1 / 9

Attempt to solve alignment problem with E/p ratio

Attempt to solve alignment problem with E/p ratio. (very preliminary) 04.11.2003 Weekly meeting. Motivation (1). An alternative way to find time dependent term for momentum correction (misalignment variation in time) using LKr . For e + and e - we compare E (measured by LKr) with

nova
Download Presentation

Attempt to solve alignment problem with E/p ratio

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. Attempt to solve alignment problem with E/p ratio (very preliminary) 04.11.2003 Weekly meeting

  2. Motivation (1) • An alternative way to find time dependent term for momentum correction (misalignment variation in time) using LKr. • For e+ and e- we compare E (measured by LKr) with P (measured by spectrometer).

  3. Motivation (2) • Momentum distortions: Preal = Pobservable + dPM + dPAC +dPAT(t) where: dPM – magnetic field correction dPAC – constant misalignment correction dPAT(t) – time dependent misalignment correction • Energy measured by LKr: Ereal = Eobservable + dE , where the corrections dE is expected to be time independent. • The correction dPATwill be connected with E/p ratio: dPAT(t) + dPconst= E – P = P (E/P – 1).

  4. Selection (1) • We need “pure” electrons and positrons coming from: K  pp0D • Selection: • 3 tracks coming from 1 vertex • Only 1 vertex • Time window 40 ns • DTrack time < 10 ns • 1 unassociated cluster in LKr with E>2 GeV • Zvertex < 8500 cm • RCOG < 2 cm • No E/p conditions for e+, e- and p. • In case of three tracks we have two possible mass solutions for a given charge of the kaon (we know what exactly is the “odd” particle and the “even” particles can swap their masses). We take the combination, which mass is more close to the PDG value of the kaon mass. • To exclude additional background, we remove events with mee<0,01 GeV.

  5. Selection (2) |M-MPDG|<0,01 Mass spectra E/p spectra

  6. E/p for supersample I e+(K+) e-(K+) e+(K+) e-(K+) e+(K-) e-(K-) e+(K-) e-(K-) Without dPM correction… With dPMcorrection (B corrected to put <M+3p + M-3p>/2=MPDG)

  7. E-p for supersample I e+(K+) e-(K+) e+(K+) e-(K+) e+(K-) e-(K-) e+(K-) e-(K-) Without dPM correction… With dPMcorrection.

  8. E/p and E-p for supersample II e+(K+) e-(K+) e+(K+) e-(K+) e+(K-) e-(K-) e+(K-) e-(K-) E/pE-p

  9. To do… • Check the correction on B field. • Corrections dependencies of (X,Y)DCH, P e.t.c. • Apply the obtained corrections to pions from K3p and check the mass split. • Check another source of electrons and positrons.

More Related