Kira 1.2 and describe its new features and other changes w.r.t. the previous versions. The main new features include a much faster equation generator, more flexible seed specification options, several predefined integral orderings, the reduction of systems of user-provided equations and a new technique to simplify coefficients by sampling variables over integers. Furthermore, we provide a collection of recommendations on how to use the program efficiently. This version has overall improvements in runtime for all reduction tasks compared to the previous versions of Kira.

    hep-ph112 citations
17. 17*

    Lectures on nonperturbative QCD ( Nonperturbative Topological Phenomena in QCD and Related Theories)

    Edward Shuryak🇺🇸

    These are lecture notes, which summarize the current status of the Semiclassical theory, as well as Monopoles, Instantons, Instanton-dyons and Flux tubes. The emphasis is on QCD and QCD-like theories (deformed QCD), although relevant points derived in Supersymmetric theories are also covered. While the actual lectures on which the notes are based were delivered in the fall 2018, the text evolved over the years and summarizes about 4 decades of development. One recent point added is the so called Poisson duality between monopoles and instanton-dyon approaches. It is made in a book format, with extensive list of references. Large size of the text have lead to many imperfections, which I hope to correct in future versions.

    hep-ph26 citations
18. 18*

    Polynomiality sum rules for generalized parton distributions of spin-1 targets

    W. Cosyn🇧🇪 · A. Freese🇺🇸 · B. Pire🇫🇷

    We present the polynomiality sum rules for all leading-twist quark and gluon generalized parton distributions (GPDs) of spin-1 targets such as the deuteron nucleus. The sum rules connect the Mellin moments of these GPDs to polynomials in skewness parameter $\xi$, which contain generalized form factors (GFFs) as their coefficients. The decompositions of local currents in terms of generalized form factors for spin-1 targets are obtained as a byproduct of this derivation.

    hep-phnucl-thPRD(2019)·19 citations
19. 19*

    Supersymmetric sphaleron configurations as the origin of the perplexing ANITA events

    Luis A. Anchordoqui🇺🇸 · Ignatios Antoniadis🇫🇷

    The ANITA experiment has observed two air shower events with energy ~ 500 PeV emerging from the Earth with exit angles of ~ 30 degrees. We explain ANITA events as arising from neutrino-induced supersymmetric sphaleron transitions. These high-multiplicity configurations could contain a large number of long-lived supersymmetric fermions, which can traverse the Earth and decay in the atmosphere to initiate upward-pointing air showers at large angles above the horizon. We comment on the sensitivity of new generation LHC detectors, designed to searching for displaced decays of beyond standard model long-lived particles, to test our model.

    hep-phastro-ph.HEPLB(2019)·35 citations
20. 20*

    Composite Higgs Models: a new holographic approach

    Domenec Espriu🇪🇸 · Alisa Katanaeva🇪🇸

    We revisit the construction of the composite Higgs models in a context of the bottom-up holographic approach. The soft wall framework is under consideration imposing the translation of the $4D$ global symmetry breaking characteristic to the new strongly interacting sector in the $5D$ bulk. The focus stays on the minimal $SO(5)\to SO(4)$ breaking pattern. The $5D$ model has a specific form inspired by the effective models of QCD, representing a generalized sigma model coupled both to the composite resonances and to the SM gauge bosons. The latter are treated as external $4D$ sources and conceptually develop no propagation into the bulk. The holographic description allows for the consideration of spin one and spin zero resonances. The resulting spectrum leads in a natural way to a variety of new composite resonances, four of which represent the massless Goldstone bosons. Existing experimental constraints on the electroweak precision parameters permit to accommodate vector and scalar resonances with masses in the $1-2$ TeV range without difficulties, but higher masses are possible too. Moreover, for the SM gauge fields holography provides relevant vacuum polarization amplitudes and mixing with composite resonances. Further considering higher order correlation functions we can formulate semi-quantitative predictions for the effective couplings and cross-sections. These provide additional restrictions that are currently being investigated.

    hep-phhep-thPoS(2018)·2 citations
21. 21*

    Closing the light gluino gap with electron-proton colliders

    David Curtin🇨🇦 · Kaustubh Deshpande🇺🇸 · Oliver Fischer🇩🇪 · Jose Zurita🇩🇪

    The future electron-proton collider proposals, LHeC and FCC-he, can deliver $\mathcal{O}$(TeV) center-of-mass energy collisions, higher than most of the proposed lepton accelerators, with $\mathcal{O}$(ab${}^{-1}$) luminosity, while maintaining a much cleaner experimental environment as compared to the hadron machines. This unique capability of $e^{-}p$ colliders can be harnessed in probing BSM scenarios giving final states that look like hadronic noise at $pp$ machines. In the present study, we explore the prospects of detecting such a prompt signal having multiple soft jets at the LHeC. Such a signal can come from the decay of gluino in RPV or Stealth SUSY, where there exists a gap in the current experimental search with $m_{\tilde{g}}\approx 50-70$ GeV. We perform a simple analysis to demonstrate that, with simple signal selection cuts, we can close this gap at the LHeC at 95 % confidence level, even in the presence of a reasonable systematic error. More sophisticated signal selection strategies and detailed knowledge of the detector can be used to improve the prospects of signal detection.

    hep-phPRD(2019)·5 citations
22. 22*

    Direct measurement of the Higgs self-coupling in $e^{+}{e}^{-}\to ZH$

    Junya Nakamura🇩🇪 · Ambresh Shivaji🇧🇪

    A new method to measure the trilinear Higgs self-coupling ${\lambda }_3^{}$ in a single Higgs production process is proposed. Time-reversal-odd (T-odd) asymmetries in the process $e_{}^{+}{e}_{}^{-}\to ZH$, $Z\to f\bar{f}$ are computed from the absorptive part of the electroweak one-loop amplitude. Since the T-odd asymmetries measure the tree-level $t$-channel $ZH\to ZH$ scattering, they can be direct probes of ${\lambda }_3^{}$. The proposed method is quite challenging; a relatively large statistics and polarized $e_{}^{+}{e}_{}^{-}$ beams are demanded. However, this is probably the only approach to directly measure ${\lambda }_3^{}$ in $e_{}^{+}{e}_{}^{-}$ collisions, when a beam energy above the $ZHH$ production threshold is not available.

    hep-phPLB(2019)·7 citations
23. 23*

    Renormalon-motivated evaluation of QCD observables

    Gorazd Cvetic🇨🇱

    A method of evaluation of spacelike QCD observables $\mathcal{D}(Q^2)$ is developed, motivated by the renormalon structure of these quantities. A related auxiliary quantity $\tilde{\mathcal{D}}(Q^2)$ is introduced, which is renomalization scale independent only at the one-loop level, and a large-${\beta }_0$-type renormalon motivated ansatz is made for the Borel transform of this quantity. This leads to a `dressed' Borel transform of the considered observable $\mathcal{D}(Q^2)$. From there, a Neubert-type distribution is obtained for the observable. The described method is then applied to the massless Adler function and the related decay ratio of the $\tau$ lepton semihadronic decays. Comparisons are then made with an evaluation method at higher truncated orders, developed in our earlier works, which is a renormalization scale invariant extension of the diagonal Padé approximants.

    hep-phPRD(2019)·34 citations
24. 24*

    Constraints on New Scalar and Vector Mediators from LHC Dijet Searches

    Sebastian Baum🇸🇪 · Riccardo Catena🇸🇪 · Martin B. Krauss🇸🇪

    We present a reanalysis of the latest results from CMS dijet searches for an integrated luminosity of $36$fb${}^{-1}$ together with preliminary results for $78$fb${}^{-1}$ in the framework of simplified models for dark matter interacting with quarks through the exchange of a scalar, pseudoscalar, vector or pseudovector mediator particle. Within the same framework, we also project the sensitivity of dijet searches in future LHC runs and study how well the parameters of a simplified model could be reconstructed in case of a future discovery at the high luminosity (HL) LHC. Finally, we explore the possibility of discriminating different mediator scenarios by extending the sensitivity of dijet searches for simplified models through the use of angular information. It is the first time that these studies are performed systematically for the case of spin 0 mediators. Among other results we find: 1) no evidence for a dijet signal in the simplified model framework; 2) improvements due to an increased luminosity at the HL-LHC are significant, but mostly for heavy mediators, where dijet searches are limited by statistical, rather than systematical uncertainties; 3) Information on the angular separation of dijets could be used at the HL-LHC to discriminate different mediator scenarios.

    hep-phJ.Phys.G(2020)·6 citations
25. 25*

    Impact of a XENONnT Signal on LHC Dijet Searches

    Sebastian Baum🇸🇪 · Riccardo Catena🇸🇪 · Martin B. Krauss🇸🇪

    It is well-known that dark matter (DM) direct detection experiments and the LHC are complementary, since they probe physical processes occurring at different energy scales. And yet, there are aspects of this complementarity which are still not fully understood, or exploited. For example, what is the impact that the discovery of DM at XENONnT would have on present and future searches for DM in LHC final states involving a pair of hadronic jets? In this work we investigate the impact of a XENONnT signal on the interpretation of current dijet searches at the LHC, and on the prospects for dijet signal discovery at the High-Luminosity (HL) LHC in the framework of simplified models. Specifically, we focus on a general class of simplified models where DM can have spin 0, 1/2 or 1, and interacts with quarks through the exchange of a scalar, pseudo-scalar, vector, or pseudo-vector mediator. We find that exclusion limits on the mediator's mass and its coupling to quarks from dijet searches at the LHC are significantly affected by a signal at XENONnT, and that $\mathcal{O}(100)$ signal events at XENONnT would drastically narrow the region in the parameter space of simplified models where a dijet signal can be discovered at $5\sigma$ C.L. at the HL-LHC.

    hep-phJHEP(2019)·7 citations
26. 26*

    Dark matter stability and Dirac neutrinos using only Standard Model symmetries

    Cesar Bonilla🇩🇪 · Salvador Centelles Chuliá🇪🇸 · Ricardo Cepedello🇪🇸 · Eduardo Peinado🇲🇽 · Rahul Srivastava🇪🇸

    We provide a generic framework to obtain stable dark matter along with naturally small Dirac neutrino masses generated at the loop level. This is achieved through the spontaneous breaking of the global $U(1{)}_{B-L}$ symmetry already present in Standard Model. The $U(1{)}_{B-L}$ symmetry is broken down to a residual even ${\mathcal{Z}}_n$; $n\ge 4$ subgroup. The residual ${\mathcal{Z}}_n$ symmetry simultaneously guarantees dark matter stability and protects the Dirac nature of neutrinos. The $U(1{)}_{B-L}$ symmetry in our setup is anomaly free and can also be gauged in a straightforward way. Finally, we present an explicit example using our framework to show the idea in action.

    hep-phPRD(2020)·87 citations
27. 27*

    Left-Right SU(4) Vector Leptoquark Model for Flavor Anomalies

    Bartosz Fornal🇺🇸 · Sri Aditya Gadam🇺🇸 · Benjamin Grinstein🇺🇸

    Building on our recent proposal to explain the experimental hints of new physics in $B$ meson decays within the framework of Pati-Salam quark-lepton unification, through the interactions of the $(3,1{)}_{2/3}$ vector leptoquark, we construct a realistic model of this type based on the gauge group $\mathrm{SU}(4{)}_L\times \mathrm{SU}(4{)}_R\times \mathrm{SU}(2{)}_L\times \mathrm{U}(1{)}^{\prime }$ and consistent with all experimental constraints. The key feature of the model is that $\mathrm{SU}(4{)}_R$ is broken at a high scale, which suppresses right-handed lepton flavor changing currents at the low scale and evades the stringent bounds from searches for lepton flavor violation. The mass of the leptoquark can be as low as $10\mathrm{TeV}$ without the need to introduce mixing of quarks or leptons with new vector-like fermions. We provide a comprehensive list of model-independent bounds from low energy processes on the couplings in the effective Hamiltonian that arises from generic leptoquark interactions, and then apply these to the model presented here. We discuss various meson decay channels that can be used to probe the model and we investigate the prospects for discovering the new gauge boson at future colliders.

    hep-phPRD(2019)·115 citations
28. 28*

    Excited mesons, baryons, glueballs and tetraquarks: Predictions of the Holography Inspired Stringy Hadron model

    Jacob Sonnenschein🇮🇱 · Dorin Weissman🇮🇱

    In this note we collect and summarize the predictions of the Holography Inspired Stringy Hadron (HISH) model. We list the masses and widths of predicted excited states across the spectrum, based on placing the different hadrons on the non-linear Regge trajectories of a string with massive endpoints. Our predicted states include: (i) Light, heavy-light and heavy-heavy mesons. (ii) Baryons, including charmed, doubly charmed and bottom baryons. (iii) Glueballs, together with a method to disentangle them from flavorless mesons. (iv) Genuine tetraquarks, which are not "molecules" of hadrons, and are characterized by their decay into a baryon and an anti-baryon.

    hep-phhep-exhep-thEPJC(2019)·47 citations
29. 29*

    Transmutation of nonlocal scale in infinite derivative field theories

    Luca Buoninfante🇮🇹 · Anish Ghoshal🇮🇹 · Gaetano Lambiase🇮🇹 · Anupam Mazumdar🇳🇱

    In this paper we will show an ultraviolet -infrared connection for ghost-free infinite derivative field theories where the Lagrangians are made up of exponentials of entire functions. In particular, for $N$-point amplitudes a new scale emerges in the infrared from the ultraviolet, i.e. $M_{\mathrm{eff}}\sim M_s/N^{\alpha },$ where $M_s$ is the fundamental scale beyond the Standard Model, and $\alpha >0$ depends on the specific choice of an entire function and on whether we consider zero or nonzero external momenta. We will illustrate this by first considering a scalar toy model with a cubic interaction, and subsequently a scalar toy-model inspired by ghost-free infinite derivative theories of gravity. We will briefly discuss some phenomenological implications, such as making the nonlocal region macroscopic in the infrared.

    ↳ hep-thgr-qchep-phPRD(2019)·54 citations
30. 30*

    Dipole-dipole interactions between neutrons

    Renato Higa🇧🇷 · James F. Babb🇺🇸 · Mahir S. Hussein🇧🇷

    In this work we present results of the dipole-dipole interactions between two neutrons, a neutron and a conducting wall, and a neutron between two walls. As input, we use dynamical electromagnetic dipole polarizabilities fitted to chiral EFT results up to the pion production threshold and at the onset of the Delta resonance. Our work can be relevant to the physics of confined ultracold neutrons inside bottles.

    ↳ nucl-thhep-phnucl-exSpringer Proc.Phys.(2020)·1 citation
31. 31*

    Two-integral distribution functions in axisymmetric galaxies: implications for dark matter searches

    Mihael Petac🇮🇹 · Piero Ullio🇮🇹

    We address the problem of reconstructing the phase-space distribution function for an extended collisionless system, with known density profile and in equilibrium within an axisymmetric gravitational potential. Assuming that it depends on only two integrals of motion, namely the energy and the component of the angular momentum along the axis of symmetry $L_z$, there is a one-to-one correspondence between the density profile and the component of the distribution function that is even in $L_z$, as well as between the weighted azimuthal velocity profile and the odd component. This inversion procedure was originally proposed by Lynden-Bell and later refined in its numerical implementation by Hunter & Qian; after overcoming a technical difficulty, we apply it here for the first time in presence of a strongly flattened component, as a novel approach of extracting the phase-space distribution function for dark matter particles in the halo of spiral galaxies. We compare results obtained for realistic axisymmetric models to those in the spherical symmetric limit as assumed in previous analyses, showing the rather severe shortcomings in the latter. We then apply the scheme to the Milky Way and discuss the implications for the direct dark matter searches. In particular, we reinterpret the null results of the Xenon1T experiment for spin-(in)dependent interactions and make predictions for the annual modulation of the signal for a set of axisymmetric models, including a self-consistently defined co-rotating halo.

    ↳ astro-ph.GAhep-phPRD(2019)·15 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.