We present a preliminary set of updated NLO parton distributions. For the first time we have a quantitative extraction of the strange quark and antiquark distributions and their uncertainties determined from CCFR and NuTeV dimuon cross sections. Additional jet data from HERA and the Tevatron improve our gluon extraction. Lepton asymmetry data and neutrino structure functions improve the flavour separation, particularly constraining the down quark valence distribution.

pdf/parton-distributions-for-the-lhc-3jcnh64voi.pdf

Parton distributions for the LHC

In this contribution, we discuss the asymptotic safety scenario for quantum gravity with a functional renormalisation group approach that disentangles dynamical metric fluctuations from the background metric. We review the state of the art in pure gravity and general gravity-matter systems. This includes the discussion of results on the existence and properties of the asymptotically safe ultraviolet fixed point, full ultraviolet-infrared trajectories with classical gravity in the infrared, and the curvature dependence of couplings also in gravity-matter systems. The results in gravity-matter systems concern the ultraviolet stability of the fixed point and the dominance of gravity fluctuations in minimally coupled gravity-matter systems. Furthermore, we discuss important physics properties such as locality of the theory, diffeomorphism invariance, background independence, unitarity, and access to observables, as well as open challenges.

/pdf/quantum-gravity-a-fluctuating-point-of-view-1x6jb0lqbi.pdf

Quantum gravity: a fluctuating point of view

We discuss new physics phenomenology of hidden scalar ($S$), pseudoscalar ($P$), vector ($V$) and axial-vector ($A$) particles coupled to nucleons and leptons, which could give contributions to proton charge radius, $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$, $^{8}\mathrm{Be}\text{\ensuremath{-}}^{4}\mathrm{He}$ anomaly and electric dipole moment (EDM) of Standard Model (SM) particles. In particular, we estimate sensitivity of $\mathrm{NA}64\ensuremath{\mu}$ experiment to observe muon missing energy events involving hidden scalar and vector particles. That analysis is based on geant4 Monte Carlo simulation of the signal process of muon scattering off target nuclei $\ensuremath{\mu}N\ensuremath{\rightarrow}\ensuremath{\mu}NS(V)$ followed by invisible boson decay into dark matter (DM) particles, $S(V)\ensuremath{\rightarrow}\ensuremath{\chi}\ensuremath{\chi}$. The existence of light sub-GeV bosons could possibly explain the muon ($g\ensuremath{-}2$) anomaly observed. We also summarize existing bounds on ATOMKI $X17({J}^{P}={0}^{\ensuremath{-}},{1}^{\ifmmode\pm\else\textpm\fi{}})$ boson coupling with neutron, proton, and electron. We implement these constraints to estimate the contribution of $P$, $V$. and $A$ particles to proton charge radius via direct 1-loop calculation of Sachs form factors. The analysis reveals the corresponding contribution is negligible. We also calculate bounds on dark axion portal couplings of dimension-five operators, which contribute to the EDMs of leptons and neutron.

Implication of hidden sub-GeV bosons for the ( g − 2 ) μ , Be 8 − He 4 anomaly, proton charge radius, EDM of fermions, and dark axion portal

A mechanism is suggested by which the dynamics of confinement could be responsible for the fermion mass matrix. In this approach the large top quark Yukawa coupling is generated naturally during confinement, while those of the other quarks and leptons stem from non-renormalizable couplings at the Planck scale and are suppressed. Below the confinement scale(s) the effective theory is minimal supersymmetric $SU(5)$ or the supersymmetric standard model. Particles in the $\bar 5$ representations of $SU(5)$ are fundamental while those in the $10$ and $5$ are composite. The standard model gauge group is weakly coupled and predictions of unification can be preserved. A hierarchy in confinement scales helps generate a hierarchical spectrum of quark and lepton masses and ensures the Kobayashi-Maskawa matrix is nearly diagonal. However, the most natural outcome is that the strange quark is heavier than the charm quark; additional structure is required to evade this conclusion. No attempt has been made to address the issues of $SU(5)$ breaking, SUSY breaking, doublet/triplet splitting or the $\mu$ parameter. While the models presented here are neither elegant nor complete, they are remarkable in that they can be analyzed without uncontrollable dynamical assumptions.

Generating a Fermion Mass Hierarchy in a Composite Supersymmetric Standard Model

extra U(1)模型におけるヒッグスボソン質量の上限

We consider an anomaly-free U(1) extension of the Standard Model with three right-handed neutrinos (RHNs) and two complex scalars, wherein the charge assignments preclude all tree-level mass terms for the neutrinos. Considering this setup, in turn, to be only a low-energy effective theory, we introduce higher-dimensional terms a la Froggatt-Nielsen to naturally generate tiny neutrino masses. One of the RHNs turns out to be very light, thereby constituting the main decay mode for the Z′ and hence relaxing the LHC dilepton resonance search constraints. The lightest RHN has a lifetime comparable to or bigger than the age of the Universe, and, hence, could account for a non-negligible fraction of the dark matter.

/pdf/neutrino-and-z-phenomenology-in-an-anomaly-free-u-1-5fj3639y8w.pdf

Neutrino and Z′ phenomenology in an anomaly-free U(1) extension: role of higher-dimensional operators

We consider an anomaly-free $\mathrm{U}(1)$ extension of the Standard Model with three right-handed neutrinos (RHNs) and two complex scalars, wherein the charge assignments preclude all tree-level mass terms for the neutrinos. Considering this setup, in turn, to be only a low-energy effective theory, we introduce higher-dimensional terms {\em a la} Froggatt-Nielsen to naturally generate tiny neutrino masses. One of the RHNs turns out to be very light, thereby constituting the main decay mode for the $Z'$ and hence relaxing the LHC dilepton resonance search constraints. This very RHN has a lifetime comparable to or bigger than the age of the Universe, and, hence, could account for a non-negligible fraction of the dark matter.

pdf/neutrino-and-z-phenomenology-in-an-anomaly-free-mathbf-u-1-4l39pv1cbg.pdf

Neutrino and $Z'$ phenomenology in an anomaly-free $\mathbf{U}(1)$ extension: role of higher-dimensional operators

We explore an anomaly-free ${\textrm U}(1)$ gauge extended beyond the Standard model (BSM) framework, to account for the baryon asymmetry of the Universe, along with arranging for tiny neutrino mass. Neutrino masses are generated via higher-dimensional operators (HDOs) involving three right-handed neutrinos (RHNs) with gauge charges ($4$, $4$ and $-5$ respectively) and two BSM scalars. This is an attractive framework as it can accommodate a keV scale dark matter, with the lightest RHN being the candidate. The remaining two RHNs are quasi-degenerate at the TeV-scale, actively participating in the process of resonant leptogenesis through their decay governed by the same set of HDOs. The RHNs being at the TeV scale, make this framework relevant for studying flavored resonant leptogenesis. This TeV-scale resonant leptogenesis, after satisfying the neutrino oscillation data, leads to interesting predictions on the Yukawa sector of the model HDOs. The thermal evolution of the baryon asymmetry has followed the experimental results rather accurately in that corner of parameter space. As a matter of fact, this TeV-scale framework which in principle relies on the low scale resonant leptogenesis typically leads to predictions that potentially can be tested at the colliders. In particular, we consider the same-sign dilepton signature that arises from the RHN pair production through the decay of heavy gauge boson of the extra ${\textrm U}(1)$.

Leptogenesis in an anomaly-free $\mathrm{U}(1)$ extension with higher-dimensional operators

Vectorlike quarks have been shown to resolve certain longstanding discrepancies pertaining to the bottom sector. We investigate, here, the prospects of identifying the existence of a topless vectorlike doublet $(B,Y)$, as is preferred by the electroweak precision measurements. Concentrating on single production, viz. ,$B\overline{b}$ with $B\ensuremath{\rightarrow}b+Z/H$ subsequently, we find that the fully hadronic decay-channel is susceptible to discovery provided jet substructure observables are used. At the 13 TeV LHC with an integrated luminosity of $300\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, a modest value of the chromomagnetic transition moments allows for the exclusion of $M\ensuremath{\lesssim}1.8(2.2)\text{ }\text{ }\mathrm{TeV}$ in the $Z$ and $H$ channels respectively.

Looking for a vectorlike B quark at the LHC using jet substructure

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Neutrino and Z′ phenomenology in an anomaly-free U(1) extension: role of higher-dimensional operators

Neutrino and $Z'$ phenomenology in an anomaly-free $\mathbf{U}(1)$ extension: role of higher-dimensional operators

Leptogenesis in an anomaly-free $\mathrm{U}(1)$ extension with higher-dimensional operators

Looking for a vectorlike B quark at the LHC using jet substructure