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ẽ R , μ̃ R, ẽ L Analysis Status

ẽ R , μ̃ R, ẽ L Analysis Status. Outline Goal Cross sections and Luminosity assumptions Event Selection Method, dN / dP and Δ P/P ² e¯ momentum measurement problem ? Fit Method Preliminary Results Summary J- J.Blaising , J.Nardulli. ẽ R , μ̃ R, ẽ L Analysis Goal.

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ẽ R , μ̃ R, ẽ L Analysis Status

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  1. ẽR,μ̃R,ẽL Analysis Status Outline • Goal • Cross sections and Luminosity assumptions • Event Selection Method, dN/dP and ΔP/P² • e¯ momentum measurement problem ? • Fit Method • Preliminary Results • Summary J-J.Blaising, J.Nardulli LCD WG6 meeting

  2. ẽR,μ̃R,ẽL Analysis Goal Assess the physics performances, statistical accuracy reachable for: • ẽR , μ̃R and μ̃Lproduction cross sections • ẽR , μ̃R , μ̃L, χ̃⁰₁ and χ̃⁰₂ masses • Establish the ẽ and μ̃helicity LCD WG6 meeting

  3. S and B Cross Sections, Luminosity Integrated luminosity assumptions: ẽR :-> e + χ̃⁰₁: 250 fb¯¹ (~ 0.5 year -> 1500 events ) μ̃R :-> μ + χ̃⁰₁ :2000 fb¯¹ (~ 4 years -> 1400 events) ẽL: -> e + χ̃⁰₂ ; χ̃⁰₂ -> h⁰/z⁰ + χ̃⁰₁ : 4000 fb¯¹ (~ 8 years -> 1000 events ) Work started LCD WG6 meeting

  4. Event selection TMVA is used to build PDF (S, B) out of input histograms (Evis, PT12,...) and combine them into a total probability classifier. Half of data sample is used to compute the PDF ; the second half is the data sample. The classifier ranks events to be S/B like; it is used to select the events. LCD WG6 meeting

  5. dN/dP (S) for Different Selection CutsC0=-1, C1=-0.8, …, C4=-0.2 μ̃ (left); the selection cut affects more the lower edge of the distribution. ẽ(right); the cut affects also the high P; it is likely due to ΔE/E² which is worse for electrons (next slide). LCD WG6 meeting

  6. dN/dPv (μ̃, ẽ) No γγ->h Overlay Two gaussians fit to take into account the tails : Int[G1]/Int[G2]=5.0 % for μ± (left) ; 20% for e± (right). More Brems in ẽ; is ΔP/P²right? Check using events without: FSR γ (gs=1), Bremssγ (gs=0) LCD WG6 meeting

  7. ΔP/P² (ẽ and eGun data without γ) ΔP/P²: ẽ (left), tail and 10% overflow ΔP/P²: Jacopo’s eGun events, tail and 12% overflow ΔP/P² should be similar as for μ !! ; checked that P.pfo=P.track Problemin e track measurement ? Unlikely LCD WG6 meeting

  8. ΔP eGun data without γ ΔP (P.Pfo-EemCluster) vsΣPγPfo In 3500 events without γ Pandora finds 4600 photons Bug in McParticleSkimmed ? LCD WG6 meeting

  9. ẽ̃ event without γ Pandora RPFO 0 id -11 E 624.24 theta 146.12 phi -130.48 RPFO 1 id 2112 E 13.65 theta 145.75 phi -129.63 RPFO 2 id 22 E 9.21 theta 145.69 phi -131.14 RPFO 3 id 22 E 508.49 theta 36.23 phi -14.46 RPFO 4 id 11 E 425.11 theta 35.55 phi -14.52 (P.Trk=425.11) McParticleSkimmed TMGO 0 id -11 E 624.27 theta 146.12 phi -130.48 e- or e+ TMGO 1 id 11 E 836.46 theta 35.55 phi -14.49 e- or e+ MPFO 0 id -11 E 624.24 theta 146.12 phi -130.48 theta+ID match: -11 /-11 dE 8.69e-08 MPFO 1 id 11 E 933.60 theta 35.55 phi -14.49 theta+ID match: 11 /11 dE 1.39e-04 Why is there a γ of 504GeV in Pfo and not in McParticleSkimmed A dump of the events shows that there is a γ of 423 Gev in McParticle which is not Put in McParticleSkimmed Where is the problem ? LCD WG6 meeting

  10. dN/dPv (μ̃, ẽ) with γγ->h overlay The γγ-> h overlay does not degrade the μ and e energy resolution. One can consider that the discriminating variables and the event selection are not affected by the γγ-> h background. LCD WG6 meeting

  11. dN/dP, S(μ̃) +B; Cuts C0 and C4 LCD WG6 meeting

  12. dN/dP S(ẽ) + B; Cuts C0 and C4 LCD WG6 meeting

  13. dN/dP Fit The end points EL and EH of the μ/e momentun distribution are given by (1). The μ̃/ẽ and χ⁰ masses are determined from a 2 parameters fit to the reconstructed momentum spectrum,dN/dP; S+B–B(MC). For a set of masses, a template spectrum of N events is modeled accordingto (1), N=Ndata. For each event √S is thrown taking into account ISR +Beamstrahlung spectrum. The momentum is smeared usingΔE/E². The chi2 = Σ(data-template)²/err² is computed. Minuit is used to iterate until the chi2 is minimized. LCD WG6 meeting

  14. μ: Fit dN/dP S+B-B(MC) Fit S only (left), S+B-B(MC) (right) Δ m/m (μ̃R) ~ 0.5 % ; Δ m/m ( χ̃⁰₁) ~ 2% LCD WG6 meeting

  15. ẽ: Fit dN/dP S only, S+B-B(MC) For S only (left); S+B-B(MC) (right) Δ m/m (ẽR) ~ 0.6 % ; Δ m/m ( χ̃⁰₁) ~ 3% LCD WG6 meeting

  16. Polarization Polarized beams will allow to study the cross section variation in order to determine the ẽ and μ̃helicity: With B1 (e¯) L:0.2/R:0.8 and B2 (e⁺) L:0.0/R:0.0 the μ̃ and ẽ cross sections are about 30% larger. The major backgrounds are unchanged LCD WG6 meeting

  17. Summary • The γγ-> h overlay does not degrade the μ and e energy resolution. One can consider that the discrimination variables and the event selection are not affected by the γγ-> h background. No need to overlay the SM background. • With 250 fb¯¹ for ẽR and 2000 fb¯¹ for μ̃R , theproduction cross • sections can be determined with a relative statistical uncertainty • of ~ 3% . • The mẽR , mμ̃R can be measured with a relative statistical accuracy • of~ 0.5 % and ~ 2 % for χ̃⁰₁ . • Polarized beams will allow to establish the ẽ and μ̃helicity for the • measured masses . • Work started to assess the performance for the ẽL. • Fix e bremsstrahlung problem required LCD WG6 meeting

  18. Spare Slides LCD WG6 meeting

  19. dN/dP (S+B) for C4 LCD WG6 meeting

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