HES-HKS & KaoS meeting Toshiyuki Gogami 18Dec2013

Missing mass Resolution Intrinsic mass resolution Production point displacement from the matrix origin Mass offset due to energy loss in target

Intrinsic mass resolution  Energy straggling, raster and mass offset are not included in these estimation  Total resolution cannot be a simple quadratic sum since variables are not independent (but, simple quadratic sum is shown as an intrinsic resolution here) (but, simple quadratic sum is shown as an intrinsic resolution here)

Production point displacement from the matrix origin (z-direction) 1.Effects are smaller (<0.1 MeV/c 2 ) for other targets since their thickness are less than 0.05 cm. 2.These effects are implicitly absorbed by matrices in a process of tuning (already checked in blind analysis)

Energy loss correction (Before talking about mass offset) Target Most probable value for each particle  Energy loss correction value Production at the center of target e e’ K+K+

Energy loss correction (Before talking about mass offset) Target Most probable value for each particle  Energy loss correction value Production at the center of target e e’ K+K+

Mass offset due to energy loss ~ 0.7 MeV (hand calc MeV) z Most probable values Target

In the case of 7 Λ He Others = 1.4 – 0.58 = 0.82 [ MeV ] Offset: 0.7 MeV, intrinsic: 0.4 MeV Sqrt(0.7* *0.4) = 0.8 Matrix Matrix + MM offset + others

Achievable resolution Simply subtracted matrix z dependence

Blind analysis The first results

Flow chart of blind analysis Compare Blind

Flow chart of blind analysis 1.Imitation data generation 2.Distorted matrix generation 3.Tuning 4.Comparison tuned results with generated data

The first sample Tune with Λ and Σ0 with realistic B.G. shape

Missing mass Restarted tuning…. With new energy loss corrections for 12 C target  87.5 mg/cm 2 (ELOG)

Carbon target 700 keV (FWHM)

Lithium target 1000 keV (FWHM)

720 keV (FWHM)

Summary Resolution estimation Estimation will be improved soon Blind analysis The first results (delta B Λ < 100 keV) Matrix tuning restarted

Backup

Li target

Target [mg/cm 2 ] Intrinsic (page 4) + Δm offset [MeV/c 2 ] Monte Carlo – (matrix z dep.) ΛCH Λ He 7 Li Λ Be 10 B Λ B 12 C Λ V 52 Cr

Production point displacement from the matrix origin (x-direction) x includes information of z because the target is tilted  A pure effect from the x-dependence is compensated by the z-dependence Target z x

Production point displacement from the matrix origin (y-direction) y-dependence

Energy loss correction (Before talking about mass offset) Target Most probable value for each particle  Energy loss correction value Production at the center of target e e’ K+K+

Spectrometer resolution

Mass offset where A, B and C are defined in page 4. Simply calculated by z Most probable values Target

Mass offset where A, B and C are defined in page 4. Simply calculated by z Most probable values Target

Want to understand simulated results (resolution)

Energy loss correlation Bug fixed in POSI  Expected correlation can be seen now.