Mon·Oct 29, 2018Monday·October 29, 2018

1. 01*

   The Future of High-Energy Collider Physics

   John Ellis🇬🇧

   High-energy collider physics in the next decade will be dominated by the LHC, whose high-luminosity incarnation will take Higgs measurements and new particle searches to the next level. Several high-energy e+ e- colliders are being proposed, including the ILC (the most mature), CLIC (the highest energy) and the large circular colliders FCC-ee and CEPC (the highest luminosities for ZH production, Z pole and W+ W- threshold studies), and the latter have synergies with the 100-TeV pp collider options for the same tunnels (FCC-hh and SppC). The Higgs, the Standard Model effective field theory, dark matter and supersymmetry will be used to illustrate some of these colliders' capabilities. Large circular colliders appear the most versatile, able to explore the 10-TeV scale both directly in pp collisions and indirectly via precision measurements in e+ e- collisions.

   hep-phhep-ex8 citations
2. 02*

   TMD factorization for dijets + photon production from the dilute-dense CGC framework

   Tolga Altinoluk🇵🇱 · Renaud Boussarie🇺🇸 · Cyrille Marquet🇫🇷 · Pieter Taels🇮🇹

   We calculate the production of a photon and two jets at forward rapidity in proton-nucleus collisions, within the hybrid dilute-dense framework in the Color Glass Condensate (CGC) formalism. After obtaining the cross section for both the quark- and gluon-initiated channels, we consider the correlation limit, in which the vector sum of the transverse momenta of the three outgoing particles is small with respect to the individual transverse momenta. In this limit, the cross section simplifies considerably and can be written in a factorized form, sensitive to various unpolarized and linearly-polarized transverse-momentum-dependent gluon distribution functions (gluon TMDs). Thus, we demonstrate for the first time that the emergence of a TMD factorization formula in the correlation limit, from CGC expressions, holds beyond the previously-considered simpler $2\to 2$ processes.

   hep-phnucl-thJHEP(2019)·40 citations
3. 03*

   Minimal gauge inflation and the refined Swampland conjecture

   Seong Chan Park🇰🇷

   The refined de Sitter (dS) conjecture provides two consistency conditions for an effective theory potential of a quantum gravity theory. Any inflationary model can be checked by these conditions and minimal gauge inflation is not an exception. We develop a generic method to analyze a monotonically growing potential with an inflection point on the way to the plateau near the top such as the potential in minimal gauge inflation model and the Higgs inflation. Taking the latest observational data into account, we find the fully consistent parameter space where the model resides in the Landscape rather than in the Swampland.

   hep-phhep-thJCAP(2019)·42 citations
4. 04*

   Model-independent bounds on light pseudoscalars from rare B-meson decays

   Babette Döbrich🇨🇭 · Fatih Ertas🇩🇪 · Felix Kahlhoefer🇩🇪 · Tommaso Spadaro🇮🇹

   New light pseudoscalars, such as axion-like particles, appear in many well-motivated extensions of the Standard Model and provide an exciting target for present and future experiments. We study the experimental sensitivity for such particles by revising the CHARM exclusion contour, updating bounds from LHCb and presenting prospects for NA62 and SHiP. We first consider a simplified model of a light pseudoscalar $A$ and then propose a model-independent approach applicable to any spin-0 boson light enough to be produced in B-meson decays. As illustration, we provide upper bounds on $\text{BR}(B\to KA)\times \text{BR}(A\to {\mu }^{+}{\mu }^{-})$ as a function of the boson lifetime and mass for models that satisfy minimal flavour violation. Our results demonstrate the important complementarity between different experiments resulting from their different geometries.

   hep-phhep-exPLB(2019)·81 citations
5. 05*

   Phenomenology at the LHC of composite particles from strongly interacting Standard Model fermions via four-fermion operators of NJL type

   Roberto Leonardi🇮🇹 · Orlando Panella🇮🇹 · Francesco Romeo🇺🇸 · Alfredo Gurrola🇺🇸 · Hao Sun🇨🇳 · She-Sheng Xue🇮🇹

   A new physics scenario shows that four-fermion operators of Nambu-Jona-Lasinio (NJL) type have a strong-coupling UV fixed point, where composite fermions $F$ (bosons $\Pi$) form as bound states of three (two) SM elementary fermions and they couple to their constituents via effective contact interactions at the composite scale $\Lambda \approx \mathcal{O}$(TeV). We present a phenomenological study to investigate such composite particles at the LHC by computing the production cross sections and decay widths of composite fermions in the context of the relevant experiments at the LHC with $pp$ collisions at $\sqrt{s}=13$ TeV and $\sqrt{s}=14$ TeV. Systematically examining all the different composite particles $F$ and the signatures with which they can manifest, we found a vast spectrum of composite particles $F$ that has not yet been explored at the LHC. Recasting the recent CMS results of the resonant channel $pp\to e^{+}F\to e^{+}{e}^{-}q{\bar{q}}^{\prime }$, we find that the composite fermion mass $m_F$ below 4.25 TeV is excluded for $\Lambda$/$m_F$ = 1. We further highlight the region of parameter space where this specific composite particle $F$ can appear using 3 ab${}^{-1}$, expected by the High-Luminosity LHC, computing 3 and 5 $\sigma$ contour plots of its statistical significance.

   hep-phhep-exEPJC(2020)·12 citations
6. 06*

   Rare nonleptonic ${\bar{B}}_s^0$ decays as probes of new physics behind $b\to s\mu \bar{\mu }$ anomalies

   Gaber Faisel🇹🇷 · Jusak Tandean🇹🇼

   The anomalous results of recent measurements on various $b\to s{\mu }^{+}{\mu }^{-}$ processes could be initial evidence of physics beyond the standard model (SM). Assuming this to be the case, we entertain the possibility that the underlying new physics also affects the rare nonleptonic decays of the ${\bar{B}}_s^0$ meson. We consider in particular new physics arising from the interactions of a heavy $Z^{\prime }$ boson and investigate their influence on the decay modes ${\bar{B}}_s^0\to (\eta ,{\eta }^{\prime },\varphi )\omega$, which receive sizable QCD- and electroweak-penguin contributions. These decays are not yet observed, and their rates are estimated to be relatively small in the SM. Taking into account the pertinent constraints, we find that the $Z^{\prime }$ effects can greatly increase the rates of ${\bar{B}}_s^0\to (\eta ,\varphi )\omega$, by as much as two orders of magnitude, with respect to the SM expectations. We have previously shown that ${\bar{B}}_s^0\to (\eta ,\varphi ){\pi }^0$, with similarly suppressed SM rates, could also undergo substantial $Z^{\prime }$-induced enhancement. These rare modes can therefore serve as complementary probes of the potential new physics which may be responsible for the $b\to s{\mu }^{+}{\mu }^{-}$ anomalies.

   hep-phhep-exPRD(2019)·8 citations
7. 07*

   General analysis of polarization effects in coherent pseudoscalar mesons photo-- and electroproduction on deuteron

   G. I. Gakh🇺🇦 · A. G. Gakh🇺🇦 · E. Tomasi-Gustafsson🇫🇷

   General expressions for the unpolarized differential cross section and for various polarization observables in the coherent pseudoscalar meson photo- and electroproduction on the deuteron target have been obtained in one-photon-exchange approximation. The spin structure of the matrix element is explicitly derived in terms of structure functions. The correspondence with the helicity amplitudes is given. The polarization effects have been investigated for the case of a longitudinally polarized electron beam and vector or tensor polarized deuteron target. The polarization (vector or tensor) of the scattered deuteron for the case of unpolarized or a longitudinally polarized electron beam is also considered. In the case of the photoproduction reaction, we consider linearly, circularly or elliptically polarized photon beam. Numerical estimations have been done for the unpolarized differential cross section and for some polarization observables.

   hep-phnucl-thPRC(2019)·2 citations
8. 08*

   Reliability of Taylor expansions in QCD

   Bastian B. Brandt🇩🇪 · Gergely Endrodi🇩🇪

   We investigate the reliability of the Taylor expansion method in QCD with isospin chemical potentials using lattice simulations. By comparing the expansion of the number density to direct results, the range of validity of the leading- and next-to-leading order expansions is determined. We also elaborate on the convergence properties of the Taylor series by comparing the leading estimate for the radius of convergence to the position of the nearest singularity, i.e. the onset of pion condensation. Our results provide a handle for quantifying the uncertainties of Taylor expansions in baryon chemical potentials.

   ↳ hep-lathep-phnucl-exnucl-thPRD(2019)·46 citations
9. 09*

   Gravitational waves from global cosmic strings in quintessential inflation

   Dario Bettoni🇩🇪 · Guillem Domènech🇩🇪 · Javier Rubio🇩🇪

   The combination of non-minimal couplings to gravity with the post-inflationary kinetic-dominated era typically appearing in quintessential inflation scenarios may lead to the spontaneous symmetry breaking of internal symmetries and its eventual restoration at the onset of radiation domination. On general grounds, the breaking of these symmetries leads to the generation of short-lived topological defects that tend to produce gravitational waves until the symmetry is restored. We study here the background of gravitational waves generated by a global cosmic string network following the dynamical symmetry breaking and restoration of a $U(1)$ symmetry. The resulting power spectrum depends on the duration of the heating process and it is potentially detectable, providing a test on the existence of non-minimal couplings to gravity and the characteristic energy scale of post-inflationary physics.

   ↳ astro-ph.COgr-qchep-phJCAP(2019)·68 citations
10. 10*

    Lecture Notes on Superconductivity: Condensed Matter and QCD

    Roberto Casalbuoni🇮🇹

    Lecture notes delivered in Barcellona in the fall of 2003

    ↳ hep-thhep-ph9 citations
11. 11*

    SHM${}^{++}$: A Refinement of the Standard Halo Model for Dark Matter Searches in Light of the Gaia Sausage

    N. Wyn Evans (1)🇬🇧 · Ciaran A.J. O'Hare (2)🇪🇸 · Christopher McCabe (3) ((1), IoA, Cambridge, (2) Zaragoza, (3) KCL)🇬🇧

    Predicting signals in experiments to directly detect dark matter (DM) requires a form for the local DM velocity distribution. Hitherto, the standard halo model (SHM), in which velocities are isotropic and follow a truncated Gaussian law, has performed this job. New data, however, suggest that a substantial fraction of our stellar halo lies in a strongly radially anisotropic population, the 'Gaia Sausage'. Inspired by this recent discovery, we introduce an updated DM halo model, the SHM${}^{++}$, which includes a `Sausage' component, thus better describing the known features of our galaxy. The SHM${}^{++}$ is a simple analytic model with five parameters: the circular speed, local escape speed and local DM density, which we update to be consistent with the latest data, and two new parameters: the anisotropy and the density of DM in the Sausage. The impact of the SHM${}^{++}$ on signal models for WIMPs and axions is rather modest since the multiple changes and updates have competing effects. The largest change occurs for directional detectors which have sensitivity to the full three-dimensional velocity distribution.

    ↳ astro-ph.GAastro-ph.COhep-exhep-phPRD(2019)·300 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.