High Precision Spectrometers project in CMS Krzysztof Piotrzkowski

High Precision Spectrometers project in CMS Krzysztof Piotrzkowski (UCLouvain/CERN) Introduction HPS concept and staging HPS 240 case Workshop on Forward Physics, 12 -14 December 2009, Manchester

HPS: Motivation Light Higgs boson case is compelling more than ever – exclusive production provides unique information: • Higgs quantum numbers (spin-parity filter) • Direct & precise H mass measurement (event-by-event); MH resolution of 2 Ge. V direct limits on Higgs width • Possibility of detecting H bb mode Detection of SM Higgs boson requires (very) large luminosity (sobs 0. 1 -0. 2 fb) and challenging timing detectors to keep backgrounds low (S/B 1: 2); in case of BSM physics HPS could provide discovery channels for Higgs bosons In addition, HPS offers access to ‘guaranteed’ and unique studies like electroweak physics in two-photon interactions, or new QCD phenomena in exclusive production, for example. 12/2009 K. Piotrzkowski 2

Observation of Exclusive Charmonium Production and gg → μ+μ- in pp Collisions at √s = 1. 96 Te. V 12/12/2009 K. Piotrzkowski 3

Note for CMS Management We introduced: - Detectors at 240 m - Staging concept (0/1/2) Asked CMS for actions 12/2009 K. Piotrzkowski 4

HPS proposal: Adding HPS 240 detectors • Tagging at 420 m and 240(220)m is complementary – together ~ 0. 2 -10% energy loss range is covered ! • This leads to significantly higher tagged cross sections • Both 220 and 240 m locations are ‘warm&free’ – just bare beam-pipes • At IP 5, locations at 220 m are occupied by TOTEM -> go 240 m (as ALFA in ATLAS) - it is still possible to send triggers to CMS! • One does not need to modify the LHC beamline -> can be done before HPS 420 and be treated as a proof-of-principle project + interesting physics as a bonus 12/2009 K. Piotrzkowski 5

HPS: Staging HPS requires original and challenging detector solutions – novel mechanical concept (= moving pipe 1 st used at HERA) + pico-second resolution To. F detectors HPS 420 detectors are essential for Higgs detection but require significant LHC beam-line modification (2 NCCs for Point 5) long shutdowns and significant costs HPS 240 detectors are important since can provide L 1 signals and installation require minimal intervention to LHC (NB: HPS detectors are ‘like’ a couple of new collimators, among 100…) Stage 0: Proof-of-principle experiment In close collaboration with LHC groups develop moving pipes ready for installation @240 m; test To. F detectors + associated electronics 12/2009 K. Piotrzkowski 6

HPS: Staging Stage 0: Proof-of-principle experiment Demonstrate in-situ performance of timing detectors (resolutions, resistance to backgrounds, etc) ; learn to operate near-beam detectors; characterize backgrounds etc. Stage 1: HPS 240 for CMS Add simple trackers based on CMS barrel pixels + L 1 trigger detectors; after integration of all detectors into CMS DAQ start unique studies – search for exclusive production of SUSY pairs, stringent tests of SM gauge boson sector, for example. Stage 2: Final HPS configuration Hunt for exclusive Higgs can start using ultimate detectors – new trackers and timing detectors (Note HPS stage 2 as ‘test-bench’ for CMS phase 2 DAQ/tracker + HPS 420 in L 1 is possible in phase 12/2009 K. Piotrzkowski 7 2!)

LHC Plans as announced at HCP conference, Evian, Nov 20 12/2009 K. Piotrzkowski 8

LHC Plans as announced at HCP conference, Evian, Nov 20 12/2009 K. Piotrzkowski 9

HPS schedule Very recent LHC upgrade schedule matches perfectly the HPS tentative schedule from the note: As of now this is during > 1 year LHC shutdown! 12/2009 K. Piotrzkowski 10

LHC beam-line close to 240 m TOTEM Available space of ~12 m! From Detlef: • Space above quench resistors (QRs) is not reserved yet • Space between QR and beam pipe ~ 25 cm, and space between QRs ~ 50 cm • No problem of heat load 12/2009 K. Piotrzkowski 11

Taken on 14/1/2009 CMS Q 6 ~240 m from IP 5 Qu enc h re sist ove c l a o T 12/2009 K. Piotrzkowski ors 12

HPS 420 0 m ~25 12/2009 K. Piotrzkowski 13

Forward proton acceptance @ b* = 0. 5 m HECTOR: JINST 2, P 09005 (2007) To detect forward protons for CEP of light Higgs (Mh ~ 120 Ge. V) one needs FP 420 detectors; Note: Acceptance is mostly driven by energy loss NOT scattering angle (p. T) HPS 240 essential for triggering + efficiency for HPS 240+HPS 420 ~ 2 x HPS 420 12/2009 K. Piotrzkowski 14

Acceptance for HPS 240 Preliminary – newest optics (Jerome de Favereau) Acceptance and resolutions similar and to old ‘FP 220’ HPS meeting, 2/10/2009 K. Piotrzkowski 15

HPS acceptance with newest LHC optics b* = 0. 55 m N. Schul & J. de Favereau Using two-photon spectra! Note: 2 mm approach introduce some shadowing of HPS 420 12/2009 K. Piotrzkowski 16

HPS acceptance with newest LHC optics b* = 0. 55 m Note: 2 mm approach introduce some shadowing of HPS 420 12/2009 K. Piotrzkowski 17

HPS acceptance with newest LHC optics b* = 0. 55 m Note: Acceptance changes when central system X is constrained - here |rapidity(X)| < 1. 5 12/2009 K. Piotrzkowski 18

2. 5 mm approach no dead edge 12/2009 K. Piotrzkowski 19

HPS acceptance with newest LHC optics b* = 0. 55 m Most realistic case: 2. 5 mm approach of HPS 240 and 0. 5 mm dead edge (=2 mm physical approach) 12/2009 K. Piotrzkowski 20

HPS acceptance: Recent lessons • HPS 240 approach not too close to avoid shadowing • Dead edge should be minimized at HPS 240 • It favors short pockets • For HPS 240 one pocket design should become baseline • Length of Cerenkov detectors should be minimized Present CMS pixel detector provide good resolution for stage 1 12/2009 K. Piotrzkowski 21

Stage 0 and 1 for HPS 240 Ø Stage 0/1: As final stage of moving pipe R&D install (in 2011? ) first station with fast timing detectors + position hodoscopes Ø Stage 1: After HPS approval, install two HPS_240 stations (in 2012 -13? ) with tracking based on modified CMS pixel sensors Ø Note: Good resolution in energy loss expected already for rather poor detectors – eg. For 100 um spatial resolution expect about 2% energy resolution for a 300 Ge. V loss! Ø Essential exercise for the final HPS design – handling of backgrounds, operation aspects + first (tagged) physics Ø First bremsstrahlung measurement in pp (HPS_240 +ZDC) – large cross-section ~ 10 nb (-> 1 Hz at 1033 !) – can use for fast calibration of BOTH ZDC and HPS_240; and as another way of absolute luminosity determination! Ø NOTE: Stage 1 HPS is low cost project – can be done ‘quickly’ ! 12/2009 K. Piotrzkowski 22

12/12/2009 K. Piotrzkowski 23

Two-photon physics MSSM: 100 fb-1 (no pileup) ar. Xiv: 0908. 2020 Large rates for WW HPS 240 only range

(Light) SUSY case ar. Xiv: 0806. 1097 [hep-ph] Forward detectors crucial for kinematics reconstruction (charged dilepton states only!): Unique contribution! HPS 240 accepts about 50% events !!

SUSY case with pileup Contribution to SUSY’ 09 ar. Xiv: 0910. 0202 [hep-ph]

Supersymmetric signals at high L N. Schul at SUSY’ 09: Assume 10 ps resolution on each proton HPS meeting, 2/10/2009 K. Piotrzkowski 27

Extra slides HPS meeting, 2/10/2009 K. Piotrzkowski 28

Forward proton acceptance @ b* = 0. 5 m HECTOR: JINST 2, P 09005 (2007) Similar proton lateral distributions to HPS 420 HPS meeting, 2/10/2009 K. Piotrzkowski 29