# OpenAccess

 2019-03-1911:12 [PUBDB-2019-01605] Report/Journal Article Pankov, A. A. Improved constraints on the mixing and mass of $Z'$ bosons from resonant diboson searches at the LHC at $\sqrt{s}=13$ TeV and predictions for Run II [DESY-18-170; arXiv:1809.08933] Physical review / D 98(9), 095029 (2018) [10.1103/PhysRevD.98.095029]   New neutral vector bosons Z′ decaying to charged gauge boson pairs W$^+$W$^-$ are predicted in many scenarios of new physics, including models with an extended gauge sector such as E6, left-right symmetric ZLRS′ and the sequential standard model ZSSM′. For these benchmark models we calculate and present theoretical expectations for different values of the Z′ mass M2 and mixing parameter ξ. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1910:24 [PUBDB-2019-01603] Journal Article Santra, R. Time-resolved x-ray/optical pump-probe simulations on $\mathrm{N_2}$ molecules Structural dynamics 6(2), 024101 (2019) [10.1063/1.5053995]   The dynamics of $N_2^{2+}$ dications after x-ray-induced Auger decay and their probing with a delayed infrared probe pulse are theoretically investigated based on a quantum-mechanical model including all relevant electronic states for which wave-packet calculations on ab-initio potential energy curves are performed. Our results demonstrate that the $N_2^{2+}$ yield modulated by the delay of the probe pulse contains dynamical information on the wave-packet evolution in the quasi-bound final electronic states [...] OpenAccess: PDF PDF (PDFA); 2019-03-1910:07 [PUBDB-2019-01602] Dissertation / PhD Thesis Jones, R. M. Higher-Order-Mode-based Beam Phase and Beam Position Measurements in Superconducting Accelerating Cavities at the European XFEL 183 pp. (2019) [10.3204/PUBDB-2019-01602] = Dissertation, University of Manchester, 2017   Instrumentation of higher order modes (HOMs) excited in accelerating cavities for beam phase and position inference provides a noninvasive and economical beam diagnostic. The principles and techniques for this purpose are investigated for TESLA (TeV Energy Superconducting Linear Accelerator) cavities at the injector part of the newly built European XFEL and at FLASH, two free electron laser facilities based on the TESLA technology.I have designed and instrumented unconventional beam phase monitors based on monopole modes in TESLA cavities and demonstrated a routine resolution of 0.1° with a broadband setup [...] OpenAccess: PDF PDF (PDFA); 2019-03-1811:32 [PUBDB-2019-01570] Report/Journal Article Riemann, T. Scalar 1-loop Feynman integrals as meromorphic functions in space-time dimension d [DESY 17-079, HCMUS-19-01, KW 18-004, arXiv:1812.10975] Physics letters / B 791, 257 - 264 (2019) [10.1016/j.physletb.2019.02.044]   The long-standing problem of representing the general massive one-loop Feynman integral as a meromorphic function of the space-time dimension d has been solved for the basis of scalar one- to four-point functions with indices one. In 2003 the solution of difference equations in the space-time dimension allowed to determine the necessary classes of special functions: self-energies need ordinary logarithms and Gauss hypergeometric functions $_{2}F_1$, vertices need additionally Kampé de Fériet-Appell functions $F_1$, and box integrals also Lauricella-Saran functions $F_S$ [...] OpenAccess: PDF PDF (PDFA); 2019-03-1510:39 [PUBDB-2019-01556] Dissertation / PhD Thesis Gruener, F. Study of self-modulation of an electron beam in plasma 142 pp. (2019) [10.3204/PUBDB-2019-01556] = Dissertation, University of Hamburg, 2018   The acceleration of electron beams in plasma wakefields driven by charged particlebeams is among the most promising candidates for future TeV-scale compact electronaccelerators. Currently available high energy proton beams that could serve as driverbeams in a plasma wakefeld accelerator (PWFA) are much longer than what is requiredfor efficient excitation of high-amplitude wakefields and thus for generating the desiredhigh acceleration gradients. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:57 [PUBDB-2019-01551] Preprint/Report Marquard, P. Five-Loop Static Contribution to the Gravitational Interaction Potential of Two Point Masses [arXiv:1902.11180; DESY-19-029; DO-TH-19/01]   We compute the static contribution to the gravitational interaction potential of two point masses in the velocity-independent five-loop (and 5th post-Newtonian) approximation to the harmonic coordinates effective action in a direct calculation. The computation is performed using effective field methods based on Feynman diagrams in momentum-space in $d = 3 - 2\varepsilon$ space dimensions. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:55 [PUBDB-2019-01550] Preprint/Report et al HEJ 2: High Energy Resummation for Hadron Colliders [arXiv:1902.08430; DESY-19-028; IPPP/19/13; MCnet-19-05]   We present HEJ 2, a new implementation of the High Energy Jets formalism for high-energy resummation in hadron-collider processes as a flexible Monte Carlo event generator. In combination with a conventional fixed-order event generator, HEJ 2 can be used to obtain greatly improved predictions for a number of phenomenologically important processes by adding all-order logarithmic corrections in $\hat{s}/p_\perp^2$. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:26 [PUBDB-2019-01546] Preprint/Report et al Conformal field theory and the hot phase of three-dimensional U(1) gauge theory [arXiv:1903.00491; DESY-19-027]   We study the high-temperature phase of compact U(1) gauge theory in 2+1 dimensions, comparing the results of lattice calculations with analytical predictions from the conformal-field-theory description of the low-temperature phase of the bidimensional XY model. We focus on the two-point correlation functions of probe charges and the field-strength operator, finding excellent quantitative agreement with the functional form and the continuously varying critical indices predicted by conformal field theory.. OpenAccess: PDF PDF (PDFA); 2019-03-1411:38 [PUBDB-2019-01537] Report/Journal Article et al The $O(\alpha^2)$ Initial State QED Corrections to $e^+e^-$ Annihilation to a Neutral Vector Boson Revisited [arXiv:1901.08018; DESY-18-226; DO-TH-18-30] Physics letters / B 791, 206 - 209 (2019) [10.1016/j.physletb.2019.02.038]   We calculate the non-singlet, the pure singlet contribution, and their interference term, at $O(\alpha^2)$ due to electron-pair initial state radiation to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation without any approximation. The correction is represented in terms of iterated incomplete elliptic integrals. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1411:25 [PUBDB-2019-01536] Journal Article et al Measurement of atmospheric tau neutrino appearance with IceCube DeepCore Physical review / D 99(3), 032007 (2019) [10.1103/PhysRevD.99.032007]   We present a measurement of atmospheric tau neutrino appearance from oscillations with three years of data from the DeepCore subarray of the IceCube Neutrino Observatory. This analysis uses atmospheric neutrinos from the full sky with reconstructed energies between 5.6 and 56 GeV to search for a statistical excess of cascadelike neutrino events which are the signature of $ν_τ$ interactions [...] OpenAccess: PDF PDF (PDFA);