Memo for S-2S simulation Toshi Gogami 2014/7/25

Contents Missing mass resolutions with S-2S / SKS.

Flow of Monte Carlo simulation POSI2 gen Process Geant4 Analysis K - energy loss (K -,K + ) kinematics K + energy loss Missing mass reconstruction Momentum resolution Angular resolution Vertex resolution

Particle generation K - momentum: 1800 MeV/c K + momentum: Uniform 1270 – 1470 GeV/c K + angle: Spherical uniform 0.0 – 0.26 rad Assumed Ξ’s binding energy: 7 Ξ H: 0.0 MeV 10 Ξ Li: 0.0 MeV 12 Ξ Be: 4.5 MeV Fig: Particle distributions in the simulation

Each term contribution to the missing mass resolution Missing mass, M H (Missing mass に対する各項の寄与 ) Calculated event by event  Mean values will be shown in results.

Assumptions K - momentum resolution, Δp 1 /p 1 = 1.0E-3 K + momentum resolutions, Δp 2 /p 2 S-2S: 5.0E-4 SKS: 2.0E-3 Angular resolution, Δθ = 2 mrad Gaussian function FWHM

Examples ( with S-2S, 9.3 g/cm 2 CH 2 ) Momentum resolution Target Momentum resolution Target Energy loss correction

Results of the simulation FWHM [MeV]Remarks Target [g/cm 2 ] - --CH 2 (4.65/9.30) Reactionp(K -,K + )Ξ 7 Li(K -,K + ) 7 Ξ H 10 LiB(K -,K + ) 10 Ξ Li 12 C(K -,K + ) 12 Ξ Be Intrinsic Resolution [MeV] p K Calculations for S-2S p K θKθK Total Quadratic sum Simulation w/o target (S-2S) Simulation w/o target (SKS) Simulation w/ target w/o correction (S-2S) / 3.7 Simulation w/ target w/o correction (SKS) / 3.7 Simulation w/ target w/ correction (S-2S) / 2.0 dE vs. MM rough linear correction Simulation w/ target w/ correction (SKS) / 3.3 dE vs. MM rough linear correction 質量数大  角度の寄与小 標的厚で違いなし  運動量分解能で制限されている

Summary S-2S + CH 2 ( 4.65/9.30 [g/cm 2 ] ) + energy loss correction: ΔM H = 2.0 MeV (FWHM) SKS + CH 2 ( 4.65/9.30 [g/cm 2 ] ) + energy loss correction: ΔM H = 3.3 MeV (FWHM) 12 C(K -,K + ) 12 Ξ Be

Backup

Missing mass vs. Energy loss in the target (9.3 g/cm 2 CH 2 ) Energy Losses of K - and K + [MeV] Energy Losses of K - and K + [MeV] Fitting with a linear function (test) Before correction After correction [Counts / 0.4 MeV] -B Ξ + 4.5[MeV] SIMULATIONSIMULATION SIMULATION SIMULATION

Missing mass vs. Energy loss in the target (4.65 g/cm 2 CH 2 ) Energy Losses of K - and K + [MeV] Energy Losses of K - and K + [MeV] Fitting with a linear function (test) Before correction After correction [Counts / 0.4 MeV] -B Ξ + 4.5[MeV] SIMULATIONSIMULATION SIMULATION SIMULATION

-B Ξ vs. z 係数の差が起因？

z vs. θ K Z が小さい程ボケる ( 多重散乱の効果 )

z vs. dE Z が小さい大きい ( 多重散乱の効果で path length が伸びる )

-B Ξ vs. dE ランダウ分布の尾

ミッシングマスに対する各項の寄 与 p: p_{K-}: * * p_{K-} = MeV p_{K+}: * * p_{K+} = MeV theta_{K}: * = MeV mt/mh= Li7: p_{K-}: * * p_{K-} = MeV p_{K+}: * * p_{K+} = MeV theta_{K}: * = MeV mt/mh= B10: p_{K-}: * * p_{K-} = MeV p_{K+}: * * p_{K+} = MeV theta_{K}: * = MeV mt/mh= C12: p_{K-}: * * p_{K-} = MeV p_{K+}: * * p_{K+} = MeV theta_{K}: * = MeV mt/mh= hyperdragon3: /home/dragon/POSI2/analysis/root/mmreso_contribution/ Toshi Gogami, 24July2014 After bug fixed in the calculations.

Pedestals for Cerenkov detector