Isolated Charged Hadrons in HCAL Isolated charged hadrons

Isolated Charged Hadrons in HCAL Ø Isolated charged hadrons are one of the main tools for HCAL calibration with collision data. Ø Before we record enough high-momentum tracks, we can use low momentum tracks to check the relative energy scale in the different sub-detector regions. Ø The plots on the following slide demonstrate the level of agreement of the response in HE+/- and HB+/-. The agreement for the means, peak positions, and RMS for the +/- sides is Te. Txt better than 2%. Track selection: • High purity track, ptrk>5 Ge. V. • Weakly interacting in ECAL: EEM<1 Ge. V. • Isolated wrt to other tracks with p>2 Ge. V. • Isolated in ECAL. • No HCAL isolation is required (to avoid bias). Tracks near the HB/HE transition region are not used in the comparisons. Definition of response (Ehad/ptrk): • Ehad: hadronic energy measured in a radius of 35 cm around track impact on the HCAL surface. • HB and HE regions used in the comparisons: • HB- -1. 22 ≤ η ≤ 0 • HB+ 0 ≤ η ≤ 1. 22 • HE- -2. 17 ≤ η ≤ -1. 48 • HE+ 1. 48 ≤ η ≤ 2. 17

HCAL Response to Isolated Tracks in HB± and HE± mean RMS peak HB+ 0. 728± 0. 003 0. 393± 0. 003 0. 650± 0. 004 HB- 0. 737± 0. 003 0. 388± 0. 003 0. 661± 0. 004 mean RMS peak HE+ 0. 757± 0. 001 0. 453± 0. 001 0. 656± 0. 002 HE- 0. 766± 0. 001 0. 454± 0. 001 0. 669± 0. 002 Uncertainties are only statistical. Systematic uncertainties, which are under study, will dominate the error. The preliminary results show symmetric overall response in the +/- sides of HB and HE

Notes to speakers Contact: Anton Anastassov (anton. anastassov@cern. ch) Reference Material: The material has been discussed in the HCAL DPG meetings as part of the development and optimization of the HCAL calibration procedures. More details can be found in the following presentation: https: //twiki. cern. ch/twiki/pub/CMS/Hcal. Calibration. Group/iso. Track_he. Hb. Plus. Minus. Resp. pdf