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Totem Experiment Status Report
Edoardo Bossini
(on behalf of the TOTEM collaboration)
131st LHCC meeting
1
Outline
CT-PPS layout and acceptance Running operation Detector commissioning CT-PPS analysis status TOTEM: analysis status Future special runs
2 LHCC Open Session, 13 September 2017
LHCC Open Session, 13 September 2017
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
4
CT-PPS acceptance
343 2353
437
LHCC Open Session, 13 September 2017
5
TS1 operation
Replacement of 2 digitizer boards, new firmware for high trigger rates, replacement of cables Vertical lifting timng RP by 2.0 mm in sector 4/5 and 5/6
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.
Temperature settings and cooling performance optimized
Exchange of Wiener Power supplies in sector 4/5 and 5/6 Service on cooling system – temperature regulation
Spurious beam dump by movement
interlock before TS1: Software update LVDT -> successful test of RP movement system
Timing detector consolidation
LHCC Open Session, 13 September 2017
6
Delivered luminosity to CTPPS (11/9) ~ 17.5 /fb
RPs not inserted for
~ 1 week before
TS1 (~2.8 /fb lost)
Not official (till 29/8) :
LHC delivered ~ 19.5/fb
CMS recorded ~ 16.8/fb
After TS1 and after the LHC luminosity ramp-up, RP are inserted at each fill
LHC Delivered luminosity &
RP inserted ~13.5 /fb
Collected luminosity
+ 15 /fb of 2016
LHCC Open Session, 13 September 2017
7
CT-PPS timing commissioning
• 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
Relevant inefficiency (>5%) for multiple hits in the same channel
UFSD Diamond
To shrink to 25 ns time alignment of all channels needed
Performed at hardware level by tuning each channel
LHCC Open Session, 13 September 2017
Multiple hit probability(%)
8
CT-PPS timing commissioning
LHCC Open Session, 13 September 2017
Multiple hit probability(%)
9
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
Signal Time Over Threshold in the expected range, can be used for time walk correction
CT-PPS timing commissioning
10
Tracker detector
Tracking detector hit map from may 2017 alignment run
11
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)
LHCC Open Session, 13 September 2017
12
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
Clock system
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.
LHCC Open Session, 13 September 2017
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 LHCC Open Session, 13 September 2017
14
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
LHCC Open Session, 13 September 2017
TOTEM analysis
15
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 𝜎𝑡𝑜𝑡, 𝜎𝑖𝑛𝑒𝑙 , 𝜎𝑒𝑙 at 13 Tev
(more on that in next slides)
LHCC Open Session, 13 September 2017
98.0 2.5 mb
98.6 2.2 mb
95.35 1.36 mb
96.07 0.92 mb
101.5 2.1 mb
102.9 2.3 mb
LHCC Open Session, 13 September 2017
TOTEM total cross section measurements
Selection of
TOTEM
measurements with
different energies,
methodologies,
systematics and
data samples.
7 8 2.76 0.9 TeV
TOTEM
Upcoming results and low energy run
13
Analyses well advanced with b*=2.5 km and b*=90m. Same steps as in 8 TeV publication
Upcoming results and low energy run
18
Low energy run (900 GeV), where no pp data are available, will greatly improve our understanding of the energy dependence
High precision (±0.01) 𝜌 measurement ongoing at 13 TeV
LHCC Open Session, 13 September 2017
19
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)
LHCC Open Session, 13 September 2017
20
21
22
( 210-N)
210-F
220-C
B1 B2
220-F safety limit
( ) not used
X
a/2 = 150 mrad 100 mrad
X X
ATS “option 3bis”
b* = 0.40 m,
dRP = 12 s + 0.3 mm
b* = 0.30 m, a/2 = 175 mrad,
dRP = 11.5 s + 0.3 mm
b* = 0.30 m, a/2 = 175 mrad,
dRP = 10.5 s + 0.3 mm
23 Synch with triggered bunch
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) Signal time (ns)
Signal time (ns)
CT-PPS timing commissioning
Optical clock commissioning
– Check of fibers attenuation 3-4dB
– RMS jitter at source ~1ps
– RMS jitter at receivers ~2ps
24
CMS USC55
LHC- sector 56
Jitter measurement
LHC- sector 45