Status report from the Atlas LNF group Bellisario Esposito Outline -LNF partecipation in Atlas -Detector activity and status -Preparation to the Analysis of Data -Computing -Personnel -Conclusions

Atlas LNF group Researchers Permanent: Antonelli M, Bilokon H, Cerutti F, Chiarella V, Curatolo M, Esposito B, Ferrer ML, Giovannella S, Laurelli P,Maccarrone G, Martini A, Miscetti S, Nicoletti G, Sansoni A Temporary: Beretta M, Gatti C, Wen Mei,Vilucchi E (Barone M, Kordas K, Ventura S) Technicians Permanent: Capitolo E, Pileggi G, Ponzio B, Russo V Temporary: Vassilieva T SPAS Service: Capoccia C, Cerioni S (1fte) Computing Center: Maselli D, Soprano C (1fte)

LNF partecipation in Atlas Interest in the Physics with muon signature Detector contribution: Muon precision tracking chambers R&D, final design, series production and QA/QC Facilities, construction, commissioning Contribution to the Trigger/DAQ software Test beam and cosmic test station at LNF Data Analysis and simulation studies Computing

BML MDT chambers 94 BML area=600 m2 6 layers of tubes tubes Wire positioning specification: < 20 um rms Measured Wire position fluctuation with respect to the nominal grid.

Series Production and QA/QC Facilities

Detector Activity and Status All 94 chambers installed in Atlas Positioning and sector commissioning going on (LNF Physicists, Engineers and Technicians strongly involved) Commissioning of Trigger/DAQ

Preparation to the Data Analysis Understanding the detector test beam, cosmic rays, commissioning in the pit, performance studies with data and MC Methods for in-situ calibration with known physics events (as Z  µµ, J/Psi  µµ …..) (Note CSC) Developing analysis algorithms Signal/Background separation, Integrated Luminosity Trigger strategy, Detector performance, Signal significance Standard Physics, New Physics, Early Physics Higgs (Note CSC), Supersimmetric Higgs (Note CSC) New Z Bosons, Lepton Flavour violation Z, W production J/Psi, Y production Getting ready with computing resources

Muon Spectrometer in-situ calibration Absolute Momentum Scale Alignement, B-field, material P cor =K/(1/P ms ± δs)+ΔE + δE K,δs,δE depend on eta,phi to be determined by fitting the known Z mass profile Trigger and Track Efficiency 1 μ required + 1 ID track + Z mass Check if 2nd track seen in the muon detector

MC samples for scale calibration and efficiency determination The effects of misalignment, tilted B field, and wrong knowledge of detector material have to be tested. The officially produced raw MC files (RDOs) contain events simulated with “misalbmat” geometry (including all three effects). On the Frascati Tier-2 the files were copied and reconstructed using 3 different geometries (from to “ideal” to “misalbmat”). namedescription IdealIdeal geometry MisalbMisaligned + shifted/tilted B field MisalbmatMisaligned + shifted/tilted B field + distorted material 3500 RDOs for the Z  sample and 1000 RDOs for the J/  sample reconstructed 50 events per RDO (each RDO is about 2.4 MB/evt =120 MB) The reconstruction time is about 24 s/evt, for a total recontruction time of 24x50x3~1 h per input file (for 3 different geometry conditions). With 29 CPUs it takes (full efficiency, free slots...) 1 week to complete the reconstruction.

Local event production Signal: bb A/H/h ===> bb  +  - Range: 15 ≤ tan  ≤ 50; 95 GeV ≤ m A ≤ 125 GeV; 5x8 points. Backgrounds: bbZ ==> bb  +  - (*), tt ==> bb  +  - + -, ZZ ==> bb  +  - *) can be estimated from Z=> e + e - MC events: ~ 10 M (~150k jobs) Generazione 0.2 s/ev Atlfast 1 s/ev Simulazione 4.8 min/ev Digitizzazione 15 s/ev Ricostruzione 30 s/ev Segnale200 job da 100 ev DsPhi900 job da 4x10 5 ev900 job da 180 ev800 job da 100 ev DsEta1200 job da 10 6 ev1200 job da 150 ev BsPhi245 job da 5x10 5 ev245 job da 40 ev BsEta360 job da 10 6 ev360 job da 35 ev τ->3μ bb A/H/h ===> bb  +  -

Track efficiency from J/Ψ Sample of prompt J/  events, simulated with p T cut of 6 and 4 GeV on the two muons. 50,000 events (corresponding to L ~5 pb -1 ) reconstructed. Event selection: an identified muon (ID+MS). Muon tag: an ID track with invariant mass with the identified muon close to M JPsi. Tracking efficiency: the ratio of found muon tracks divided by the number of tagged muons. The comparison of measured “from data” and true-MC efficiency is done for several slices in the p T -  plane, and for different cuts on the  2 of the tagged track. A good agreement is found for all slices and for different cuts. The study of trigger and background biases is underway.

Momentum scale from Z mass fitting  15 k events of Z    fit reconstructed Z mass  Free fit parameters: Momentum scales in Barrel and Ecap regions (  ).  folding the generated P spectra with MC resolution  (4  14)   (1  13)  M(  ) (GeV) MisalbMat

Search for extra vector boson: Z’ Preliminary study based on MC sample Z’(SSM)  (Sequential Standard Model) 1000 events M(Z’)=1 TeV (~2 fb -1 ) 1000 events M(Z’)=2 TeV (~40 fb -1 ) 95% of background comes from pp   Z  (included in the simulation). Event selection: two tracks in the muon spectrometer of opposite charge Loose cuts on track  2 (selection efficiency ~80%) Studies on-going: discovery potential for masses up to few TeV and for different models (cross sections) effect of misalignment and impact on discovery determination of Z’ spin through A FB measurement

bb A/H/h ==> bb  +  - Range studied : 15 ≤ tan  ≤ GeV ≤ m A ≤ 125 GeV (5x8 points) Discovery potential (in the MSSM m h -max scenario)

LFV decay  Forbidden in the SM In models beyond SM (MSSM, Non universal Z’, SM+seesaw, mSugra …. ) expected BR ranging from Best limits so far from the B-factories < 2 x 10 90% C.L. Assuming BR=2x10 -7 and  (W  ) = 20.4  0.7 nb 40 events expected in 10 fb -1

Computing ATLAS Computing Model Tier0, Tier1, Tier2 are the central, regional and local computing resources Centralized data processing at Tier0, Tier1 Simulation and analysis at Tier2 ATLAS-Italy Tier organisation 1 Tier1 (CNAF) 4 Tier2 (Roma1, Napoli,Milano, LNF) 1Tier2 additional (Bologna) at CNAF also considered INFN decisions 2 Tier2 (Roma1,Napoli) approved by INFN up to now The other sites (Milano, LNF) required to keep alive and active in order to be discussed later on Important ingredient in the INFN decisions is the consideration of the available infrastructure and man-power

LNF “proto” Tier2 At LNF installed and successfully operating a “proto” Tier2 ( 41 kSI2k 16TB ) Personnel:  2 (1fte) Computing center  4 (3fte) from ATLAS Activity: Atlas CSC production Local production Analysis

Tier-2 development plan Resources available are adequate for the present phase ( CSC event production, LHC not yet running) A large increase is foreseen in the course of next years Present INFN Referees plan for Atlas Tier-2 Year CPU (kSi2k) Disk (TB) The computing resources indicated are the total to be considered for all the Tier-2 ( each of the Tier-2 about ¼ of the total ) Infrastructural upgrade of the computing center at LNF is necessary to host the final configuration of computing resources envisaged

Computing center building Tier 2 A detailed design of the Power system and the Conditioning system has been made. Some upgrade of the computing center infrastructure is needed anyway independently of the Tier2. The additional cost necessary in order to make the infracture adequate for the Tier2 is 150KEuro. Infrastructure needed for the Tier2 at LNF

Personnel (1) Technical staff Group technicians 4 Temporary contracts 1 + 4(production) Visitors 2-4(production) Design Office Engineers 2 + 1(project) Workshop Electronic workshop Computing center 2 (1fte)

Personnel (2) Physicists staff Permanent (fte) Temporary Fellows PhD Student Post-Doc Temporary contract (art 23) Temporary Collaboration (art 2222) 1 1 1

Conclusions The LNF group in the many years (17)devoted to the Atlas experiment has given important contribution to the realization of the Atlas detector, thanks to the support of the Laboratory and to the expertise and the ingenuity of the staff The final goal of doing Physics at a new energy frontier, which motivated the Laboratory and each one of the participants to get involved in the Atlas experiment, is approaching and we are getting ready for it. For that to be a success the support of the Laboratory is needed in terms of man power and infrastructure.