First data from TOTEM experiment at LHC Fabrizio Ferro - INFN Genova Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova TOTEM phyics Total cross-section b Elastic Scattering Forward physics (with CMS) Diffraction: soft and hard (with CMS) Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova Total pp cross section Current models predict for 14 TeV: 90 – 130 mb Aim of TOTEM: ~ 1% “First year” : ~5% Luminosity independent method: COMPETE Collaboration: special optics Diffraction 2010 Fabrizio Ferro – INFN Genova

Physics with high b* optics log(|t|)/Gev2 -t = 4·10-4 0.012 0.3 2.5 Total cross section measurement at ~5 % (~1%) Elastic scattering: 0.0004<|t|< 2.5 GeV2 Soft diffraction: all masses - 65 % of diffractive protons seen Classification of inelastic events: rates & multiplicity Diffraction 2010 Fabrizio Ferro – INFN Genova

Physics with low b* Single diffraction Hits in RP220 Single diffraction ds/dM : 0.025<x<0.15 1 < M < 3 TeV s(M)/M ~ 2 - 5% Acceptance Hits in RP220 Central diffraction ds/dM : 200 < M < 1000 GeV s(M)/M ~ 2 - 5% Log M(GeV) Elastic scattering 0.5< |t| < 5 GeV2 s(|t|) ~ 0.2√ |t| Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova TOTEM detectors Telescopes: 10.5 m TAS 14 m Roman Pot stations in the LHC tunnel RP (147 m) RP (220m) Diffraction 2010 Fabrizio Ferro – INFN Genova

T1 telescope (1) 2 arms of CSCs for track and vertex reconstruction 3.1<|h|<4.7 - Df=2p Both T1 arms on the test line. Ready for installation. Diffraction 2010 Fabrizio Ferro – INFN Genova

CSC efficiencies with muons (triple coincidences) T1 telescope (2) Both arms successfully tested with pion and muon beams Pions on copper target to get many-tracks events  reconstructed hits efficiency CSC efficiencies with muons (triple coincidences) Longitudinal vertex Cu target Beam monitor frame Transverse vertex Diffraction 2010 Fabrizio Ferro – INFN Genova

T2 telescope Both arms installed and taking data 2 arms of GEMs for tracks and vertex reconstruction 3.1<|h|<4.7 - Df=2p Both arms installed and taking data Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova T2 event at 7 TeV Diffraction 2010 Fabrizio Ferro – INFN Genova

Alignment and vertex reconstruction Before RMS=1.7cm RMS=3.1m RMS=1.4cm After RMS=0.8cm RMS=1.0cm RMS=2.3m Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova h distribution Tracks pointing to vertex Statistical error only BeamPipe cone at h~5.53 Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova TOTEM Roman Pots Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova Roman pot alignment Critical and fundamental for any physics measurement To align proton detectors means: Resolve misalignments within detector assembly → methods: local track Resolve relative positions of the pot: principal information source: motor control (→ calibration, reliability, …) → method: local track based (detector overlap) Resolve position of beam (uncertainties and variations of optics): → method: profiles from physics events, Beam Halo Cross-check: Beam Position Monitors ; Alignment with collimators Resolve left-right position → method: global (elastic) track based Diffraction 2010 Fabrizio Ferro – INFN Genova

Roman Pot alignment (at 20s) Vertical alignment sectors 5-6 (IP5 minus side) sectors 4-5 (IP5 plus side) Tracks in horizontal pot Tracks in horizontal pot preliminary preliminary Diffraction 2010 Fabrizio Ferro – INFN Genova

Roman Pot alignment (at 20s) Horizontal alignment sectors 5-6 (IP5 minus side) sectors 4-5 (IP5 plus side) preliminary preliminary Halo protons Tracks in horizontal pot Tracks in vertical pot Diffraction 2010 Fabrizio Ferro – INFN Genova

“Diffractive” protons at 7 TeV preliminary TOP BOTTOM Raw distributions, no selection: Diffractive protons + background Estimated Dp/p : 0.06 - 0.12 preliminary Diffraction 2010 Fabrizio Ferro – INFN Genova

A first elastic scattering candidate RPs at 25s Run 1964.004 Event 13682 Diffraction 2010 Fabrizio Ferro – INFN Genova

Analysis and data taking still in progress Data taking with RP at 25s : collected ~ 3 M events with RP only ~ 5 M “ RP + T2 Data taking with RP at 20s : collected ~ 6 M RP + T2 Data taking with RP at 15s : under investigation with the machine Full set of systematics sources under investigation: - Alignment - Beam position - Beam divergence - Background from the machine (halo, beam gas,.....) - Multiple scattering and material interaction - Optics : uncertainty on the optical functions, crossing angle, vertex.... and in addition: - Estimate Efficiencies (trigger, track reconstruction....) - Luminosity - Physics Background & Pile-up Diffraction 2010 Fabrizio Ferro – INFN Genova

Fabrizio Ferro – INFN Genova Summary The TOTEM Detectors installed in the LHC (RP220m and T2) have completed the commissioning and are presently taking data Once that the 220m RPs will be inserted at their nominal position, TOTEM can move on to its physic program at low b*: - high mass Single & Central Diffraction - large |t| elastic scattering (0.65 < |t| < 5 GeV2) - forward density of charged particles Precise measurements of elastic, diffractive and total cross sections require high b* optics and the installation of T1 and of RP147m - Elastic scattering in a wider |t| range - Diffractive physics over a larger rapidity range 3.1 <|h |< 6.5 - Single and Central Diffraction at any mass - Measurement of stot with a precision of ~ 5 % (1%) Diffraction 2010 Fabrizio Ferro – INFN Genova