We present a new formulation of one of the major radiative corrections to the weak charge of the proton -- that arising from the axial-vector hadron part of the $γZ$ box diagram, $\Re{\rm e}\, \Box_{γZ}^{\rm A}$. This formulation, based on dispersion relations, relates the $γZ$ contributions to moments of the $F_3^{γZ}$ interference structure function. It has a clear connection to the pioneering work of Marciano and Sirlin, and enables a systematic approach to improved numerical precision. Using currently available data, the total correction from all intermediate states is $\Re{\rm e}\, \Box_{γZ}^{\rm A} = 0.0044(4)$ at zero energy, which shifts the theoretical estimate of the proton weak charge from $0.0713(8)$ to $0.0705(8)$. The energy dependence of this result, which is vital for interpreting the Q$_{\rm weak}$ experiment, is also determined.
We present the fully up-to-date calculation of the $γZ$-box correction which needs to be taken into account to determine the weak mixing angle at low energies from parity-violating electron proton scattering. We make use of neutrino and antineutrino inclusive scattering data to predict the parity-violating structure function $F_3^{γZ}$ by isospin symmetry. Our new analysis confirms previous results for the axial contribution to the $γZ$-box graph, and reduces the uncertainty by a factor of~2. In addition, we note that the presence of parity-violating photon-hadron interactions induces an addit…
The automated generation of arbitrary exclusive final states produced via photon fusion in ultraperipheral high-energy collisions of protons and/or nuclei is implemented in the MadGraph5_aMC@NLO and HelacOnia Monte Carlo codes. Cross sections are calculated in the equivalent photon approximation using $γ$ fluxes derived from electric dipole and charge form factors, and incorporating hadronic survival probabilities. Multiple examples of $γγ$ cross sections computed with this setup, named gamma-UPC, are presented for proton-proton, proton-nucleus, and nucleus-nucleus ultraperipheral collisions (…
This paper is dedicated to the study how HE particle spectra, which are measured in cosmic ray physics and astrophysics, are influenced by the specifics of collider spectrum of protons.LHC experiments are providing us with the proton spectra at very high energy (VHE) measured in center-of-mass system. A QCD phenomenological study of previous years gave us the Quark-Gluon String Model for the modeling of baryon and meson production spectra in full kinematical range from centrally produced hadrons up to very forward ones. In 1990, I have applied the method for the recalculation the collider dist…
A new type of gamma ray spectrum is predicted in a general hadronic framework if considering the gluon condensation effects in proton. The result presents the power-law with a sharp break in the gamma ray spectra at the TeV-band. We suggest to probe this GC-signature in the Earth limb gamma-ray spectra using the DArk Matter Particle Explorer and the CALorimetric Electron Telescope on orbit.
We compute the gamma-ray output of axion-mediated dark matter and derive the corresponding constraints set by recent data. In such scenarios the dark matter candidate is a Dirac fermion that pair-annihilates into axions and/or scalars. Provided that the axion decays (at least partly) into photons, these models naturally give rise to a box-shaped gamma-ray spectrum that may present two distinct phenomenological behaviours: a narrow box, resembling a line at half the dark matter mass, or a wide box, spanning an extensive energy range up to the dark matter mass. Remarkably, we find that in both c…
Anomalous quartic ZZgammagamma couplings in gamma-proton collision at the LHC
我们通过LHC的过程$p p\to pγp\to p γq Z X$研究了反常四次$ZZγγ$耦合的约束。考虑到各种前向探测器的接受度和集成LHC的光度，我们发现95%的置信水平上的异常耦合参数的界限。我们表明，这些耦合的界限是在$10^{-6}GeV^{-2}$的顺序，这是约四个数量级的限制，相对于目前的实验界限。
We calculate the differential cross section $dσ/dt$ for the diffractive photoproduction process $γp \to ρp$ and compare to recent data extracted by the CMS collaboration from ultraperipheral proton-lead collisions. Our model is based on two-gluon exchange in the nonperturbative domain. We take into account both helicity conserving and often neglected helicity-flip amplitudes in the $γ\to V$ transition. The letter can contribute at finite $t$. The shape of the differential cross section as well as the role of helicity flip processes is strongly related to the dependence of the unintegrated gluo…
The gluon condensation effect in cosmic proton-proton collisions at high energy is used to explain an excess in the positron spectrum observed by AMS. We find that this excess may originate from the GC-effect in Tycho's supernova remnant.
TXS 0506+056, a source of the extreme energy neutrino event, IceCube-170922A, was observed on 22 September 2017. The Fermi-LAT detector reported high energy (HE) $γ$-ray flare between 100 MeV and 100 GeV starting from 15 September 2017 from this source. Several attempts to trace the very high energy (VHE) gamma-ray counterparts around the IceCube-170922A resulted in no success. Only after 28 September, the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes observed the first VHE gamma-rays from the blazar above 100 GeV. The $\sim$ 41 hr survey resulted in VHE-$γ$ ray activity til…
Suppression of Theta^+(J^P=3/2^(+,-)) photoproduction from the proton
我们研究了质子和中子光生Theta^+的情况，γ N -> Kbar Theta^+。假设θ ^+的自旋和宇称为J^P = 3/2^（+，-），结果表明，与中子相比，质子的产生受到强烈抑制。这可能为CLAS实验通过反应γ p -> Kbar ^0 Theta^+发现Theta ^+的无效结果提供了一个可能的解释。
We study spectral features in the gamma-ray emission from dark matter (DM) annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with either neutralino or right-handed (RH) sneutrino DM. We perform a series of scans over the NMSSM parameter space, compute the DM annihilation cross section into two photons and the contribution of box-shaped features, and compare them with the limits derived from the Fermi-LAT search for gamma-ray lines using the latest Pass 8 data. We implement the LHC bounds on the Higgs sector and on the masses of supersymmetric particles as well as the c…
A puzzling excess in gamma-rays at GeV energies has been observed in the center of our galaxy using Fermi-LAT data. Its origin is still unknown, but it is well fitted by Weakly Interacting Massive Particles (WIMPs) annihilations into quarks with a cross section around $10^{-26}{\rm cm^3 s^{-1}}$ with masses of $20-50$~GeV, scenario which is promptly revisited. An excess favoring similar WIMP properties has also been seen in anti-protons with AMS-02 data potentially coming from the Galactic Center as well. In this work, we explore the possibility of fitting these excesses in terms of semi-annih…
Gamma-ray production in the cosmic-ray -- dark matter scattering as a probe of the axion-like particle -- proton interaction
Federal University of Pelotas（佩洛塔斯联邦大学）；CEA Saclay, Université Paris-Saclay（巴黎萨克雷大学塞莱-萨克莱法国原子能和替代能源委员会研究中心）；Universidade de São Paulo, Instituto de Física de São Carlos（圣保罗大学圣卡洛斯物理研究所）
Many models currently exist which attempt to interpret the excess of gamma rays emanating from the Galactic Center in terms of annihilating or decaying dark matter. These models typically exhibit a variety of complicated cascade mechanisms for photon production, leading to a non-trivial kinematics which obscures the physics of the underlying dark sector. In this paper, by contrast, we observe that the spectrum of the gamma-ray excess may actually exhibit an intriguing "energy-duality" invariance under $E_γ\rightarrow E_\ast^2/E_γ$ for some $E_\ast$. As we shall discuss, such an energy duality …
