フェルミ研ドレル・ヤン実験SeaQuestのテストラン結果 東工大理、KEKA、理研B、山形大理C 宮坂翔、柴田利明、中野健一、Florian Sanftl、澤田真也A、 後藤雄二B、宮地義之C、他SeaQuest Collaboration Contents • SeaQuest experiment • SeaQuest spectrometer • Commissioning run • Performance of the detectors • Splat event • Schedule in coming year • New St.3- construction • Summary 2015/10/1 JPS meeting 2012 Autumn 1 SeaQuest experiment • SeaQuest experiment will extend the x region of Drell-Yan measurement . • 𝑑 𝑥 𝑢 𝑥 for 0.1 ≤ 𝑥 ≤ 0.45 • SeaQuest uses a 120 GeV proton beam. • Drell-Yan is a perfect tool to probe Anti-Quarks Beam Energy: 120 GeV / 800 GeV 2015/10/1 JPS meeting 2012 Autumn 2 SeaQuest spectrometer St.3+ DC St.3- DC Beam Drawing: T. O’Connor and K. Bailey 2015/10/1 JPS meeting 2012 Autumn 3 Commissioning run • Late February 2012 – April 30th 2012 – 120 GeV/c protons, 19ns intervals (53 MHz) – Beam intensity:1E12p/s, 5s spill at 1 minute intervals • First muon incident by proton beam was observed on March 8th • Typical problem were solved in March. • Target commissioning – 7targets (H2, Empty Flask, D2, “no target”, Fe, C, W) – Successfully done • Detector commissioning (Hodoscope + Drift chamber) – mapping, noise & hot channel • Trigger & DAQ – Large hit multiplicities termed “splat events” 2015/10/1 JPS meeting 2012 Autumn 4 Performance of drift chambers • No trip with at most 1.3E12 p/s . • Hot channel, Dead channel Station Dead channels Hot channels Station 1 DC 66 0 Station 2 DC 1 0 Station 3+ DC 2 0 Station 3- DC 5 0 HV 供給部分の故障 2015/10/1 JPS meeting 2012 Autumn 5 Performance of drift chambers Magnet on + - • Muon hit distribution 2015/10/1 JPS meeting 2012 Autumn Magnet off 6 Performance of drift chambers • Station 1 DC – Dead region, old – New Station 1 • Station 2 DC • works are on-going • Generate tracking algorithm • Drift chamber alignment • Calibration – Works well • Station 3+ DC – Works well • Station 3- DC – Gas leak, old – New Station 3New St.3- drift chamber being constructed 2015/10/1 JPS meeting 2012 Autumn 7 “Splat” event • Large number of hits on all the spectrometer (“Splat”) • Trigger hodoscopes to see the time structure of beam intensity Event Display – Sizable 60Hz components – Main injector power supply? • “Splat block” was applied Splat block: Turn off triggers during high intensity beam based on an integral of beam intensity ~1.5 million di-muon events were recorded 2015/10/1 JPS meeting 2012 Autumn 8 Schedule in coming year 2012/ May Commissioning run 2013/ May Upgrade Physics run (2 years) • Upgraded Stations 1 and 3- will expand acceptance to larger xt • Zero suppressed TDCs – improve live time significantly. • Beamline monitor is funded – Feedback to the accelerator control room – Generate DAQ veto – Produce accurate luminosity • Physics run will start in May 2013 2015/10/1 JPS meeting 2012 Autumn 9 New Station 3- DC construction 2015/10/1 JPS meeting 2012 Autumn 10 Summary • SeaQuest is measuring 𝑑 𝑥 𝑢 𝑥 in the extended x region, 0.1 ≤ 𝑥 ≤ 0.45 with Drell-Yan process • 2 months of commissioning run was successfully done • The detectors were working well with average 0.4-13E12 p/s • “Splat block” trigger logic was developed to avoid large hits events (“splat” event). – ~1.5 million di-muon events were recorded for physics analysis • Calibration & alignment of drift chambers are on-going. • Physics run will start in May 2013. 2015/10/1 JPS meeting 2012 Autumn 11 Backup slide 2015/10/1 JPS meeting 2012 Autumn 12 Splat-Block • Goal: Turn off triggers during high intensity beam based on an integral of beam intensity • Problem: No spill-by-spill intensity monitor independent of targets— used hodoscopes Cartoon • Counted total number of hits for n buckets before and after the trigger. • Blocked triggers this running count was above a threshold 2015/10/1 JPS meeting 2012 Autumn 13 Hit distributions with magnet off 2015/10/1 JPS meeting 2012 Autumn 14 Occupancy • Occupancy on drift chambers – – – – Definition of the occupancy for each layer in each event # of hits[chamber][plane] / # of elements[chamber][plane] Definition of the occupancy for each drift chamber in each run Sum of # of hits[chamber] / ( # of elements[chamber] * # of events) Occupancy on the 3rd drift chamber Occupancy on the 1st drift chamber Run dependence on the occupancy Occupancy depends on the beam intensity and splat block threshold 2015/10/1 JPS meeting 2012 Autumn 15 • • • • • Occupancy for each layers Definition of occupancy[chamber][plane] = # of hits[chamber][plane] / # of elements[chamber][plane] Run 2173, trigger = FPGA 1 (di-muon trigger) RemoveAfterPulse and HodoInTimeCut was applied Y axis: count, X axis : Occupancy DC1 DC2 DC3p DC3m 2015/10/1 Occupancy study 16 Occupancy with single-muon-trigger 2015/10/1 JPS meeting 2012 Autumn 17 • Correlation to run • Y axis: Occupancy for each chamber (mean value), X axis: Run ID DC1 DC2 DC2 DC3p DC3m DC3m • With FPGA2(single trigger) (Run: 2166, 2167, 2168), the occupancy was low. • 2015/10/1 It is because of trigger type. Occupancy study 18 Comparing run2173 & run 1705 • • Beam intensity = 6E11, Trigger type = di-muon trigger # of event: run2173…23641, run1705… 20386 2015/10/1 Occupancy study 19 Due to the splat block, the occupancy was suppressed. 2015/10/1 Occupancy study 20 2015/10/1 JPS meeting 2012 Autumn 21 Drift Chambers • High voltages applied were stable • Wires were stable. Only few wires in St.1 DC was broken and fixed soon in the beginning of the run. • Typical issues with mapping is resolved. • Hot channel and dead channel were found and fixed. • St.1 DC- Vplane has dead region (~60 channels) • St.3 minus DC had a gas leak problem Ar:CO2 was used last 2 weeks. • Efficiency analysis needs to be done. • Calibration is on-going. • T0 was defined preliminary, further study is being done • New Station 1 and Station3- chambers for next run! 2015/10/1 Polarized Drell-Yan Meeting @Yamagata 22 Readout electronics for drift chambers Wire chamber Amplifier card (ASDQ card) Amplifier Card Control Board (LS board) TDC To DAQ Noise PC • Set threshold • Send test pulse • All systems worked. • Communication problem between Control room (PC) and the Amplifier card control board Set independent network • Feedback from TDC caused noise Ferrite core was attached to remove the noise. 2015/10/1 Polarized Drell-Yan Meeting @Yamagata 23 Hodoscopes Very stable hodoscope performance from the beginning of Run I to its end ● Efficiency: ○ PMT voltages adjusted according to the hit ratios, indicating an (plane) efficiency of 98%99% (H1 only 90%) ○ Additional runs recorded for further detailed efficiency studies using full track reconstruction ● Timing: ○ Adjusted by varying cable length between patch panel and amp. / discrim. ○ Large fluctuations (+/- 7ns) in H4 (mean timers? work in progress!) ○ Pulse width adjusted (10ns < width < 15ns) 2015/10/1 St. 1 Hodoscopes ● Matrix1 H1 ● Contains More lower-occupancy events Needs to be understood Polarized Drell-Yan Meeting @Yamagata 24 Expected Mass Spectrum • How is the nucleon sea generated? Filter out resonances, and focus on DY. Mass spectra from E866/NuSea ECT* Conference, Trento, Italy May 2012 Nuclear Modification Nuclear Modification in DIS - Shadowing at low x - Enhancement below x ~0.3 - Suppression at larger x - Structure functions include both quark and anti-quark contributions - Measured for a broad range of targets (Ann. Rev. Nucl. Part. Phys., Geesaman, Sato and Thomas) Nuclear Modification in Drell-Yan (E772) - Drell-Yan accesses the anti-quark component - Binding mediated by pion exchange - Exchanged mesons contain anti-quarks enhancement PRL 64 (1990) 2479 No evidence of anti-quark enhancement in nuclei where did the pions go? 26 ECT* Conference, Trento, Italy May 2012 Nuclear Modification: E906 Nuclear Targets: Carbon, Iron, Tungsten • Nuclear Modification- complementary with DIS, extends previous Drell-Yan measurements – Extend to x ~ 0.45 • E772: 800GeV proton beam • Models must explain both Drell-Yan and DIS. 27 ECT* Conference, Trento, Italy May 2012 Why J/? • Are gluon distributions similar between p and n? x) J/ suppression in QGP g n ( • cc deconfinement 1? – J/ suppression against multiple effects: ( x) g pcompeting Absorption, CNM induced nuclear dependence Often assumed, but not necessarily fundamental annihilationfusion dimuon pair • qqgluon-gluon | 2 x 2 1 1 g ndx( x 2) 1 1 x 2 2 g x pu ( x2) DY J / pd pd J / DY pp pp 1 2 ECT* Conference, Trento, Italy May 2012 J/ Production: p-d, p-p • gluon-gluon fusion pd 1 1 g n x pp 2 g p x 2 Lingyan Zhu et al., PRL, 100 (2008) 062301 (arXiv: 0710.2344) • Gluon distributions between p and n are very similar • E866: Upsilon production • E906: J/ production ECT* Conference, Trento, Italy May 2012 Again, what about bound systems? • cc deconfinement J/ suppression in QGP – J/ suppression during QGP formation competing against multiple effects: absorption, energy loss within nuclei, etc How can we understand these “other processes”? ECT* Conference, Trento, Italy May 2012 J/ Nuclear Dependence A N A Suppression of J/ yield per nucleon • absorption ~ xF=0? – cc dissociation through interaction within nucleus or with comoving secondaries • parton/gluon energy loss? – loss in both initial and final states dE / dx q, g q q Cannot account for the suppression remains a mystery ECT* Conference, Trento, Italy May 2012 Partonic Energy Loss: pA1/pA2 • An understanding of partonic energy loss in both cold and hot nuclear matter is paramount to elucidating RHIC data. • Energy loss through cold nuclear matter • Pre-interaction parton moves through cold nuclear matter and loses energy • Apparent (reconstructed) kinematic values (x1 or xF)is shifted • Fit shift in x1 relative to deuterium (E906) Models: • Galvin and Milana • Brodsky and Hoyer • Baier et al. 32 ECT* Conference, Trento, Italy May 2012 •• Energy 1/s reveal no energy Fits on loss E866~data – larger at 120 GeV loss. • Correct forstatistics shadowing with DIS Sufficient to remove shadowing contribution – X2 anti-correlates withforx1low andxx2F shadowing contributions at large x1 • Measurements instead of limits – Caveat: A correction must be made for shadowing because of x1—x2 correlations – E866 used an empirical correction based on EKS fit to DIS and DrellYan. • Better data outside of shadowing region needed E906 expected uncertainties Shadowing region removed LW10504 33 ECT* Conference, Trento, Italy May 2012 Drell-Yan fixed target experiments at Fermilab • What is the structure of the nucleon? ➡ What is d / u ? ➡ What is the origin of the sea quarks? ➡ What is the high x structure of the proton? • What is the structure of nucleonic matter? ➡ Where are the nuclear pions? ➡ Is anti-shadowing a valence effect? • Do colored partons lose energy in cold nuclear matter? • SeaQuest: 2012-2014 ➡ significant increase in physics reach • Beyond SeaQuest ➡ Polarized Drell-Yan ➡ Pionic Drell-Yan 34 Tracking • • • • Removing off-time hits Track seeding Fitting Tracking Frame work over view & status of sagitta Status of Kalman filter 2015/10/1 JPS meeting 2012 Autumn 35 Drift chamber performance • TDC distribution • RT curve from the TDC distribution • Efficiency curve (single muon with low intensity beam) 2015/10/1 JPS meeting 2012 Autumn 36 Recorded event status • Number of trigger events • Number of accepted events with FPGA1 (Dimuon trigger) 2015/10/1 JPS meeting 2012 Autumn 37 2015/10/1 JPS meeting 2012 Autumn 38 2015/10/1 JPS meeting 2012 Autumn 39
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