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Oleg Samoylov (DLNP) @ 111th Scientific Council, Feb. 16, 2012

Precise measurement of Charm Dimuon production cross-section in νN interactions and its various applications. Oleg Samoylov (DLNP) @ 111th Scientific Council, Feb. 16, 2012. Motivation of the Charm Dimuons. Charge current (CC). Neutral current (NC). q u ( ν ). q d (ℓ). f. f'. g.

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Oleg Samoylov (DLNP) @ 111th Scientific Council, Feb. 16, 2012

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  1. Precise measurement of Charm Dimuonproduction cross-section in νN interactionsand its various applications Oleg Samoylov (DLNP) @ 111th Scientific Council, Feb. 16, 2012

  2. Motivation of the Charm Dimuons Charge current (CC) Neutral current (NC) qu (ν) qd (ℓ) f f' g g / Cos θW W+ Z0 g = e / Sin θW Electro-weak interections in Standard Model (SM) NuTeV analysis Sin2θW = 1 − MW2/MZ2 = 0.2277 ± 0.0013 (stat.) ± 0.0009 (syst.) Rν = σνNC / σνCC = 0.3916 ± 0.0013 (SM 0.3950) Rν = σνNC / σνCC = 0.4050 ± 0.0027 (SM 0.4066) Charm dimuons in NOMAD

  3. Motivation of the Charm Dimuons NuTeV Roberto Petti for the NOMAD Charm dimuons in NOMAD

  4. A direct probe of the Strange sea Proton structure is defined by Parton Distribution Functions (PDF’s) of quarks q(x) and gluons g(x) νµN → µ−µ+X νµs → µ−c → µ−µ+X Charm dimuons in NOMAD

  5. Available charm dimuon data νµN → µ−µ+X⇒νµs →µ−c → µ−µ+X • Strange sea PDF s(x) based on approx. 10 000 events only Charm dimuons in NOMAD

  6. Neutrino induced charm dimuons • ν-induced charm dimuon production Dc = Σfh Dch, Bμ = Σfh B (h →μ+ X), h = D0, D+, Ds+, Λ+ • Charm production in (anti)neutrino DIS provides a clean and direct access to s(x) |Vcs|2=0.95 |Vcs|2=0.05 Charm dimuons in NOMAD

  7. NOMAD experiment at CERN SPS 1995-1998 Front Calorimeter (FCAL) Muon neutrino beam NOMAD logo Short baseline νμ→ντ oscillation experiment (620m) NIM A 515 (2003) 800-828 1. Largest samples of neutrino interactions currently available: - 20 M events with Iron in Front Calorimeter (50 k dimuons) - 2.5 M events with Carbon in Drift Chambers 2. Resolution for the vertexes: in Drift Chambers 0.1 ÷ 0.25 cm and in Front Calorimeter 0.6 ÷ 1.0 cm 3. Excellent reconstruction quality of individual (charged) tracks ∆p/p=3.5%, ε=95% 4. Good calorimetry: for ECAL ∆E/E=3.2%/E[GeV], for FCAL and HCAL ∆E/E=104%/E[GeV] Drift Chambers (DCH) NIM A 404 (1998) 96-128 Charm dimuons in NOMAD

  8. Reconstruction of the dimuon events Eν = Eµ− + Eµ+ + Ehad Event information Eν=81.4 GeV Eµ−=32.6 GeV Eµ+=19.0 GeV Mµµ=0.945 GeV Q2=3.26 GeV2 W2=89.4 GeV2 Background Charm dimuon Charm dimuon exp. DATA and Bg. subtraction: Charm dimuons in NOMAD

  9. Relevance of the NOMAD dimuon data νµN → µ−µ+X⇒νµs →µ−c → µ−µ+X • The NOMAD has the largest sample of ν-induced charm dimuons • The neutrino energies closest to the charm production threshold Charm dimuons in NOMAD

  10. Charm dimuon X-section measurement • Measure RATIO of cross-sections to reduce systematics Rµµ ≡ σµµ /σcc ≃ Nµµ /Ncc (x); x = Eν , xBj , √s • Require leadingµ− and Q2 ≥ 1 GeV2 ∫ σµµ φ dx dy dEν =5.15 ± 0.05 × 10−3 νµ CC • Total systematic uncertainty (17 differentsources) ~ 2% • Agreement with model calculationbased upon global PDF fitwith NuTeV+CCFRdimuon data only Charm dimuons in NOMAD

  11. Sensitivity to the Strange sea • Add NOMAD σµµ /σcc to global PDF fit with NuTeV and CCFR dimuon data S. Alekhin, R.Petti • Consistency of central values • Reduction of s(x) uncertainty by a factor 2 down to 3% Charm dimuons in NOMAD

  12. Charm quark mass and strange sea supression factor Strange sea and c-quark parameters Charm dimuons in NOMAD

  13. Strange sea and c-quark parameters • Charm fragmentation D(z, ε) in Collins-Spiller parametrization • Semileptonic branching ratio Bµ(Eν) = a/(1 + b/Eν) Charm dimuons in NOMAD

  14. Quark fragmentation measurement Scheme Fπ=(Fee±, Fℓp+,Fℓn+,Fℓp-,Fℓn-, Fνp+,Fνn+,Fνp-,Fνn-,Fνp+,Fνn+,Fνp-,Fνn-) Dπ = (Dd+,Du+,Ds+,Dc+, Mp,d+,Mp,d-,Mp,u+,Mp,u-,Mp,d+,Mp,d-,Mp,u+,Mp,u-,Mp,s-) F, E, D ( z,pT ; { s | x,Q2 } ) F = ED ⇒ D = E-1F NOMAD Durham HepData http://hepdata.cedar.ac.uk/ (more than 100 experimental DATA) This work in progress Charm dimuons in NOMAD

  15. Current JINR activity at CERN • More precise knowledge of the Strange sea of the Nucleon allows to make more accurate prediction of strange particles production in pp collisions (ATLAS, CMS, ALICE) • Measurement of fragmentation functions Dq and Mp,q provides better estimation of spin transfer from quark to produced particles (COMPASS) • Improvement of neutrino-induced charm dimuon production can reduce uncertainty of charm background prediction for νμ→ντ oscillation experiments approx. by a factor 2 (OPERA) Charm dimuons in NOMAD

  16. Muon neutrino from Atmospheric charm The Baikal experiment is interesting in prediction for cross-sections of charm particle production in atmospheric nuclear cascade with generation of the muonic neutrino. In collaboration with N.Budnev and S.Sinegovsky from ISU and API (Irkutsk) we plan to calculate neutrino flux prediction for different zenith angles using parameterization of the spectrum of primary cosmic rays in wide energy interval (including ``knee'' region). Charm dimuons in NOMAD

  17. Publications in 2011 and Acknowledgements • O.Samoylov, R.Petti, PEPAN Lett., 2011, Vol.8, №7 (170) Pp.1252-1261 • A.Edemskaya, D.Naumov, O.Samoylov, PEPAN Lett., 2011, Vol.8, №7 (170) Pp.1276-1281 • O.Samoylov, Proceedings of the PANIC-11 conf., 2011, MIT (Cambridge, USA) • O.Samoylov, Proceedings of the AYSS’11 conf., 2011, JINR (Dubna, Russia) Pp.114 Work has been done in collaboration with R.Petti (USC) and D.Naumov (JINR), with participation of M.Gonchar (JINR), A.Edemskaya (ISU), S.Starikova (ISU). We are grateful to V.Cavasinni, L.Camilleri, L.DiLella for stimulating discussions of this work. This work is partially supported by JINR grant, CERN, RFBR grant, Russian Federal Targeted Program “Research and Research-Human Resources for Innovating Russia”. Charm dimuons in NOMAD

  18. Nuclear effects (incoming analysis) BEBC Coll., ZPC 36 (1987) 337; PLB 232 (1989) 417. • Nuclear corrections are crucial in order to use ν(ν) data in global QCD fits since all existing data on heavy targets • Only direct measurement of nuclear effects in ν(ν) SFs from ratio 20Ne/D in BEBC • Our measurements of d2σ/dxdy cross-section on Carbon and Iron R.Petti, M.Gonchar, O.Samoylov Charm dimuons in NOMAD

  19. Precise measurement of Charm Dimuonproduction cross-section in νN interactionsand its various applications Oleg Samoylov (DLNP) @ 111th Scientific Council, Feb. 16, 2012

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