Totem Experiment Status Report Edoardo Bossini (on behalf of the TOTEM collaboration) 131 st LHCC meeting 1
Outline CT-PPS layout and acceptance Running operation Detector commissioning CT-PPS analysis status TOTEM: analysis status Future special runs 2
CT-PPS layout CT-PPS currently running with all subdetectors installed. Four sensor technologies currently employed: For Tracking Pixel and Strip silicon detectors For timing scvd diamond and UFSD. Timing technologies hosted in the same RP! RP station involved: 210 far 220 far Timing RP Also vertical (strip) used for alignment (see next slides) 3
CT-PPS acceptance 343 437 2353 4
TS1 operation Exchange of Wiener Power supplies in sector 4/5 and 5/6 Service on cooling system temperature regulation Temperature settings and cooling performance optimized Replacement of 2 digitizer boards, new firmware for high trigger rates, replacement of cables Timing detector consolidation Vertical lifting timng RP by 2.0 mm in sector 4/5 and 5/6 Spurious beam dump by movement interlock before TS1: Software update LVDT -> successful test of RP movement system Vertical lifting has reestablished the acceptance of the timing detector after LHC beam optics changes in ip5 Continuous insertions of RPs were performed. All modifications approved by LHC MPP. 5
Collected luminosity After TS1 and after the LHC luminosity ramp-up, RP are inserted at each fill Delivered luminosity to CTPPS (11/9) ~ 17.5 /fb + 15 /fb of 2016 LHC Delivered luminosity & RP inserted ~13.5 /fb Not official (till 29/8) : LHC delivered ~ 19.5/fb CMS recorded ~ 16.8/fb RPs not inserted for ~ 1 week before TS1 (~2.8 /fb lost) 6
CT-PPS timing commissioning Relevant inefficiency (>5%) for multiple hits in the same channel Multiple hit probability(%) Diamond UFSD Due to the large data acquisition window for each trigger (125 ns integration over 5 bunches) Larger in UFSD (~6%) than in diamond sensors (~4%) Reduction to 50 ns leads to better result, but still non negligible (~2 %) inefficiency is present To shrink to 25 ns time alignment of all channels needed Performed at hardware level by tuning each channel 7
CT-PPS timing commissioning Multiple hit probability(%) 8
CT-PPS timing commissioning Signal Time Over Threshold in the expected range, can be used for time walk correction Correlation between strips and timing sensors demonstrated: Search for hit in timing sensor Reconstruct track in strip (if any) Check if track point to the expected timing pixel Diamond well centered w.r.t beam 9
Tracker detector Tracking detector hit map from may 2017 alignment run 10
Alignment data Vertical RP (strip detector) needed for relative and global alignment: Vertical beam axis through elastic hit distribution Relative alignment with tracks in the overlap region Horizontal beam axis through hit distribution on horizontal sensors (strip and pixel) 11
Clock system LHC clock is derived from CMS TCDS (Timing Control Distribution System) System delay changes over optical path is constantly monitored -> 1 measurement every 10min. Data stored to files in csv format file rotation system -> 1 file per day. Clock jitter measured at RP receiver ~2ps New clock source based on Silicon Lab 5344 chip: Zero delay mode constant phase delay between input and output Clock phase will be tuneable in ~18ps steps. 12
CT-PPS ongoing analysis Dilepton (semi-)exclusive production: ~ 9.4 fb -1 of pre-ts2 (2016) data analyzed Single-arm matching between ξ(ll) and ξ(rp) μ + μ - channel: CMS-TOTEM Physics Analysis Summary e + e - channel: Ready for review Search for exclusive di-photon production with sensitivity to four photon quartic anomalous couplings: Extraction of upper limits on the γγ γγ production cross section at 13 TeV Translating into tight constraints on anomalous 4-γ coupling Exclusive W + W /ZZ, missing mass & momentum... 13
CT-PPS first physics results Proof of operation at high luminosity with proton tagging First CT-PPS physics outcome: high significance for di-lepton observation from γγ process at this energy scale 14
TOTEM analysis Run 1 analysis to be finalized / on-going: Single diffractive jets at 8 TeV with CMS (being reviewed) Soft single diffraction @ 7 TeV Run 2 on-going analysis: Low mass resonances & glueballs - with CMS Exclusive charmonia with CMS Single diffractive J/ψ & jets with CMS Elastic scattering down to very low t (β = 2.5 km data) Luminosity independent σ tot, σ inel, σ el at 13 Tev (more on that in next slides) 15
TOTEM total cross section measurements Selection of TOTEM measurements with different energies, methodologies, systematics and data samples. 102.9 2.3 mb 101.5 2.1 mb 98.6 2.2 mb 96.07 0.92 mb 98.0 2.5 mb 95.35 1.36 mb
Upcoming results and low energy run TeV 0.9 2.76 7 8 13 TOTEM
Upcoming results and low energy run Analyses well advanced with b * =2.5 km and b * =90m. Same steps as in 8 TeV publication High precision (±0.01) ρ measurement ongoing at 13 TeV Low energy run (900 GeV), where no pp data are available, will greatly improve our understanding of the energy dependence 18
Conclusion/outlook All technologies working, RP are inserted at each fill. TS1 operations greatly improve system performance and stability. Timing sensors under commissioning. Correlation with strip tracking detector confirmed. TOT in the expected range. All tracker detector fully integrated in CMS. Relative and global alignment performed Optical clock source improved with constant phase pll. Measured Jitter at RP location ~2 ps. Analyses are ongoing both in CT-PPS and TOTEM. 1 paper from CT-PPS Future low energy run will help to understand the ρ behavior w.r.t. energy (as well the cross section) 19
20
21
b* = 0.30 m, a/2 = 175 mrad, d RP = 11.5 s + 0.3 mm b* = 0.30 m, a/2 = 175 mrad, d RP = 10.5 s + 0.3 mm ATS option 3bis b* = 0.40 m, d RP = 12 s + 0.3 mm a/2 = 150 mrad 100 mrad B1 B2 ( ) not used ( 210-N) 210-F 220-C safety limit X X X 220-F 22
CT-PPS timing commissioning Signal time (ns) Channel by channel calibration at hardware level performed: Data alignment before event building Bunch structure visible Possible to select a 25 ns acquisition window Signal time (ns) Synch with triggered bunch Signal time (ns) 23
Optical clock commissioning Check of fibers attenuation 3-4dB RMS jitter at source ~1ps RMS jitter at receivers ~2ps Jitter measurement CMS USC55 LHC- sector 56 LHC- sector 45 24