SPIN 2012, Dubna, September 17-22, 2012 I.G. Alekseev a,* , V.A. Andreev b , I.G. Bordyuzhin a , D.A. Fedin a , Ye.A. Filimonov b , V.V. Golubev b , A.B. Gridnev b , E.A. Konovalova b , L.I. Koroleva a , N.G. Kozlenko b , V.S. Kozlov b , A.G. Krivshich b , B.V. Morozov a , V.M. Nesterov a , D.V. Novinsky b , V.V. Ryltsov a , M. Sadler c , A.D. Sulimov a , V.V. Sumachev b , D.N. Svirida a , V.I. Tarakanov b , V.Yu. Trautman b a Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, Moscow, Russia. b Petersburg Nuclear Physics Institute, Gatchina, Leningrad district, Russia c Abilene Christian University, Abilene, Texas, USA * [email protected]High precision measurements of the pion-proton elastic scattering and kaon- lambda production in the EPECUR experiment
27
Embed
SPIN 2012, Dubna, September 17-22, 2012 I.G. Alekseev a,*, V.A. Andreev b, I.G. Bordyuzhin a, D.A. Fedin a, Ye.A. Filimonov b, V.V. Golubev b, A.B. Gridnev.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
V.V. Ryltsova, M. Sadlerc, A.D. Sulimova, V.V. Sumachevb, D.N. Sviridaa, V.I. Tarakanovb, V.Yu. Trautmanb
a Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, Moscow, Russia. b Petersburg Nuclear Physics Institute, Gatchina, Leningrad district, Russia
c Abilene Christian University, Abilene, Texas, USA* [email protected]
High precision measurements of the pion-
proton elastic scattering and kaon-lambda
production in the EPECUR experiment
Pentaquark antidecuplet
2
?
Original prediction – N***(1710)From modified PWA – 1680 or 17301
1) R. Arndt et al., Phys.Rev. C69 (2004) 035208SPIN’2012
Igor Alekseev (ITEP, Moscow)
N(1685)
3
NNR’2009, Edinburg, June 8-10, 2009 http://2009physicsevents.org
η-photoproduction off neutron
GRAAL:
SPIN’2012
Igor Alekseev (ITEP, Moscow)
SPIN’2012
4Igor Alekseev (ITEP, Moscow)
M.J Amaryan et al. Phys.Rev. C85 (2012) 035209
MC
MCcor
The same CLAS statistics of 2004 (g11a run period) as in R. De Vita et al., [CLAS Collaboration], Phys. Rev. D74, 032001 (2006) A narrow structure at KS missing mass MX(KS) = 1.543 GeV with a Gaussian width = 0.006 GeV for the reaction γp→pKSKL
when M(KSKL) = mϕ and −tΘ<0.45 GeV2 with 5.4σ statistical significance.
S+MCcor
S. Naohito @ SPIN 2010
6Igor Alekseev (ITEP, Moscow)
Resonance parameters within safe reach by the experiment:
This provides a good coverage of both theoretical and experimental expectations.
• “Formation” – type experiment.• Extremely high invariant mass resolution (~0.6 MeV), provided by high momentum resolution of the magneto-optic channel 0.1%.• High statistical precision: 0.5% for elastic scattering and 1% for K-production.• Magnetless spectrometer with drift chambers.• Liquid hydrogen target.• Very small amount of matter on the particle paths.
EPECUR:
Not narrow resonances only …• Precise cross section measurements:p p: d/d – 0.5% statistical precision and 1 MeV momentum stepp K0: REAC – 1% statistical precision and the same step
Very important data for PWA• “Usual” resonace P11 N(1710)***• -polarization in the reaction p K0 - an order of magnitude better precision then the best data available now - NIMROD (78)
SPIN’2012
Setup for elastic scattering
7Igor Alekseev (ITEP, Moscow)
Proportional chambers with 1mm pitch and 40 um aluminum foil potential electrode in the first focus (1FCH1-4) and in front of the target (2FCH1-4). Momentum of each incident pion is tagged with the precision better 0.1%. Liquid hydrogen target with beryllium outer shell and mylar hydrogen container. The target diameter is 40 mm and the length along the beam ~250 mm. 8 modules of drift chambers with hexagonal structure to measure tracks of particles produced. Trigger scintillation counters S1, S2, A1. NMR system for measurement field in the magneto-optic channel dipoles with precision better 0.1%. Triggers:
Some irregularity is seen in the region of the most interest (1020-1040 MeV) in several θCM bins
Only one half of the statistics in this region was already analyzed
We plan to get more statistics in the narrow energy range
SPIN’2012
20Igor Alekseev (ITEP, Moscow)
Statistical errors only
SPIN’2012
21Igor Alekseev (ITEP, Moscow)
Statistical errors only
SPIN’2012
22Igor Alekseev (ITEP, Moscow)
Statistical errors only
SPIN’2012
23Igor Alekseev (ITEP, Moscow)
Statistical errors only
SPIN’2012
24Igor Alekseev (ITEP, Moscow)
Statistical errors only
–pK0S +––p
We keep the target and the beam equipment
The drift chambers we already have
New wide-aperture drift chambers
New hodoscopes
Most of the events have either all 4 particles going forward or 3 particles including the proton going forward and one pion going in some other direction
SPIN’2012
25Igor Alekseev (ITEP, Moscow)
26Igor Alekseev (ITEP, Moscow)
The new wide-apperture drift chamber tests at PNPI
SPIN’2012
Status and plans
27Igor Alekseev (ITEP, Moscow)
Elastic scattering Detector EPECUR for precision measurement of elastic πp-scattering was built and comissioned:
track efficiency in the drift chambers > 99% beam momentum tagging is better 0.1%
We took 4 physics runs and 2.97 billions of triggers are collected. The analysis is under way. The preliminary results show some irregularity at Pbeam=1020-1040 MeV/c. We plan to take more data in the narrow region of interest as well as extend the measurement till 2 GeV/c The beam composition will be determined using Cherenkov counter and Monte-Carlo simulations
K0Λ-production The first out of 4 required wide-aperture drift chambers is manufactured and is being tested at PNPI We have full front-end and DAQ electronic Engineering of mechanical structure as well as of TOF forward hodoscope is under way.