1 / 20

Status of KLOE real data analysis by the AMADEUS group

Status of KLOE real data analysis by the AMADEUS group. Oton Vázquez Doce, 4 Maggio 2007. Our firsts steps were with Monte Carlo. Production of dedicated KLOE Monte Carlo ntuples Estimation of fraction of K - stopped in the Drift Chambers volume of KLOE setup. Nuclear Interactions: K - + N.

jui
Télécharger la présentation

Status of KLOE real data analysis by the AMADEUS group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Status of KLOE real data analysis by the AMADEUS group Oton Vázquez Doce, 4 Maggio 2007

  2. Our firsts steps were withMonte Carlo... • Production of dedicated KLOE Monte Carlontuples • Estimation of fraction of K- stopped in the Drift Chambers volume of KLOE setup

  3. Nuclear Interactions: K- + N K- “stopped” Monte Carlo 0.1% stopped inside the DC's | z | < 140 cm 40 < ρ < 150 cm ρ vs z (cm)

  4. Since begginning of 2007 • February 2007 accepted to use 2005 data up to a luminosity equivalent to the 2001/2002 year (400 pb-1) • Production of KLOE real data ntuples with tag mechanisms 2BODY + DE/DX (50 pb-1 up to now) • Start analysis tunning strategy

  5. Strategy of search K- + 4He -> n + (K-ppn) n ~ 510 MeV/c K- + 4He -> p + (K-pnn) p ~ 550 MeV/c

  6. Signature for ppnK- Decay 4He + K- ppnK- + n • Many channels with Λ can be identified by their decay products: p+π- or n+π0 • Classical hadronic interactions of K- in 4He producing also Λ (69%) • P. A. Katz, et.al., Reactions of stopping K- in Helium, Phys. Rev. D1, 1267-1276, (1970) decay:  + p + n p + - n n - - p p

  7. Λp+π- search criteria: • Vertex made of two opposite charge particles inside the Drift Chamber volume • For the negative track (π-) require energy deposit in the DC wires < 95 ADC counts • For the positive track (proton) start looking for an associated cluster to in the extrapolation of the track to the calorimeter region

  8. Protons identification • Implementation of cuts to remove K- 3 body decay background ( K-π-π-π+) E (MeV) charge * p (MeV/c)

  9. Protons identification • Implementation of cuts to remove K- 3 body decay background ( K-π-π-π+) E (MeV) Lambda inv. Mass (Mev/c2) Lambda p (Mev/c) pion p (MeV/c) proton p (MeV/c) charge * p (MeV/c)

  10. Protons identification (low energy) • If no cluster associated, require: • last DC measurement for the track compatible with the particle reaching the calorimeter • Proton signature in the ADC values of DC wires ADC counts p (MeV/c)

  11. Protons identification (low energy) • If no cluster associated, require: • last DC measurement for the track compatible with the particle reaching the calorimeter • Proton signature in the ADC values of DC wires ADC counts p (MeV/c)

  12. Final Selection: pions protons ADC ADC p (MeV/c) p (MeV/c) ADC p (MeV/c) ADC p (MeV/c)

  13. Final Selection: Λ invariant Mass (MeV/c2) σ~0.5 MeV/c2 θ (deg) proton-pion pΛ (MeV/c) Mpπ(MeV/c2)

  14. Final Selection: Λ invariant Mass (MeV/c2) Cut in momentum in the Λ c.m.s. 91 < pp,π- < 111 (MeV/c) θ (deg) proton-pion pΛ (MeV/c)

  15. Final Selection: Λ invariant Mass (MeV/c2) Cut in Λ invariant mass 1114 < MΛ< 1115 (MeV/c) θ (deg) proton-pion pΛ (MeV/c)

  16. Λ vertices Interactions in the DC entrance wall (Carbon) 8500 events Interactions in 4He 1500 events ρ vs Z (cm) x vs y (cm) search for Σ(1385)  Λπ ρ (cm) ρ (cm) Z (cm)

  17. Search for Λ “partners” • Particles in the same vertex of the p and π- p (MeV/c)

  18. Search for Λ “partners” ADC • Particles “near” to the Λ vertex # negative tracks # positive tracks π p ADC ? Λ charge * p (MeV/c) charge * p (MeV/c)

  19. Search for Λ “partners” ADC • Particles “near” to the Λ vertex # negative tracks # positive tracks π p Invariant mass Λ d (MeV/c2) ADC ? Λ charge * p (MeV/c) angle Λ d (deg) charge * p (MeV/c)

  20. Next steps... • Additional checks on Λ (low momentum, vertex reconstruction, efficiencies...) • Increase statistics • Study the underlying physics of Λ (formation mechanism, deeply bound?) • Search for Λ n+π0 (started) • Strategy for neutral particle search

More Related