Thu·Jun 29, 2017Thursday·June 29, 2017

1. 01*

   Drift Chamber Track Reconstruction for the P349 Antiproton Experiment

   Dominika Alfs🇵🇱

   The aim of this thesis was to perform the drift chamber calibration and charged particles 3d track reconstruction for the P349 antiproton polarization experiment. A dedicated procedures were designed, implemented and tested on the experimental data for the the D1 drift chamber. The calibration consisted of the drift time offsets determination, estimation of the initial drift time - space relations by means of the homogeneous irradiation method and the iterative procedure for the time - space relations optimization. Calibration curves for all wire planes of the detector were determined. The obtained uncertainties of the hit position reconstruction are in the range of 150 - 220 $\mu \mathrm{m}$. Furthermore, based on the prepared 3d track reconstruction angular distribution of tracks passing through the drift chamber were determined.

   ↳ physics.ins-detnucl-ex0 citations
2. 02*

   Measurement of jet $p_{\mathrm{T}}$ correlations in Pb+Pb and $pp$ collisions at $\sqrt{s_{\mathrm{NN}}}=2.76\text{ TeV}$ with the ATLAS detector

   ATLAS Collaboration

   Measurements of dijet $p_{\mathrm{T}}$ correlations in Pb+Pb and $pp$ collisions at a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=2.76\text{ TeV}$ are presented. The measurements are performed with the ATLAS detector at the Large Hadron Collider using Pb+Pb and $pp$ data samples corresponding to integrated luminosities of 0.14 nb${}^{-1}$ and 4.0 pb${}^{-1}$, respectively. Jets are reconstructed using the anti-$k_t$ algorithm with radius parameter values $R=0.3$ and $R=0.4$. A background subtraction procedure is applied to correct the jets for the large underlying event present in Pb+Pb collisions. The leading and sub-leading jet transverse momenta are denoted $p_{{\mathrm{T}}_1}$ and $p_{{\mathrm{T}}_2}$. An unfolding procedure is applied to the two-dimensional ($p_{{\mathrm{T}}_1}$, $p_{{\mathrm{T}}_2}$) distributions to account for experimental effects in the measurement of both jets. Distributions of (1/N)\mbox{\mathrm{d}} N/\mbox{\mathrm{d}} x_{\mathrm{J}}, where $x_{\mathrm{J}}=p_{{\mathrm{T}}_2}/p_{{\mathrm{T}}_1}$, are presented as a function of $p_{{\mathrm{T}}_1}$ and collision centrality. The distributions are found to be similar in peripheral Pb+Pb collisions and $pp$ collisions, but highly modified in central Pb+Pb collisions. Similar features are present in both the $R=0.3$ and $R=0.4$ results, indicating that the effects of the underlying event are properly accounted for in the measurement. The results are qualitatively consistent with expectations from partonic energy loss models.

   ↳ hep-exnucl-exPLB(2017)·73 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.