Wed·Sep 26, 2018Wednesday·September 26, 2018

1. 01*

   Normal-mode Analysis for Collective Neutrino Oscillations

   Sagar Airen (MPP Munich, IIT Bombay)🇮🇳 · Francesco Capozzi (MPP Munich)🇩🇪 · Sovan Chakraborty (MPP Munich, IIT Guwahati)🇮🇳 · Basudeb Dasgupta (TIFR Mumbai)🇮🇳 · Georg Raffelt (MPP Munich)🇩🇪 · Tobias Stirner (MPP Munich)🇩🇪

   In an interacting neutrino gas, collective modes of flavor coherence emerge that can be propagating or unstable. We derive the general dispersion relation in the linear regime that depends on the neutrino energy and angle distribution. The essential scales are the vacuum oscillation frequency $\omega =\Delta m^2/(2E)$, the neutrino-neutrino interaction energy $\mu =\sqrt{2}{G}_{\mathrm{F}}{n}_{\nu }$, and the matter potential $\lambda =\sqrt{2}{G}_{\mathrm{F}}{n}_e$. Collective modes require non-vanishing $\mu$ and may be dynamical even for $\omega =0$ ('fast modes'), or they may require $\omega \ne 0$ ('slow modes'). The growth rate of unstable fast modes can be fast itself (independent of $\omega$) or can be slow (suppressed by $\sqrt{|\omega /\mu |}$). We clarify the role of flavor mixing, which is ignored for the identification of collective modes, but necessary to trigger collective flavor motion. A large matter effect is needed to provide an approximate fixed point of flavor evolution, while spatial or temporal variations of matter and/or neutrinos are required as a trigger, i.e., to translate the disturbance provided by the mass term to seed stable or unstable flavor waves. We work out explicit examples to illustrate these points.

   hep-phastro-ph.SRJCAP(2018)·75 citations
2. 02*

   Sigma-assisted natural composite Higgs

   Diogo Buarque Franzosi🇸🇪 · Giacomo Cacciapaglia🇫🇷 · Aldo Deandrea🇫🇷

   We show that the presence of a lightish scalar resonance, $\sigma$, that mixes with the composite Goldstone-Higgs boson can relax the typical bounds found in this class of models. This mechanism, inbred in models with a walking dynamics above the condensation scale, allows for a low compositeness scale $f\gtrsim 400$ GeV, corresponding to a misalignment angle $\sin \theta \lesssim 0.6$, contrary to the common lore of a smaller angle. According to recent lattice results, the light $\sigma$ emerges thanks to a near-conformal phase above the condensation scale, consistent to the requirements from flavour physics. We study this effect in a general way, showing that it appears in all cosets emerging from an underlying gauge-fermion dynamics, in the presence of top partial compositeness. The scenario is testable both on the Lattice and experimentally, as it requires the presence of a second broad Higgs-like resonance, below 1 TeV, that can be revealed at the LHC in the $ZZ$ and $t\bar{t}$ channels.

   hep-phEPJC(2020)·45 citations
3. 03*

   Dark Matter in the Standard Model Extension with Singlet Quark

   Vitaliy Beylin🇷🇺 · Vladimir Kuksa🇷🇺

   We analyze the possibility of hadron Dark Matter carriers consisting of singlet quark and the light standard one. It is shown that stable singlet quarks generate effects of new physics which do not contradict to restrictions from precision electroweak data. The neutral and charged pseudoscalar low-lying states are interpreted as the Dark Matter particle and its mass-degenerated partner. We evaluated their masses and lifetime of the charged component, and describe asymptotics of the potential of low-energy interactions of these particles with nucleons and with each other. Some peculiarities of Sommerfeld enhancement effect in the annihilation process are also discussed.

   hep-phAdv.High Energy Phys.(2018)·8 citations
4. 04*

   Impact of Matter Density Profile Shape on Non-Standard Interactions at DUNE

   Animesh Chatterjee🇺🇸 · Felipe Kamiya🇧🇷 · Celio A. Moura🇧🇷 · Jaehoon Yu🇺🇸

   We discuss the impact of matter density profile shape on the determination of nonstandard neutrino matter interactions (NSI) in the context of the long baseline accelerator experiments such as Deep Underground Neutrino Experiment (DUNE). The primary scientific goals of DUNE are to determine the neutrino mass hierarchy, the leptonic CP violation phase, and the existence of new physics beyond the standard model of particles. Here we study the role of different earth matter density profiles on the question of observing standard oscillation as wells as NSI at DUNE. We consider two different earth matter density profiles which are relevant for the DUNE baseline. We first discuss the impact of matter on both appearance and disappearance oscillation channels, then we demonstrate the effect of different matter density profiles on the determination of NSI. We consider four different scenarios of NSI and elucidate the effect at the oscillation probability and measurement of number of events at DUNE. In one case of study we show that a nonstandard complex phase ${\varphi }_{e\tau }$ could significantly increase the sensitivity to different matter distributions along the baseline.

   hep-ph13 citations
5. 05*

   Independently Parameterised Momenta Variables and Monte Carlo IR Subtraction

   Peter Cox🇯🇵 · Tom Melia🇯🇵

   We introduce a system of parameters for the Monte Carlo generation of Lorentz invariant phase space that is particularly well-suited to the treatment of the infrared divergences that occur in the most singular, Born-like configurations of $1\to n$ QCD processes. A key feature is that particle momenta are generated independently of one another, leading to a simple parameterisation of all such IR limits. We exemplify the use of these variables in conjunction with the projection to Born subtraction technique at next-to-next-to-leading order. The geometric origins of this parameterisation lie in a coordinate chart on a Grassmannian manifold.

   hep-phJHEP(2018)·11 citations
6. 06*

   Higher moments on strangeness fluctuation using PNJL model

   Paramita Deb🇮🇳 · Amal Sarkar🇿🇦 · Raghava Varma🇮🇳

   The strangeness fluctuation of QGP matter has been investigated in three flavor finite volume Polyakov loop extended Nambu-Jona--Lasinio model. The ratio of fourth order moment to second order moment (kurtosis) and the third order moment to second order moment (skewness) of strangeness fuctuations have been studied and compared with the experimental data. The cross correlations related to baryon number, strangeness and electric charge conservation have also been discussed. Skewness and kurtosis of strangeness fluctuation in PNJL model have similar features along the collision energy of heavy ion experiments.

   hep-ph0 citations
7. 07*

   FCNC decays of the Higgs bosons in the BGL model

   Alexander Bednyakov🇷🇺 · Veronika Rutberg🇷🇺

   We consider flavor-changing decays of neutral Higgs bosons in the context of CP-conserving BGL model - a variant of 2HDM Type 3 model suggested by Branco, Grimus and Lavoura - in which tree-level FCNC couplings are suppressed by elements of known fermion mixing matrices. The relevant regions of parameter space compatible with experimental restrictions on the SM Higgs properties are studied. We also include current bounds on h-> mu tau into consideration. In addition, different FCNC decay modes are analyzed for heavier Higgs states (H/A) and conservative estimates for Br(A/H->mu tau) are provided. We updated previous studies and found that it can not be more than 30% for heavy Higgses with masses around 350 GeV.

   hep-phMod.Phys.Lett.A(2018)·6 citations
8. 08*

   Majorons as cold light dark matter

   Julian Heeck🇧🇪

   Majorons are the Goldstone bosons of spontaneously broken lepton number and hence intimately connected to Majorana neutrino masses. Since all majoron couplings are heavily suppressed by the seesaw scale they are interesting candidates for long-lived dark matter. The signature decay into two mono-energetic neutrinos is potentially detectable with neutrino detectors for majoron masses above MeV and complementary to the loop-induced decays into visible particles. The mass range between keV and MeV can only be probed indirectly with the majoron decay into two photons; keV-scale majorons can be warm or cold dark matter depending on the underlying freeze-in mechanism.

   hep-phPoS(2018)·4 citations
9. 09*

   The improved Ginzburg-Landau technique

   Massimo Mannarelli🇮🇹

   We discuss an innovative method for the description of inhomogeneous phases designed to improve the standard Ginzburg-Landau expansion. The method is characterized by two key ingredients. The first one is a moving average of the order parameter designed to account for the long-wavelength modulations of the condensate. The second one is a sum of the high frequency modes, to improve the description of the phase transition to the restored phase. The method is applied to compare the free energies of 1D and 2D inhomogeneous structures arising in the chirally symmetric broken phase.

   hep-phEPJ Web Conf.(2018)·0 citations
10. 10*

    Theory of Mixing and CP violation

    Alexander Lenz🇬🇧

    We review the current status of B-mixing observables and point out the crucial importance of a control of the hadronic uncertainties for ruling out or confirming hints of BSM physics. In addition we introduce a rating system for theory predictions for lifetimes and mixing observables, that classifies the quality of the corresponding SM values ranging from no star to ****

    hep-phhep-exhep-latPoS(2018)·3 citations
11. 11*

    Role of transverse momentum dependence of unpolarised parton distribution and fragmentation functions in the analysis of azimuthal spin asymmetries

    M. Anselmino🇮🇹 · M. Boglione🇮🇹 · U. D'Alesio🇮🇹 · F. Murgia🇮🇹 · A. Prokudin🇺🇸

    Information on the Sivers distribution and the Collins fragmentation functions and their transverse momentum dependence is mainly based on fitting single spin asymmetry data from semi-inclusive deep inelastic scattering (SIDIS). Independent information, respectively on the Sivers distribution and the Collins fragmentation, can be obtained from Drell-Yan and $e^{+}{e}^{-}$ annihilation processes. In the SIDIS case, the transverse momentum of the final observed hadron, which is the quantity measured, is generated both by the average transverse momentum in the distribution and in the fragmentation functions. As a consequence, these are strongly correlated and a separate extraction is made difficult. In this paper we investigate, in a simple kinematical Gaussian configuration, this correlation, its role on the transverse single spin asymmetries in SIDIS and the consequences for predictions of the Sivers asymmetry in Drell-Yan processes and for the Collins asymmetry in $e^{+}{e}^{-}$ annihilation. We find that, in some cases, these effects can be relevant and must be carefully taken into account.

    hep-phPRD(2018)·14 citations
12. 12*

    Optimising the ILC Setup: Physics Programme, Running Scenarios and Design Choices

    Jenny List🇩🇪 · Gudrid Moortgat-Pick🇩🇪 · Jürgen Reuter🇩🇪

    A high-energy $e^{+}{e}^{-}$ Linear Collider has been considered since a long time as an important complement to the LHC. Unprecedented precision measurements as well as the exploration of so far untouched phase space for direct production of new particles will provide unique information to advance the limits of our understanding of our universe. Within this project, the physics prospects of such a collider as well as their interplay with design of the accelerator and the detectors have been investigated in a quantitative way. This kind of study required a close collaboration between theory and experiment, always taking into account results of the LHC and other relevant experiments. In this article we will summarize some of the most important developments and results, covering all core areas of the physics progamme of future $e^{+}{e}^{-}$ colliders.

    hep-phhep-ex2 citations
13. 13*

    Constraining high-energy neutrinos from choked-jet supernovae with IceCube high-energy starting events

    Arman Esmaili🇧🇷 · Kohta Murase🇺🇸

    Different types of core-collapse supernovae (SNe) have been considered as candidate sources of high-energy cosmic neutrinos. Stripped-envelope SNe, including energetic events like hypernovae and super-luminous SNe, are of particular interest. They may harbor relativistic jets, which are capable of explaining the diversity among gamma-ray bursts (GRBs), low-luminosity GRBs, ultra-long GRBs, and broadline Type Ib/c SNe. Using the six-year IceCube data on high-energy starting events (HESEs), we perform an unbinned maximum likelihood analysis to search for spatial and temporal coincidences with 222 samples of SNe Ib/c. We find that the present data are consistent with the background only hypothesis, by which we place new upper constraints on the isotropic-equivalent energy of cosmic rays, ${\mathcal{E}}_{\mathrm{cr}}\lesssim {10}^{52}\mathrm{erg}$, in the limit that all SNe are accompanied by on-axis jets. Our results demonstrate that not only upgoing muon neutrinos but also HESE data enable us to constrain the potential contribution of these SNe to the diffuse neutrino flux observed in IceCube. We also discuss implications for the next-generation neutrino detectors such as IceCube-Gen2.

    hep-phastro-ph.COastro-ph.HEJCAP(2018)·38 citations
14. 14*

    Constraining four-fermion operators using rare top decays

    Mikael Chala🇬🇧 · Jose Santiago🇪🇸 · Michael Spannowsky🇬🇧

    New physics can manifest itself by an appreciable increase of the decay rate of top quarks in rare flavour-changing final states. Exploiting the large top quark production rate at the LHC, we bound four-fermion operators contributing to non-resonant $t\to {\ell }^{+}{\ell }^{-}j$ using different signal regions of the latest LHC searches for $t\to Zj$. We also provide prospects for the high-luminosity LHC to test these as well as four-fermion operators contributing to $t\to b\overline{b}j$, based on improved analysis strategies of existing searches. We single out all weakly-coupled ultraviolet completions inducing such contact interactions at tree level and translate the previous bounds to the parameter space of specific complete models. Being above the TeV, LHC bounds from rare top decays improve over those from flavour physics, electroweak precision data and other LHC searches in several cases.

    hep-phJHEP(2019)·67 citations
15. 15*

    The interacting multiverse and its effect on the cosmic microwave background

    Mariam Bouhmadi-López🇪🇸 · Manuel Kraemer🇵🇱 · João Morais🇪🇸 · Salvador Robles-Pérez🇪🇸

    We study a toy model of a multiverse consisting of canonically quantized universes that interact with each other on a quantum level based on a field-theoretical formulation of the Wheeler-DeWitt equation. This interaction leads to the appearance of a pre-inflationary phase in the evolution of the individual universes. We analyze scalar perturbations within the model and calculate the influence of the pre-inflationary phase onto the power spectrum of these perturbations. The result is that there is a suppression of power on large scales, which can describe well the Planck 2018 data for the cosmic microwave background anisotropies and could thus indicate a possible solution to the observed quadrupole discrepancy.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2019)·14 citations
16. 16*

    Early galaxy formation and its large-scale effects

    Pratika Dayal🇳🇱 · Andrea Ferrara🇮🇹

    Galaxy formation is at the heart of our understanding of cosmic evolution. Although there is a consensus that galaxies emerged from the expanding matter background by gravitational instability of primordial fluctuations, a number of additional physical processes must be understood and implemented in theoretical models before these can be reliably used to interpret observations. In parallel, the astonishing recent progresses made in detecting galaxies that formed only a few hundreds of million years after the Big Bang is pushing the quest for more sophisticated and detailed studies of early structures. In this review, we combine the information gleaned from different theoretical models/studies to build a coherent picture of the Universe in its early stages which includes the physics of galaxy formation along with the impact that early structures had on large-scale processes as cosmic reionization and metal enrichment of the intergalactic medium.

    ↳ astro-ph.GAhep-phPhys.Rept.(2018)·193 citations
17. 17*

    Weyl gauge symmetry and its spontaneous breaking in Standard Model and inflation

    D. M. Ghilencea🇷🇴 · Hyun Min Lee🇰🇷

    We discuss the local (gauged) Weyl symmetry and its spontaneous breaking and apply it to model building beyond the Standard Model (SM) and inflation. In models with non-minimal couplings of the scalar fields to the Ricci scalar, that are conformal invariant, the spontaneous generation by a scalar field(s) vev of a positive Newton constant demands a negative kinetic term for the scalar field, or vice-versa. This is naturally avoided in models with additional Weyl gauge symmetry. The Weyl gauge field ${\omega }_{\mu }$ couples to the scalar sector but not to the fermionic sector of a SM-like Lagrangian. The field ${\omega }_{\mu }$ undergoes a Stueckelberg mechanism and becomes massive after "eating" the (radial mode) would-be-Goldstone field (dilaton $\rho$) in the scalar sector. Before the decoupling of ${\omega }_{\mu }$, the dilaton can act as UV regulator and maintain the Weyl symmetry at the {\it quantum} level, with relevance for solving the hierarchy problem. After the decoupling of ${\omega }_{\mu }$, the scalar potential depends only on the remaining (angular variables) scalar fields, that can be the Higgs field, inflaton, etc. We show that successful inflation is then possible with one of these scalar fields identified as the inflaton. While our approach is derived in the Riemannian geometry with ${\omega }_{\mu }$ introduced to avoid ghosts, the natural framework is that of Weyl geometry which for the same matter spectrum is shown to generate the same Lagrangian, up to a total derivative.

    ↳ hep-thgr-qchep-phPRD(2019)·90 citations
18. 18*

    A New Method for Reducing PDF Uncertainties in the High-Mass Drell-Yan Spectrum

    Christopher Willis🇺🇸 · Raymond Brock🇺🇸 · Daniel Hayden🇺🇸 · Tie-Jiun Hou🇺🇸 · Joshua Isaacson🇺🇸 · Carl Schmidt🇺🇸 · Chien-Peng Yuan🇺🇸

    Uncertainties in the parametrization of Parton Distribution Functions (PDFs) are becoming a serious limiting systematic uncertainty in Large Hadron Collider (LHC) searches for Beyond the Standard Model physics. This is especially true for measurements at high scales induced by quark and anti-quark collisions, where Drell-Yan continuum backgrounds are dominant. Tools are recently available which enable exploration of PDF fitting strategies and emulate the effects of new data in a future global fit. ePump is such a tool and it is shown that judicious selection of measurable kinematical quantities can reduce the assigned systematic PDF uncertainties by significant factors. This will be made possible by the huge statistical precision of future LHC Standard Model datasets.

    ↳ hep-exhep-phPRD(2019)·23 citations
19. 19*

    The ANITA Anomalous Events as Signatures of a Beyond Standard Model Particle, and Supporting Observations from IceCube

    Derek B. Fox🇺🇸 · Steinn Sigurdsson🇺🇸 · Sarah Shandera🇺🇸 · Peter Mészáros🇺🇸 · Kohta Murase🇺🇸 · Miguel Mostafá🇺🇸 · Stephane Coutu (Penn State University)🇺🇸

    The ANITA collaboration have reported observation of two anomalous events that appear to be ${\epsilon }_{\mathrm{cr}}\approx 0.6$ EeV cosmic ray showers emerging from the Earth with exit angles of $27^{\circ }$ and $35^{\circ }$, respectively. While EeV-scale upgoing showers have been anticipated as a result of astrophysical tau neutrinos converting to tau leptons during Earth passage, the observed exit angles are much steeper than expected in Standard Model (SM) scenarios. Indeed, under conservative extrapolations of the SM interactions, there is no particle that can propagate through the Earth with probability $p>10^{-6}$ at these energies and exit angles. We explore here whether "beyond the Standard Model" (BSM) particles are required to explain the ANITA events, if correctly interpreted, and conclude that they are. Seeking confirmation or refutation of the physical phenomenon of sub-EeV Earth-emergent cosmic rays in data from other facilities, we find support for the reality of the ANITA events, and three candidate analog events, among the Extremely High Energy Northern Track neutrinos of the IceCube Neutrino Observatory. Properties of the implied BSM particle are anticipated, at least in part, by those predicted for the "stau" slepton (${\tilde{\tau }}_R$) in some supersymmetric models of the fundamental interactions, wherein the stau manifests as the next-to-lowest mass supersymmetric partner particle.

    ↳ astro-ph.HEhep-ph65 citations
20. 20*

    Extending Starobinsky inflationary model in gravity and supergravity

    Sergey Ketov🇯🇵 · Maxim Khlopov🇫🇷

    We review some recent trends in the inflationary model building, the supersymmetry (SUSY) breaking, the gravitino Dark Matter (DM) and the Primordial Black Holes (PBHs) production in supergravity. The Starobinsky inflation can be embedded into supergravity when the inflaton belongs to the massive vector multiplet associated with a (spontaneously broken) $U(1)$ gauge symmetry. The SUSY and R-symmetry can be also spontaneously broken after inflation by the (standard) Polonyi mechanism. Polonyi particles and gravitinos are super heavy and can be copiously produced during inflation via the Schwinger mechanism sourced by the Universe expansion. The overproduction and instability problems can be avoided, and the positive cosmological constant (dark energy) can also be introduced. The observed abundance of the Cold Dark Matter (CDM) composed of gravitinos can be achieved in our supergravity model too, thus providing the unifying framework for inflation, supersymmetry breaking, dark energy and dark matter genesis. Our supergravity approach may also lead to a formation of primordial non-linear structures like stellar-mass-type black holes, and may include the SUSY GUTs inspired by heterotic string compactifications, unifying particle physics with quantum gravity.

    ↳ hep-thgr-qchep-phBled Workshops Phys.(2018)·15 citations
21. 21*

    Lattice QCD Can Study Parton Distribution Function Inside Hadron

    Gouranga C Nayak

    Recently we have reported that the lattice QCD can not study the physical hadron formation from the unphysical quarks and gluons because it operates the unphysical QCD Hamiltonian of all the partons inside the hadron on the physical energy eigenstate of the hadron to obtain the physical energy eigenvalue of the hadron. However, since the parton distribution function (PDF) inside the hadron is unphysical (although it is well defined in QCD), we find in this paper that the unphysical energy of all the partons inside the hadron (instead of the physical energy of the hadron) can be used to study the PDF using the lattice QCD. Hence we find that the lattice QCD can study the parton distribution function inside the hadron from the first principle.

    ↳ physics.gen-phhep-ph6 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.