JINR participation, achievements, short- and long-term plans

1. The ATLAS Physics Program JINR participation, achievements, short- and long-term plans Diameter 25 m Barrel toroid length 26 m End-cap end-wall chamber span 46 m Overall weight 7000 Tons Bednyakov V.A., HS07

2. Collisions at the LHC Rare events! Slide by T. Virdee

3. An Aerial View of Point-1 (Across the street from the CERN main entrance)

4. The Underground Cavern at Pit-1 for the ATLAS Detector

5. JINR ATLAS History The proposal on the participation of the JINR team in ATLAS was firstly presented in 1995. The PAC recommended this project for approval on 24 November 1995. Further on status reports on this projects have been regularly (yearly) presented at PAC and JINR Scientific Council meetings. In 1995, 6567 kUSD+140 kHours of workshop were requested, including 4069 kUSD from the JINR budget Since 1995

6. The ATLAS detector Over the last decade JINR-ATLAS team was deeply involved in designing, construction, tests and assembly of the major systems of ATLAS: Inner Detector Tile Calorimeter Liquid Argon End Cap Calorimeter Muon detector Common Items (Toroid Warm Structure and others) Participation in the Physics Program was always considered as the most important target. Till 2003 this work has been performed mainly in “background” regime, essentially based on individual efforts, promoted with limited resources case-by-case (as well as for software developments and general computing infrastructure of ATLAS).

7. ATLAS costs: 15 x 12 x 100 x 6000 = 1.08 108 CHF

8. JINR Workshops on the ATLAS Physics • Early 2004 the JINR-ATLAS team management decided to establish a regular framework (series of workshops) to promote physics-oriented activities at home, aimed to: • Open the door for new ideas (also attract new collaborators, interested in future physics at LHC); • Monitoring of ongoing activities and select most promising ones to provide the necessary support, in particular for visiting conferences and dedicated ATLAS meetings; • Enrich “home community” by involving physicists from JINR member countries who have less possibilities in computing and networking, to make JINR-ATLAS resources and experience widely available; • Keep people informed about recent software developments and dedicated computing infrastructure at JINR. • Web site: http://www.atlas-jinr.ru/

9. Main ATLAS Physical topics • Standard ModelPhysics • Higgs Boson Physics • SUSY Physics • Exotics Physics • Top Quark Physics • Heavy Ions Physics • B Physics

10. JINR ATLAS Physics team What we are doing

11. SANC Project SANC (Support of Analytical and Numerical Calculations for Experiments at Colliders). http://brg.jinr.ru/ D.Bardin, L.Kalinovskaya, P.Christova, et al (DLNP, JINR), A.Arbuzov, S.Bondarenko (BLTP, JINR). This very ambitious project starts to produce applications (generators, etc) which allow investigations of prospects for observation of the physical phenomena at the LHC with ATLAS detector.

12. SANC

13. SANC, 2007

14. Higgs boson(s) Search for the SM Higgs boson via decay H→4μ. Full ATLAS simulation, etc. G.Chelkov, I.Boyko, K.Nikolaev, et al Search for Higgs boson with mass 115-160 GeV by means of decay H->Z+gamma and Z->2l within ATLAS software APHENA. (Usubov et al). Search for Higgs boson (400-1000 GeV) decaying H->ZZ->lljj and being produced via vector boson fusion (Usubov, Kultchitski, et al). Seach for charged Higgs boson via tau-nu_tau decay (Chelkov, et al.) Study of associative production of Higgs boson and top-antitop pair .

15. Higgs boson(s) JINR

16. Higgs boson(s) Search for the SM Higgs boson via decay H→4μ. Full ATLAS simulation. G.Chelkov, I.Boyko, K.Nikolaev, et al • SIGNAL: At CERN with SANC generator (with 1-loop corrections and quantum effects of final state muon identity, for the 1st time) 30 000 H→ decays were generated for MH=130, 160 GeV/c2. For comparison 10 000 H→ 4 decays were generated with PYTHIA. • BACKGROUND: With PYTHIA (and ACERMC) generators 30 000 background events for pp→ZZ, pp→Zbb, with 4 final state muons were simulated. Single Z boson coincidence events “Z+Z” were also simulated. Almost all background events (1/3 of all data) were simulated at LIT farm in Dubna, where modern (the latest versions) ATLAS software are installed. • Detector simulation and event reconstruction were carried out completely within modern ALTAS software (C++, ATHENA, GEANT-4, AOD, Root). The results were compared with results obtained earlier (with Fortran, ATLSIM, GEANT-3, HBOOK). CERN and Dubna events (signal and background) were developed in the same manner. The CERN and Dubna simulation and analysis gave almost the same results.

17. Higgs boson, H→4μ Reconstructed events 130 GeV 160 GeV

18. Higgs boson, H→4μ GeneratorSANC predicts higher than PYTHIA number of selected decays H→(about 10-15%). There are two reasons: a higher selection efficiency and larger predicted width of the decay. The “golden channel” H4leptons is one of the most promissing for the early discovery. For the light Higgs (120-160 GeV) the signal is low (tens events per year), but the selection efficiency is high and the background is almost zero. The full simulation study shows that H4μ alone ensures a ~5σ discovery after one year of nominal luminosity. Completed

19. Higgs boson(s) to search for Higgs decay

20. Higgs boson, H→Zγ, etc Search for Higgs boson with mass 115-160 GeV by means of decay H->Z+gamma and Z->2l within ATLAS software APHENA. (Usubov et al). to be completed in 2007

21. Higgs boson(s) 1) Search for Higgs boson with mass 115-160 GeV/c by means of associative production of Higgs and Gauge Bosons (pp→W(Z)+H+X) and Higgs decay into bb-pair (H→2b→2b-jets). 2) Study the ATLAS large-mass Higgs discovery potential by means of reactions H→2W→2lν, H→2W→lνjj and H→2Z→2lν, H→2Z→lljj. Proposals rely on the Higgs boson production via the Vector Boson Fusion mechanism (the two accompanying forward jets allow very good background reduction) and on the maximal Higgs decay rates into WW- or ZZ-pair at M=400—1000 GeV. One needs a Higgs Coherence !

22. What IS this Higgs Coherence? Higgs boson main decay channels (in SM and beyond): • H • HWW* • H • H4leptons • pp  ttH+X, Hbb,  • + Higgs properties (self couplings) … Our potential important task isto check – How the Higgs boson decaying, for example, into 4 muons “shows” itself in the other allowed decays (into 2 photons, bb-pair, etc)? One needs this for the cross-check and the SM EWSB: Is this Higgs the same one, or some another one?

23. Top quark physics Verification of the top-quark charge (is it +2/3 or -4/3 ?): ATLAS will be able to verify top quark charge after analyzing of data taken 1-2 weeks of LHC operation. Search for narrow neutral resonance state (like Z‘ boson) decaying into the top-antitop pairs on the basis of ATLAS top WG data challenge (Khramov, Tonojan. Bednyakov, Rusakovich). Accurate investigation of single top quark production at LHC (in the SANC framework by Bardin et al.) Study of associative production of Higgs boson and top-antitop pair .

24. Top quark physics Verification of the of the top-quark charge (is it +2/3 ?): ATLAS will be able to verify top quark charge after analyzing of data taken 1-2 weeks of LHC operation The work was presented at ATLAS Top WG Meeting (23 March 2006). The article was submitted to ATLAS Notes. Completed

25. Top quark physics Completed 5σ discovery level

26. Higgs boson, pp→Htt, etc Started search for Higgs boson production together with top-antitop pair pp→Htt (within ATLAS software by Akhmedov, Zorin and Titkova). Higgs boson mass reconstruction via electron-positron pair within EventView software and Root 5.14 was performed. Early stage

27. Exotics, Spin-2 gravitons (EDs) The search for and identification of the graviton-like Kaluza-Klein states in the lepton-pair production at LHC via newCENTER-EDGE ASYMMETRY was proposed by A.Pankov (Gomel). The A_CE allows isolation of spin-2 graviton contribution --unique graviton exchange signature. PYTHIA+ADD

28. Exotics, LFV Study of rare LFV tau decays in ATLAS: τ  μμμ and τ  μγ V.Zhuravlov et al Sources of t leptons at LHC 1 year of low luminosity = 10 fb-1 ATLAS sensitivity is about 10-8for τ  μμμ (better x10 of current limit) 10-7 for τ  μγ

29. Exotics, Monopol Two-photon production and detection of the monopole-antimonopole pairs at LHC Yu. Kurochkin, I.Satsunkevich, D. Shuolkavy, S. Yanush (Minsk), V. Kukhtin, Yu. Kultchitski et al (JINR) Large ionization, like nucleus with Z=70

30. Search for gluinos with ATLAS g + g → gluino + gluino 1 pb m0 = 1400 GeV m1/2 = 180 GeV A = 0 sign(μ) = +1 tanβ = 30 SIGNATURE:4 b-jets + 4 muons + Etmiss Pythia within ATHENA, B-vertex taging LARGE! Almost background-less 150 events/year

31. SUSY, Gluinos

32. SUSY, Gluinos Gluinos can be observed and SUSY parameters can be separated m1/2

33. SUSY 1. Study (full simulation) of prospects for registration (with ATLAS) the SUSY gluinos (at very specific and very promising EGRET MSSM region) by means of two main gluino decay channels (4b-quarks+4leptons+E_missing and 4b-quarks+2jets+2leptons-E_missing). 2. Search for and investigation of (via fast and full detector simulations) all possible background processes (QCD, qq(gg)->4b+2l+2q, etc) for the above-mentioned SUSY process. Study of influence of relevant miss-tagging of b-jets and muons. 3. Study of prospects of registration of “weak SUSY” processes at the same EGRET MSSM region (complimentary to the above-mentioned gluino production). In these processes one expects, for example, 3leptons+neutrino+E_missing (due to the two lightest neutralinos which escape detection) and one isolated lepton (or jet) accompanied by (very) large missed “transverse” energy (due to W boson decay into neutraino and charghino). Both (gluino and “weak”) investigations are very important for the coherent SUSY search strategy. (E.Khramov, V.Bednyakov, Yu.Budagov, A.Gladyshev, D.Kazakov, J.Khubua, S.Karpov, I.Titkova + students+ CERN colleagues)

34. SUSY Exotics Study of R-hadrons detection possibility with ATLAS V.Smakova, G.Chelkov, R.Leitner Big mass >100 GeV R-hadron -- passive gluino + interacting π/ρ/K/p/n cloud In a nuclear interaction, they may flip charge and baryon number. Signatures: • High transverse momentum for charged hadrons • Heavy ionization in the tracking system • Missing transverse energy due to large R-hadron mass • “Small” E/p distribution • Large time-of-flight, measurable with the muon chambers and TileCal

35. Heavy Ions Jet quenching is one of the probe of the Condensed Nuclear Matter(QG-Plasma) V.Pozdnyakov+ Full ATLAS simulation of Z0->m+m- in pp-,HI production is carried out. Point-like Z0 production is not influenced by QGP, so the study of jet quenching provided by Z0. One month HI running gives 5000 Z0 in the muon mode. The usage of this mode is helpful in study of jet quenching.Back-to-back configuration of Z0+jet event is tool for the jet reconstruction. ffbarag*/Z0 Z reconstruction

36. Quark-gluon structure functions The possibilities of measuring at the LHC thegluon distributionsin the proton bymeans ofsimultaneous registration of the direct photons (Z-bosons) and jets ("gamma/Z+jet" events) Investigation (within SANC) of possibility to apply an accurate Drell-Yan calculations for LHC luminosity monitoring and Parton-Distribution-Function measurements. • Development of a new generator for PDFs which obey QCD evolution equations at very low Feynman x and study of their influence on the cross sections of the basic LHC processes (by A.Kotikov, D. and V. Peshekhonov). PDF monitoring via D- orB-meson yields (Lykasov)?

37. Standard Model, Drell-Yan P.Starovoitov et al (Minsk) have considered two-photon mechanism of Drell-Yan lepton pair production in pp-collisions The two-photon contribution is not negligible!

38. Study of Drell-Yan processes in ATLAS • Precision calculations of the Drell-Yan process are carried out (SANC project) • From SM Lagrangian to event distributions • Including EW and QCD NLO corrections • Participating in the international group (Les Houche and TEV4LHC workshops • At the same time, the experimental study of the process is prepared usinig full ATLAS simulation/reconstruction • The results show that already with a decent LHC luminosity the cross-section can be measured with precision about 1% Reconstructed invariant mass of Z→μμ (1 year of LHC run)

39. Standard Model, applications

40. Some short-term plans • Top-quark Physics • Can be done rather quickly • Important test of SM (charge, mass, etc) • Background for SUSY, Exotics, etc • Energy calibrationvia Z,W and top, etc • Is the Top “the same” in all ”top” observables? • Heavy Ions Physics • QGP jet quenching via Z-jet events, γ-γ physics • Standard Model Physics • Parton DF verification in 2-jet events, B-mesons • Two-photon Drell-Yan processes • Gamma/Z-jet events and Gluon DF • W, Z – properties, etc

41. Some long-term plans • Higgs Physics • H→4μ, • H→bb, H→, H→Zγ, All other Higgs decay channels • SUSY Physics • How “the first observed” SUSY-particle shows itself in the other SUSY-channels? (Coherence) • SUSY is background for SUSY • Stop, Gluinos, Same-sign dileptons • Charged Higgs-boson • SUSY Dark MatterSearch with ATLAS, etc • Exotics Physics • SUSY R-hadrons (Travel ATLAS without decays) • SUSY long-living Staus, Stops, etc • Graviton (Spin=2) via Asymmetry_CE and via resonances • Monopoles, etc • Rare tau-lepton decays

42. Preparation for the ATLAS data analysis at JINR • Since January 2007 JINR site is successfully integrated in the ATLAS DDM (Distributed Data Management system) Training of use of distributed analysis tools (GANGA) is ongoing. Recent versions of ATLAS software are installed at JINR (11.0.41, 12.0.31, 12.0.6, 12.5.0) • 19.04.2007 the Tutorial on ATLAS Grid tools and distributed data analysis took place at JINR – the premier in Russian ATLAS Tier-2! Russian and JINR physicists participants of ATLAS experiment train and practise with Grid and the GANGA

43. Conclusions • We have enough attractive ideas in the ATLAS research program. • Some of above proposals (Higgs, Top) have already passed experimental procedure of simulations, background estimates and reconstructions in the ATLAS. With these tools we are ready to meet the first real data from the LHC. • Have ATLAS software installed at JINR • Have GRID and have participated in the Data Generation • Have clear short- and long-term plans • Have contacts with Russian ATLAS community • Have fruitfully working JINR-ATLAS-Physics Workshops and still invite the other Dubna-LHC groups (CMS, ALICE) to join us. Despite of some differences (detector particularities and software used) we all could get a lot of benefit from mutual discussions. • My urgent goals: DATA access,ATLAS soft at JINR, Early Physics