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 chambers94 BML area=600 m2 6 layers of tubes 28000 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/Psiµµ …..) (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

Pcor=K/(1/Pms± 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”).

name descriptionIdeal Ideal geometry

Misalb Misaligned + shifted/tilted B field

Misalbmat Misaligned + 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 ≤ mA ≤ 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

Segnale 200 job da 100 ev 200 job da 100 ev 200 job da 100 ev 200 job da 100 ev 200 job da 100 ev

DsPhi 900 job da 4x105 ev 900 job da 180 ev 800 job da 100 ev 800 job da 100 ev 800 job da 100 ev

DsEta 1200 job da 106 ev 1200 job da 150 ev

BsPhi 245 job da 5x105 ev 245 job da 40 ev

BsEta 360 job da 106 ev 360 job da 35 ev

τ->3μ

bb A/H/h ===> bb +-

Track efficiency from J/ΨSample of prompt J/ events, simulated with pT 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 MJPsi.

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 pT- 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) 10 -4

(1 13) 10 -4

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 AFB measurement

bb A/H/h ==> bb +-

Range studied: 15 ≤ tan ≤ 50 95 GeV ≤ mA ≤ 125 GeV (5x8 points)

Discovery potential (in the MSSM mh-max scenario)

LFV decay Forbidden in the SM

In models beyond SM (MSSM, Non universal Z’, SM+seesaw, mSugra …. ) expected BR ranging from 10-7 - 10-10

Best limits so far from the B-factories < 2 x 10-7 @ 90% C.L.

Assuming BR=2x10-7 and (W) = 20.4 0.7 nb 40 events expected in 10 fb-1

ComputingATLAS 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

Wall_time (ATLAS) comparing integrated values with others and CPU time available

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

10/1

/200

6

10/1

5/20

06

10/2

9/20

06

11/1

2/20

06

11/2

6/20

06

12/1

0/20

06

12/2

4/20

06

1/7/

2007

1/21

/200

7

2/4/

2007

2/18

/200

7

Wall_time (hours)

24*#CPU

Others

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 2006 2007 2008 2009 2010 CPU (kSi2k) 400 400 1519 2682 5009 Disk (TB) 90 165 727 1427 2555

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 05 06 07

• Permanent (fte) 11.4 11.2 12.1

• Temporary • Fellows 1 0 0• PhD Student 1 1 0 • Post-Doc 2 1 0 • Temporary contract (art 23) 3 3 3• 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.