Electrodisintegration of Deuteron into Dark Matter and Proton Close to Threshold

We discuss an investigation of the dark matter decay modes of the neutron, proposed by Fornal and Grinstein (2018–2020), Berezhiani (2017, 2018) and Ivanov et al. (2018) for solution of the neutron lifetime anomaly problem, through the analysis of the electrodisintegration of the deuteron d into dark matter fermions χ and protons p close to threshold. We calculate the triple-differential cross section for the reaction e−+d→χ+p+e− and propose to search for such a dark matter channel in coincidence experiments on the electrodisintegration of the deuteron e−+d→n+p+e− into neutrons n and protons close to threshold with outgoing electrons, protons, and neutrons in coincidence. An absence of neutron signals should testify to a detection of dark matter fermions.

Measurements of triple-differential cross sections for inclusive isolated-photon+jet events in $$\mathrm{p}\mathrm{p}$$ collisions at $$\sqrt{s} = 8\,\text {TeV} $$

Measurements are presented of the triple-differential cross section for inclusive isolated-photon+jet events in $$\mathrm{p}\mathrm{p}$$pp collisions at $$\sqrt{s} = 8$$s=8 TeV as a function of photon transverse momentum ($$p_{\mathrm {T}} ^{{\upgamma {}{}}}$$pTγ), photon pseudorapidity ($$\eta ^{{\upgamma {}{}}}$$ηγ), and jet pseudorapidity ($$\eta ^{\text {jet}}$$ηjet). The data correspond to an integrated luminosity of $$19.7{\,\text {fb}^{-1}} $$19.7fb-1 that probe a broad range of the available phase space, for $$|\eta ^{{\upgamma {}{}}} |<1.44$$|ηγ|<1.44 and $$1.57<|\eta ^{{\upgamma {}{}}} |<2.50$$1.57<|ηγ|<2.50, $$|\eta ^{\text {jet}} |<2.5$$|ηjet|<2.5, $$40< p_{\mathrm {T}} ^{{\upgamma {}{}}}<1000$$40<pTγ<1000$$\,\text {GeV}$$GeV, and jet transverse momentum, $$p_{\mathrm {T}} ^{\text {jet}}$$pTjet, > 25$$\,\text {GeV}$$GeV. The measurements are compared to next-to-leading order perturbative quantum chromodynamics calculations, which reproduce the data within uncertainties.

Laser-Assisted (e, 2e) Collisions in the Symmetric/Asymmetric Coplanar Geometry

In this review, we present a comprehensive survey of laser-assisted (e, 2e) reactions. The influence of a laser field on the dynamics of (e, 2e) collisions in atomic hydrogen is analyzed in the symmetric and asymmetric coplanar geometries. Particular attention is devoted to the construction of the dressed (laser-modified) target wave functions, in both the initial and final states. The calculation is performed in the framework of Coulomb-Volkov-Born approximation, where the initial and final electrons are described by Volkov wave functions, while the interaction of the incident electron with the target atom is treated in the first and the second Born approximation. The state of the ejected electron is described by a Volkov/Coulomb-Volkov wave function. A detailed account is also given of the techniques we have used to evaluate the scattering amplitudes. The influence of the laser parameters (frequency, intensity, and direction of polarization) on the angular distribution of the ejected electron is discussed, and a number of illustrative examples are given. The structure of the triple differential cross section in the vicinity of resonances is also analyzed.