1 / 1

Experimental Setup – Simultaneous K+/K- beams

Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN Anne Dabrowski (work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN)

kaori
Download Presentation

Experimental Setup – Simultaneous K+/K- beams

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. Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN Anne Dabrowski (work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN) Northwestern University, Evanston, Il B+ magnet TAX 17 TAX 18 FDFD K+ K+ focusing beams K- K- DFDF Quadrupole 2nd Quadruplet ACHROMAT 10 cm vacuum tank He tank + spectrometer FRONT-END ACHROMAT 1cm not to scale Vus x f+(0) 200 250 m 50 100 beams coincide within <1mm 114m decay volume Data sample from a special low intensity run 2003 NA48/2 Detector Experimental Setup – Simultaneous K+/K- beams Data Sample: • 8 h K+/K- with min bias trigger ... no cut at trigger level on Dalitz plot, & εtrig ~ 99.8% Ke3 Br measurement: • Normalize Ke3 events to π ±π0 events • Br(π ±π0) = 0.2113±0.0014 • Selected Events: • Ke3+ ..... 59k Ke3- ..... 33k • π ±π0 ..... 468k π ±π0 ..... 260k • Main detector components • Magnet spectrometer • Two drift chambers before and two after spectrometer magnet • Momentum resolution < 1% for 20 GeV/c momentum • Anti-counters • Liquid Krypton Calorimeter  • Hadron Calorimeter • Muon Veto system • Beams K± Vusfrom Ke3 Status of Vus from Km3data Data/MC Comparison for Br( Km3) measurement Muon ID efficiency using muonsfrom K±→μ±ν • Similar Analysis, Normalize Km3 to π ±π0 • Particle ID … 2 Methods for muon ID • Using the Muon Veto for Muon ID (global 99.92% efficient) • Using the Electromagnetic and Hadronic calorimeters for 1-MIP signal (max 98.% efficient, but momentum dependent) • Number of events: • μ+π0ν (μ-π0ν ) 60 k (33 k) – Statistical error comparable to Ke3 Mom. of Track Energy π0 Data/MC looks good! Br(Km3) available soon!! CKM matrix – Unitary Problem? Patera New Determinations of Vus Inputs into extracting Vus from Ke3 • Unitarity of CKM matrix requires: |Vud|2 +|Vus|2+ |Vub|2 = 1 • PDG 2004 data: |Vud| = 0.9738 ± 0.0005 - well measured |Vub| = (3.67 ± 0.47).10-3 - ( |Vub|2 ≈ 10-5 negligible) • SM prediction |Vus| = 0.2274 ± 0.0021 • Experimental value (begining 2003) |Vus| = 0.2200 ± 0.0026  |Vus|= 0.0074 ± 0.0033 ~2.2  discrepancy • 1 % Measurement needed • (limited by theory) New Preliminary NA48/2 Br(Ke3) Data/MC Comparison for Br(Ke3) measurement Br(Ke3) = (5.14 ± 0.02 stat± 0.06 syst)% pipi0 Ke3 Mom. of Track Energy π0 Mom. of Track Energy π0 Data/MC Data/MC Data/MC Data/MC Radiative correction in Measurement of Br(Ke3) Ginsberg Implementation OK in MC generated events – see paper (Ginsberg Phys Rev vol 162 Num 5 25 October 1967) Data/MC, radiative corrections on Data/MC, radiative corrections off

More Related