HEP Phenomenology·hep-ph

Fri·Dec 7, 2018Friday·December 7, 2018

35 papers—27 primary·8 cross-listed·reconstructed*

01*
Predicting Alignment in a Two Higgs Doublet Model
Karim Benakli🇫🇷 · Yifan Chen🇫🇷 · Gaëtan Lafforgue-Marmet🇫🇷
We show that a non-abelian global $S U (2)_{R}$ acting on the quartic part of the two Higgs Doublet Model leads, at tree-level, to an automatic alignment without decoupling. An example of phenomenologically viable model with this feature is the the low energy effective field theory of the Minimal Dirac Gaugino Supersymmetric Model in the limit where the adjoint scalars are decoupled. We discuss here how the $S U (2)_{R}$ can be identified with the R-symmetry of the $N = 2$ supersymmetry in the gauge and Higgs sectors. We also review how the radiative corrections lead to a very small misalignment.
hep-phMDPI Proc.(2019)·4 citations
02*
Quarkonium production in heavy ion collisions: coupled Boltzmann transport equations
Xiaojun Yao🇺🇸 · Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen Bass🇺🇸 · Berndt Müller🇺🇸
By coupling the Boltzmann transport equations of both quarkonium and open heavy quarks, we investigate their dynamical evolution inside the quark-gluon plasma and study quarkonium production in heavy ion collisions. The Boltzmann transport equation of quarkonium is derived from the open quantum system formalism and effective field theory of QCD by assuming quarkonium interacts weakly with the plasma. The dissociation and recombination terms in the Boltzmann equation are calculated in potential nonrelativistic QCD. It is shown that the combination of quarkonium dissociation, recombination, open heavy quark diffusion and energy loss can drive the system of quarkonium and open heavy quarks to detailed balance and kinetic thermalization. By solving the transport equations with initial momenta of quarkonia and heavy quarks sampled from PYTHIA and a hydrodynamic medium, we can calculate the nuclear modification factors of bottomonium and describe the data at both RHIC and LHC energies. The azimuthal angular anisotropy coefficient $v_{2}$ of $Υ$ (1S) in 5.02 TeV peripheral Pb-Pb collisions is also predicted.
hep-phnucl-thPoS(2018)·7 citations
03*
Atmospheric Charm, QCD and Neutrino Astronomy
Michael Benzke🇩🇪 · Maria V. Garzelli🇩🇪 · Bernd A. Kniehl🇩🇪
We present predictions for the prompt-neutrino flux arising from the decay of charmed mesons and baryons produced by the interactions of high-energy cosmic rays in the Earth's atmosphere, making use of a QCD approach on the basis of the general-mass variable-flavor-number scheme for the description of charm hadroproduction at next-to-leading order, complemented by a consistent set of fragmentation functions. This same scheme is used for the description of charm hadroproduction at both the Tevatron and the Large Hadron Collider. We compare the theoretical predictions to those already obtained by our and other groups with different theoretical approaches. We provide comparisons with the experimental results obtained by the IceCube Collaboration and we discuss implications for parton distribution functions.
hep-phastro-ph.HEPoS(2018)·1 citation
04*
Cosmological Perturbations in a Universe with a Domain Wall Era
Cyrus Faroughy🇺🇸
Topologically protected sheet-like surfaces, called domain walls, form when the potential of a field has a discrete symmetry that is spontaneously broken. Since this condition is commonplace in field theory, it is plausible that many of these walls were produced at some point in the early universe. Moreover, for potentials with a rich enough structure, the walls can join and form a (at large scales) homogeneous and isotropic network that dominates the energy density of the universe for some time before decaying. In this thesis, we study the faith of large scale perturbations in a cosmology with a short period of domain wall dominance. Treating the domain wall network as a relativistic elastic solid at large scales, we show that the perturbations that exited the horizon during inflation get suppressed during the domain wall era, before re-entering the horizon. This power suppression occurs because, unlike a fluid-like universe, a solid-like universe can support sizable anisotropic stress gradients across large scales which effectively act as mass for the scalar and tensor modes. Interestingly, the amplitude of the primordial scalar power spectrum can be closer to one in this cosmology and still give the observed value of $1 0^{- 9}$ today. As a result, the usual bounds on the energy scale of inflation get relaxed to values closer to the (more natural) Planck scale. In the last part of this thesis, as an existence proof, we present a hybrid inflation model with $N$ `waterfall' fields that can realize the proposed cosmology. In this model, a domain wall network forms when an approximate $O (N)$ symmetry gets spontaneously broken at the end of inflation, and for $N \geq 5$ , we show that there is a region in parameter space where the network dominates the energy density for a few e-folds before decaying and reheating the universe.
hep-phgr-qc1 citation
05*
CP Properties of Leptons in Mirror Mechanism
Igor T. Dyatlov🇷🇺
Formation of quark and lepton mass matrices through intermediate states of heavy mirror fermions is capable of reproducing main qualitative properties of weak mixing matrices (CKM and PMNS matrices). The reproduction includes the hierarchy of CKM matrix elements, a general form of the PMNS matrix, involving the smallness of the neutrino mixing angle \theta_{13}, and leads to very small neutrino masses. For leptons, these properties appear only for the Dirac nature of SM neutrino and its inverse spectrum. In such a lepton system, not only do spontaneous mirror symmetry violation and the observed mass hierarchy of charged leptons (e,\mu,\tau) govern the structure of the PMNS matrix but also permit assessment of its allowed complexity, that is, the CP properties of leptons. The PMNS matrix then contains no Majorana phases and its Dirac phase \delta_{CP} corresponds to |\sin\delta_{CP}|, which is significantly smaller than unity.
hep-phhep-exPhys.Atom.Nucl.(2019)·1 citation
06*
The simple interpretations of lepton anomalies in the lepton-specific inert two-Higgs-doublet model
Xiao-Fang Han🇨🇳 · Tianjun Li🇨🇳 · Lei Wang🇨🇳 · Yang Zhang🇦🇺
There exist about $3.7 σ$ positive and $2.4 σ$ negative deviations in the muon and electron anomalous magnetic moments ( $g - 2$ ). Also, some ratios for lepton universality in $τ$ decays have almost $2 σ$ deviations from the Standard Model. In this paper, we propose a lepton-specific inert two-Higgs-doublet model. After imposing all the relevant theoretical and experimental constraints, we show that these lepton anomalies can be explained simultaneously in many parameter spaces with $m_{H} > 200$ GeV and $m_{A} (m_{H^{\pm}}) > 500$ GeV for appropriate Yukawa couplings between leptons and inert Higgs. The key point is that these Yukawa couplings for $μ$ and $τ$ / $e$ have opposite sign.
hep-phPRD(2019)·89 citations
07*
Photon-Photon Scattering at the High-Intensity Frontier: Paraxial Beams
Alexander Blinne🇩🇪 · Holger Gies🇩🇪 · Felix Karbstein🇩🇪 · Christian Kohlfürst🇩🇪 · Matt Zepf🇩🇪
Our goal is to study optical signatures of quantum vacuum nonlinearities in strong macroscopic electromagnetic fields provided by high-intensity laser beams. The vacuum emission scheme is perfectly suited for this task as it naturally distinguishes between incident laser beams, described as classical electromagnetic fields driving the effect, and emitted signal photons encoding the signature of quantum vacuum nonlinearity. Using the Heisenberg-Euler effective action, our approach allows for a reliable study of photonic signatures of QED vacuum nonlinearity in the parameter regimes accessible by all-optical high-intensity laser experiments. To this end, we employ an efficient, flexible numerical algorithm, which allows for a detailed study of the signal photons emerging in the collision of focused paraxial high-intensity laser pulses. Due to the high accuracy of our numerical solutions we predict the total number of signal photons, but also have full access to the signal photons' characteristics, including their spectrum, propagation directions and polarizations. We discuss setups offering an excellent background-to-noise ratio, thus providing an important step towards the experimental verification of quantum vacuum nonlinearities.
hep-phphysics.opticsquant-phJ.Phys.Conf.Ser.(2019)·5 citations
08*
LHC as a photon-photon collider
M. I. Vysotsky🇷🇺 · E. V. Zhemchugov🇷🇺
Equivalent photon approximation is used to calculate fiducial cross sections for dimuon production in ultraperipheral proton-proton and lead-lead collisions. Analytical formulae taking into account experimental cuts are derived. The results are compared with the measurements reported by the ATLAS collaboration.
hep-phhep-ex5 citations
09*
On separate chemical freeze-outs of hadrons and light (anti)nuclei in high energy nuclear collisions
K. A. Bugaev🇺🇦 · B. E. Grinyuk🇺🇦 · A. I. Ivanytskyi🇺🇦 · V. V. Sagun🇺🇦 · D. O. Savchenko🇺🇦 · G. M. Zinovjev🇺🇦 · E. G. Nikonov🇷🇺 · L. V. Bravina🇳🇴 · E. E. Zabrodin🇳🇴 · D. B. Blaschke🇵🇱 · S. Kabana🇫🇷 · A. V. Taranenko🇷🇺
The multiplicities of light (anti)nuclei were measured recently by the ALICE collaboration in Pb+Pb collisions at the center-of-mass collision energy $s_{N N} = 2.76$ TeV. Surprisingly, the hadron resonance gas model is able to perfectly describe their multiplicities under various assumptions. For instance, one can consider the (anti)nuclei with a vanishing hard-core radius (as the point-like particles) or with the hard-core radius of proton, but the fit quality is the same for these assumptions. In this paper we assume the hard-core radius of nuclei consisting of $A$ baryons or antibaryons to follow the simple law $R (A) = R_{b} (A)^{\frac{1}{3}}$ , where $R_{b}$ is the hard-core radius of nucleon. To implement such a relation into the hadron resonance gas model we employ the induced surface tension concept and analyze the hadronic and (anti)nuclei multiplicities measured by the ALICE collaboration. The hadron resonance gas model with the induced surface tension allows us to verify different scenarios of chemical freeze-out of (anti)nuclei. It is shown that the most successful description of hadrons can be achieved at the chemical freeze-out temperature $T_{h} = 150$ MeV, while the one for all (anti)nuclei is $T_{A} = 168.5$ MeV. Possible explanations of this high temperature of (anti)nuclei chemical freeze-out are discussed.
hep-phJ.Phys.Conf.Ser.(2019)·10 citations
10*
Collinearly improved kernel suppresses Coulomb tails in the impact-parameter dependent Balitsky-Kovchegov evolution
J. Cepila🇨🇿 · J. G. Contreras🇨🇿 · M. Matas🇨🇿
We solved the impact-parameter dependent Balitsky-Kovchegov equation with the recently proposed collinearly imporved kernel. We find that the solutions do not present the Coulomb tails that have affected previous studies. We also show that once choosing an adequate initial condition it is possible to obtain a reasonable description of HERA data on the structure function of the proton, as well as on the cross section for the exclusive production of a $J/ ψ$ vector meson off proton targets. As a further application of the solutions, we computed the impact-parameter dependent Weiszäcker-Williams gluon distribution.
hep-phPRD(2019)·51 citations
11*
Flavor mixing inspired by flipped SU(5) GUT
Junu Jeong🇰🇷 · Jihn E. Kim🇰🇷 · Se-Jin Kim
We obtain a phenomenologically acceptable Cabibbo-Kobayashi-Maskawa matrix in a flipped SU(5) model inspired by the compactification of heterotic string $E_{8} \times E_{8}^{'}$ .
hep-ph3 citations
12*
Signature of 2HDM at Higgs Factories
Wenhai Xie🇨🇳 · R. Benbrik🇲🇦 · Abdeljalil Habjia🇲🇦 · Souad Taj🇲🇦 · Bin Gong🇨🇳 · Qi-Shu Yan🇨🇳
The full one-loop corrections, both the weak and QED corrections, to the process $e^{+} e^{-} \to Z ϕ$ ( $ϕ = h^{0}, H^{0}$ ) in the two Higgs doublet model (2HDM) at the Higgs factories are presented. Up to the $O (α_{e m})$ level, the virtual corrections are evaluated by using the FeynArts/FormCalc packages. The real emission corrections are computed using the Feynman Diagram Calculation (FDC) package and the collinear divergences are regularized by the structure functions of an electron. Using the FeynArts/FormCalc and the FDC packages, we study the corrections in the Standard Model (SM) and the 2HDM, respectively. Gauge dependence arising in the normalization of mixing angles is removed by using the pinch technique. After taking into account experimental constraints from the current LHC data, we propose four interesting benchmark scenarios for future colliders. By using these benchmark scenarios, we evaluate the deviation of $Δ σ (e^{+} e^{-} \to Z ϕ)$ from their SM values. We also examine Higgs boson decays $ϕ \to b b ˉ$ and $ϕ \to τ^{+} τ^{-}$ , which can have large electroweak (EW) contributions from triple Higgs couplings which are absent in the SM. It is found that for these benchmark scenarios, both EW and real emission corrections are sizeable and could be measured at a future $e^{+} e^{-}$ colliders such as the ILC, CLIC, and CEPC.
hep-phPRD(2021)·23 citations
13*
Sensitivity study of Protvino to ORCA (P2O) experiment: Effect of antineutrino run, background and systematics
Sandhya Choubey🇮🇳 · Monojit Ghosh🇮🇳 · Dipyaman Pramanik🇮🇳
There is a proposal to send a neutrino beam from the Protvino accelerator complex located in Russia to the detector facility called `Oscillation Research with Cosmics in the Abyss' (ORCA) in the Mediterranean sea to study neutrino oscillation. This is called the P2O experiment which will have a baseline of 2588 km. In this paper, we carry out a sensitivity study to extract the best possible physics sensitivity of the P2O experiment. In particular, we study the effect of antineutrino runs, the role of background as well as the impact of controlling the systematic uncertainties vis-a-vis the statistics.
hep-phEPJC(2019)·8 citations
14*
Systematic construction of basis invariants in the 2HDM
Andreas Trautner🇩🇪
A new systematic method for the explicit construction of (basis-)invariants is introduced and employed to construct the full ring of basis invariants of the Two-Higgs-Doublet-Model (2HDM) scalar sector. Co- and invariant quantities are obtained by the use of hermitian projection operators. These projection operators are constructed from Young tableaux via birdtrack diagrams and they are used in two steps. First, to extract basis-covariant quantities, and second, to combine the covariants in order to obtain the actual basis invariants. The Hilbert series and Plethystic logarithm are used to find the number and structure of the complete set of generating invariants as well as their interrelations (syzygies). Having full control over the complete ring of (CP-even and CP-odd) basis invariants, we give a new and simple proof of the necessary and sufficient conditions for explicit CP conservation in the 2HDM, confirming earlier results by Gunion and Haber. The method generalizes to other models, with the only foreseeable limitation being computing power.
hep-phhep-thJHEP(2019)·40 citations
15*
Bounds on lepton flavor violating physics and decays of neutral mesons from $τ (μ) \to 3 ℓ, ℓ γ γ$ -decays
Claudio O. Dib🇨🇱 · Thomas Gutsche🇩🇪 · Sergey G. Kovalenko🇨🇱 · Valery E. Lyubovitskij🇩🇪 · Ivan Schmidt🇨🇱
We study two- and three-body lepton flavor violating (LFV) decays involving leptons and neutral vector bosons $V = ρ^{0}, ω, ϕ, J / ψ, Υ, Z^{0}$ , as well as pseudo-scalar $P = π^{0}, η, η^{'}, η_{c}$ and scalar $S = f_{0} (500), f_{0} (980), a_{0} (980), χ_{c 0} (1 P)$ mesons, without referring to a specific mechanism of LFV realization. In particular, we relate the rates of the three-body LFV decays $τ (μ) \to 3 ℓ$ , where $ℓ = μ$ or $e$ , to the two-body LFV decays $(V, P) \to τ μ (τ e, μ e)$ , where $V$ and $P$ play the role of intermediate resonances in the decay process $τ (μ) \to 3 ℓ$ . From the experimental upper bounds for the branching ratios of $τ (μ) \to 3 ℓ$ decays, we derive upper limits for the branching ratios of $(V, P) \to τ μ (τ e, μ e)$ . We compare our results to the available experimental data and known theoretical upper limits from previous studies of LFV processes, and find that some of our limits are several orders of magnitude more stringent. Using the idea of quark-hadron duality, we extract limits on various quark-lepton dimension-six LFV operators from data on lepton decays. Some of these limits are either new or stronger than those existing in the literature.
hep-phPRD(2019)·13 citations
16*
Why is there more matter than antimatter? Calculational methods for leptogenesis and electroweak baryogenesis
Bjorn Garbrecht🇩🇪
We review the production of the matter-antimatter asymmetry in the early Universe, that is baryogenesis, in out-of-equlibrium conditions induced by decays of heavy particles or by the presence of phase boundaries. The most prominent examples are given by leptogenesis and electroweak baryogenesis, respectively. For both cases, we derive the equations that govern the production of the asymmetries. We first use intuitive arguments based on classical fluid equations in combination with quantum-field-theoretical effects of CP-violation. As for a more thorough approach that is well-suited for systematic improvements, we obtain the real-time evolution of the system of interest using the closed time-path method. We thus provide a simple and practicable scheme to set up phenomenological fluid equations based on first principles of quantum field theory. Necessary for baryogenesis are both, CP even as well as odd phases in the amplitudes. A possibility of generating the even phases is the coherent superposition of quantum states, i.e. mixing. These coherence effects are essential in resonant leptogenesis as well as in some scenarios of electroweak baryogenesis. Recent theoretical progress on asymmetries from out-of-equlibrium decays may therefore also be applicable to baryogenesis at phase boundaries.
hep-phPPNP(2020)·103 citations
17*
TASI Lectures on the Strong CP Problem and Axions
Anson Hook🇺🇸
These TASI lectures where given in 2018 and provide an introduction to the Strong CP problem and the axion. I start by introducing the Strong CP problem from both a classical and a quantum mechanical perspective, calculating the neutron eDM and discussing the $θ$ vacua. Next, I review the various solutions and discuss the active areas of axion model building. Finally, I summarize various experiments proposed to look for these solutions.
hep-phPoS(2019)·261 citations
18*
Probing New Physics in $B \to π K$ Decays
Robert Fleischer🇳🇱 · Ruben Jaarsma🇳🇱 · Eleftheria Malami🇳🇱 · K. Keri Vos🇩🇪
Over the last two decades, $B \to π K$ modes have received a lot of attention. They are particularly interesting since the main contribution to these decays comes from QCD penguin topologies. Furthermore, electroweak penguin amplitudes enter at a level comparable to the tree topologies. In the past, a discrepancy was found in the correlation between the CP asymmetries of $B_{d}^{0} \to π^{0} K_{S}$ . We provide the state-of-the-art picture of this situation and consider new constraints, finding that the effect has become larger. An attractive explanation is offered by a modified electroweak penguin sector. We propose a new method to determine the relevant parameters. It employs an isospin relation between the amplitudes of the $B \to π K$ decays, and makes only minimal use of the $S U (3)$ flavour symmetry. Using current data as well as future scenarios, we demonstrate how the mixing-induced CP asymmetry of $B_{d}^{0} \to π^{0} K_{S}$ plays a key role in this analysis. The application of our strategy at the next generation of $B$ -physics experiments may establish New Physics and reveal new sources of CP violation in the electroweak penguin sector.
hep-phhep-exPoS(2018)·3 citations
19*
Probing New Physics by the Tail of the Off-shell Higgs in $V_{L} V_{L}$ Mode
Seung J. Lee🇰🇷 · Myeonghun Park🇰🇷 · Zhuoni Qian🇰🇷
Off-shell Higgs at the high mass tail may shed light on the underlying mechanism of the electroweak symmetry breaking. Due to the large cancellation in the standard model (SM) between the box and Higgs-mediated triangle diagrams, the $g g \to W W (Z Z)$ process in the SM is dominated by the $V_{T} V_{T}$ transverse-mode at the high mass tail. The cancellation does not necessarily hold, when there is a sufficiently large new physics contribution resulting in $V_{L} V_{L}$ longitudinal mode, which is commonly the case when the Higgs sector is modified. Thus the $V_{L} V_{L}$ final states in the high mass tail can be utilized as a sensitive probe for such models. In the paper we focus on a study of the $g g \to Z Z$ process in the fully leptonic decay modes, proposing to utilize the polarization modes of the off-shell Higgs to probe new physics, whose contribution mainly shows in the longitudinal mode. As examples, we analyze three different Higgs sector new physics cases (Higgs portal with a light scalar, a broad-width scalar that mixes with the Higgs, and quantum critical Higgs models), and demonstrate that the angular information relating to the polarization serves as very sensitive probe for such new physics.
hep-phPRD(2019)·15 citations
20*
Baryon-antiBaryon Charge Asymmetry at LHC: String Junction Transfer and SJ Torus as DM Candidate
Olga I. Piskounova🇷🇺
The asymmetry of baryon/antibaryon production has been measured in many proton-proton, pion-proton and electron-proton experiments. In the framework of Quark-Gluon String Model (QGSM) the energy dependence of asymmetry tells us about the value of $α_{S J}$ (0), the intercept of String Junction Regge trajectory. In previous QGSM study, the value of intercept has been estimated as 0.5 < $α_{S J}$ (0) < 0.9. Here, SJ behaviors are accumulated in the model based on topological expansion in order to build a neutral object with zero baryon charge. By the way, QCD mass falling under the event horizon of Black Hole (BH) should be symmetric, or in other words, have no charge information. The baryon junctions are easily combinable with antibaryon ones in hexagons. Topologically, hexagon net can coherently cover only the torus surface. The net on the torus has discrete number of baryon/antibaryon junctions. This is only parameter that marks the mass/energy level of this object. It looks like DM particle, is not it? In high energy collisions at LHC, such pomeron loops are to be produced approximately in 1.2 percent of inelastic events. Furthermore, the torus configurations of matter have been revealed in many bright events in space. As an example, Chandra experiment has detected such dense "doughnut" near the event horizon of Super Massive Black Hole (SMBH), which X-ray radiation is screened on 40 percent's. This topological symmetry model of DM seems rather realistic and can help us to deal with an "arm wrestling" between the stiffness of toroid structure of QCD matter and the pressure of gravitational singularity at extremely heavy masses. On the other hand, the instabilities in structure of matter in SMBHs can cause the bursts of giant relativistic hadron jets with the masses of order the own BH mass.
hep-ph7 citations
21*
A Numerical Routine for the Crossed Vertex Diagram with a Massive-Particle Loop
Roberto Bonciani🇮🇹 · Giuseppe Degrassi🇮🇹 · Pier Paolo Giardino🇪🇸 · Ramona Gröber🇬🇧
We present an evaluation of the two master integrals for the crossed vertex diagram with a closed loop of top quarks that allows for an easy numerical implementation. The differential equations obeyed by the master integrals are used to generate power series expansions centered around all the singular points. The different series are then matched numerically with high accuracy in intermediate points. The expansions allow a fast and precise numerical calculation of the two master integrals in all the regions of the phase space. A numerical routine that implements these expansions is presented.
hep-phComput.Phys.Commun.(2019)·35 citations
22*
PROSA PDFs and astrophysical applications
Maria Vittoria Garzelli (for the PROSA collaboration)🇩🇪
The PROSA parton distribution function fit was the first one appeared in the literature incorporating data on open charm and open bottom production at LHCb, in order to reduce the uncertainties on gluons and sea quarks at low $x$ 's ( $x$ $<$ $1 0^{- 4}$ ). We discuss aspects of the PROSA PDFs of particular relevance for their usage in the field of Neutrino Astronomy, and their application in the computation of prompt neutrino fluxes.
hep-phActa Phys.Polon.Supp.(2019)·1 citation
23*
Light hidden photon production in high energy collisions
S. Demidov🇷🇺 · S. Gninenko🇷🇺 · D. Gorbunov🇷🇺
The visible and dark sectors of particle physics can be connected via kinetic mixing between ordinary and hidden photons. If the latter is light its production in high energy collisions of ordinary particles proceeds via oscillations with ordinary photons similarly to the neutrino processes. Generically, the experiments are insensitive to mass of the hidden vector, if it is lighter than 1\,MeV, and it does not decay into $e^{+} e^{-}$ -pair. Still, one can use the missing energy and scattering off the detector material as signatures to search for the light vectors. Presence of media suppresses production of the light vectors making the experiments insensitive to the entire model. We present analytic formulas for the light hidden photon production, propagation and detection valid for searches at colliders and beam-target experiments and apply them to estimate the impact on the sensitivities of a set of experiments --- NA64, FASER, MATHUSLA, SHiP, T2K, DUNE, NA62 --- in a zero-background case.
hep-phhep-exJHEP(2019)·15 citations
24*
Possible Bilepton Resonances in Like-Sign Pairs
Claudio Coriano🇮🇹 · Paul H. Frampton🇮🇹
We consider pair production of bileptons $Y^{++} Y^{--}$ at the LHC for the presently accumulated integrated luminosity of $150/ f m$ . It is shown that the entire mass range 800 GeV $\leq$ M(Y) $\leq$ 2000 GeV can be successfully searched. A bilepton resonance will have an exceptionally large ratio of signal to background because the standard model prediction is so infinitesimal. A $5 σ$ discovery is quite feasible.
hep-phMod.Phys.Lett.A(2019)·8 citations
25*
Partial compositeness and baryon matrix elements on the lattice
Venkitesh Ayyar🇺🇸 · Thomas DeGrand🇺🇸 · Daniel C. Hackett🇺🇸 · William I. Jay🇺🇸 · Ethan T. Neil🇺🇸 · Yigal Shamir🇮🇱 · Benjamin Svetitsky🇮🇱
Partial compositeness is a mechanism for the generation of fermion masses which replaces a direct Higgs coupling to the fermions by a linear mixing with heavy composite partners. We present the first calculation of the relevant matrix element in a lattice model which is very close to a candidate theory containing a composite Higgs boson and a partially composite top quark. Specifically, our model is an SU(4) gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations. The matrix element we obtain is small and hence our result disfavors the scenario of obtaining a realistic top mass in this model.
hep-phhep-latPRD(2019)·67 citations
26*
Gauge invariance for a class of tree diagrams in the standard model
Tai Tsun Wu🇺🇸 · Sau Lan Wu🇺🇸
For gauge theory, the matrix element for any physical process is independent of the gauge used. Since this is a formal statement and examples are known where gauge invariance is violated, for any specific process this gauge invariance needs to be checked by explicit calculation. In this paper, gauge invariance is found to hold for a large non-trivial class of processes described by tree diagrams in the standard model -- tree diagrams with two external $W$ bosons and any number of external Higgs bosons. This verification of gauge invariance is quite complicated, and is based on a direct study of the difference between different gauges through induction on the number of external Higgs bosons.
hep-phhep-th0 citations
27*
Gravitational Waves from a Pati-Salam Phase Transition
Djuna Croon🇨🇦 · Tomás E. Gonzalo🇳🇴 · Graham White🇨🇦
We analyse the gravitational wave and low energy signatures of a Pati-Salam phase transition. For a Pati-Salam scale of $M_{P S} \sim 1 0^{5}$ GeV, we find a stochastic power spectrum within reach of the next generation of ground-based interferometer experiments such as the Einstein Telescope, in parts of the parameter space. We study the lifetime of the proton in this model, as well as complementarity with low energy constraints including electroweak precision data, neutrino mass measurements, lepton flavour violation, and collider constraints.
hep-phastro-ph.COJHEP(2019)·77 citations
28*
A General Classification of Starobinsky-like Inflationary Avatars of SU(2,1)/SU(2) x U(1) No-Scale Supergravity
John Ellis🇬🇧 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸 · Sarunas Verner🇺🇸
Measurements of the cosmic microwave background (CMB) favour models of inflation with a small tensor-to-scalar ratio r, as predicted by the Starobinsky R + R^2 model. It has been shown previously that various models based on no-scale supergravity with different forms of superpotential make predictions similar to those of the Starobinsky model. In this paper we present a unified and general treatment of Starobinsky avatars of no-scale supergravity, using the underlying non-compact SU(2,1)/SU(2) x U(1) symmetry to demonstrate equivalences between different models, exhibiting 6 specific equivalence classes.
↳ hep-thastro-ph.COhep-phJHEP(2019)·53 citations
29*
Transverse Takahashi Identities and Their Implications for Gauge Independent Dynamical Chiral Symmetry Breaking
L. Albino🇲🇽 · A. Bashir🇲🇽 · L.X. Gutiérrez Guerrero🇲🇽 · B. El Bennich🇧🇷 · E. Rojas🇨🇴
In this article, we employ transverse Takahashi identities to impose valuable non-perturbative constraints on the transverse part of the fermion-photon vertex in terms of new form factors, the so called $Y_{i}$ functions. We show that the implementation of these identities is crucial in ensuring the correct local gauge transformation of the fermion propagator and its multiplicative renormalizability. Our construction incorporates the correct symmetry properties of the $Y_{i}$ under charge conjugation operation as well as their well-known one-loop expansion in the asymptotic configuration of incoming and outgoing momenta. Furthermore, we make an explicit analysis of various existing constructions of this vertex against the demands of transverse Takahashi identities and the previously established key features of quantum electrodynamics, such as gauge invariance of the critical coupling above which chiral symmetry is dynamically broken. We construct a simple example in its quenched version and compute the mass function as we vary the coupling strength and also calculate the corresponding anomalous dimensions $γ_{m}$ . There is an excellent fit to the Miransky scalling law and we find $γ_{m} = 1$ rather naturally in accordance with some earlier results in literature, using arguments based on Cornwall-Jackiw-Tomboulis effective potential technique. Moreover, we numerically confirm the gauge invariance of this critical coupling.
↳ nucl-thhep-phPRD(2019)·48 citations
30*
Supersymmetric gradient flow in N=1 SYM
Daisuke Kadoh🇹🇭 · Naoya Ukita🇯🇵
The gradient flow equation is derived in four-dimensional N=1 supersymmetric Yang-Mills theory in terms of the component field of the Wess-Zumino gauge. We show that the flow-time derivative and supersymmetry transformation that is naively extended to 4+1 dimensions by replacing the four-dimensional fields with the corresponding flowed fields commute with each other up to a gauge transformation. In this sense, the obtained flow is supersymmetric in the Wess-Zumino gauge. We also discuss more about the symmetry of the flow equation.
↳ hep-thhep-lathep-phmath-ph+1EPJC(2022)·10 citations
31*
F-term Moduli Stabilization and Uplifting
Tatsuo Kobayashi🇯🇵 · Osamu Seto🇯🇵 · Shintaro Takada🇯🇵 · Takuya H. Tatsuishi🇯🇵 · Shohei Uemura🇯🇵 · Junji Yamamoto🇯🇵
We study Kähler moduli stabilization in IIB superstring theory. We propose a new moduli stabilization mechanism by the supersymmetry-braking chiral superfield which is coupled to Kähler moduli in Kähler potential. We also study uplifting of the Large Volume Scenario (LVS) by it. In both cases, the form of superpotential is crucial for moduli stabilization. We confirm that our uplifting mechanism does not destabilize the vacuum of the LVS drastically.
↳ hep-thhep-phPTEP(2019)·1 citation
32*
Precise measurements of CP violation in B decays at Belle II
Benjamin Oberhof🇮🇹
We report expected sensitivities for the measurement of the three angles of the Unitarity Triangle in B meson decays using 50 ab-1 of electron-positron collisions recorded by the Belle II detector at the SuperKEKB collider at KEK, Japan.
↳ hep-exhep-phPoS(2018)·0 citations
33*
Parton energy loss effect on Z+jet production in high-energy nuclear collisions
Shan-Liang Zhang🇨🇳 · Tan Luo🇨🇳 · Xin-Nian Wang🇨🇳 · Ben-Wei Zhang🇨🇳
We give a report of medium modification of Z+jet correlations in Pb+Pb collisions at the Large Hadron Collider using Sherpa to generate initial Z+jet at next-leading-order matrix element matched parton shower, and the Linear Boltzmann Transport Model for jet propagation in the expanding quark-gluon-plasma. Our numerical calculations show excellent agreement with all available observables of Z+jet simultaneously in both proton + proton and Pb+Pb collisions. Our results can well explain the shift of momentum asymmetry $x_{j Z} = p_{T}^{j e t} / p_{T}^{Z}$ as well as its mean values, the suppression of the jet yields per Z trigger $R_{j Z}$ and the modification of azimuthal angle correlation $Δ ϕ_{j Z}$ . We also demonstrate that it is the energy loss effect on multi-jets from high-order corrections that leads to the suppression of the Z+jet correlation at small azimuthal angle difference $Δ ϕ_{j Z}$ and at small $x_{j Z}$ . The jet shape reflecting transverse momentum distribution inside the jet is also calculated, which indicates that large fraction of jet energy is carried away from the jet axis in Pb+Pb collisions.
↳ nucl-thhep-phPoS(2018)·0 citations
34*
Non-Canonical Inflation and Primordial Black Holes Production
Alexander Y. Kamenshchik🇮🇹 · Alessandro Tronconi🇮🇹 · Tereza Vardanyan🇮🇹 · Giovanni Venturi🇮🇹
We study a mechanism for the amplification of the inflationary scalar perturbation when the inflaton field action is non-canonical, i.e. the inflaton kinetic term has a non-standard form. For such a case the speed of sound of the perturbations generated during inflation is less than one and in general changes with time. Furthermore in such models, even when the scalar field potential is negligible, diverse inflationary attractors may exist. The possible effects of a speed of sound approaching zero during some stage of inflation may lead to a large amplification for the amplitude of the scalar spectrum which, on horizon re-entry during the radiation dominated phase, can collapse and form primordial black holes (PBH) of a mass $M_{BH} \sim 1 0^{- 15} M_{⊙}$ which may constitute a large fraction of the total Dark Matter (DM) today.
↳ gr-qcastro-ph.COhep-phhep-thPLB(2019)·84 citations
35*
Defining the Proton Radius: a Unified Treatment
Gerald A. Miller🇺🇸
Background: There is significant current interest in knowing the value of the proton radius and also its proper definition. Purpose: Combine the disparate literatures of hydrogen spectroscopy and diverse modern parton distributions to show that the quantity $r_{p}^{2} \equiv - 6 G_{E}^{'} (0)$ is the relativistically proper definition that originates from the separate bodies of work. Methods: Use perturbation theory, light-front dynamics and elementary techniques to find relativistically correct definitions of the proton radius and charge density. Results: It is found that the very same proton radius is accessed by measurements of hydrogen spectroscopy and elastic lepton scattering. The derivation of the mean-square radius as a moment of a spherically symmetric three-dimensional density is shown to be incorrect. A relativistically-correct, two-dimensional charge density is related to the diverse modern literature of various parton distributions. Relativistically invariant moments thereof are derived in a new moment expansion, the RME.
↳ nucl-thhep-phnucl-exphysics.atom-phPRC(2019)·138 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.