V. A. Sakharov

Measurement of the spin rotation parameter A+ in the elastic scattering of positive pions on a longitudinally-polarized proton target in the second resonance region

Abstract The ITEP-PNPI collaboration presents the first results of the spin rotation parameter A+ measurements in the second resonance region. The experiment was performed at the ITEP accelerator at a positive pion beam momentum 1.43 GeV/c for scattering angles θcm = 127° and 133°. The setup was based on a polarized proton target and a carbon-plate polarimeter. The obtained data is compared with the predictions of the existing partial-wave analyses.

Search for the Cryptoexotic Member N10¯ of the Baryon Antidecuplet 1/2+ in the Reactions π−p→π−p and π−p→KΛ

The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the {pi}{sup -}p system invariant mass in the region (1610-1770) MeV with the detection of {pi}{sup -}p and K{lambda} decays. The scan is supposed to be done by the variation of the incident {pi}{sup -} momentum and its measurement with the accuracy of up to {+-}0.1%(better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto-optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at P{sub {pi}} = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the π−p system invariant mass in the region (1610–1770) MeV with the detection of π−p and KΛ decays. The scan is supposed to be done by the variation of the incident π− momentum and its measurement with the accuracy of up to ±0.1% (better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto‐optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at Pπ = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.

Search for the Cryptoexotic Member N{sub 10} of the Baryon Antidecuplet 1/2+ in the Reactions {pi}{sup -}p{yields}{pi}{sup -}p and {pi}{sup -}p{yields}K{lambda}

The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the {pi}{sup -}p system invariant mass in the region (1610-1770) MeV with the detection of {pi}{sup -}p and K{lambda} decays. The scan is supposed to be done by the variation of the incident {pi}{sup -} momentum and its measurement with the accuracy of up to {+-}0.1%(better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto-optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at P{sub {pi}} = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the π−p system invariant mass in the region (1610–1770) MeV with the detection of π−p and KΛ decays. The scan is supposed to be done by the variation of the incident π− momentum and its measurement with the accuracy of up to ±0.1% (better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto‐optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at Pπ = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.

Λ‐Polarization Measurement in π−p→K0Λ in the Framework of ‘EPECUR’ Experiment Proposal

The idea of ‘EPECUR’ was inspired by the recent splash of the activity around the pentaquark matters. The goal of the experiment is the search for narrow resonant states in the reactions π−p → π−p and π−p → K0Λ based on the very precise cross section measurements in fine energy steps of 0.5 MeV in terms of the invariant mass. As a valuable byproduct of the second stage of the experiment, Λ‐polarization in π−p → K0Λ can be measured, based on the well‐known weak Λ‐decay asymmetry. The expected statistical significance of the measurement overrides the best existing data from ‘NIMROD’ detector by an order of magnitude. The experimental setup is under construction at the ITEP proton synchrotron in collaboration with PNPI and ACU.

Search for the Cryptoexotic Member of the Baryon Antidecuplet 1/2+ in the Reactions pi- p --> pi- p and pi- p --> K L

The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the {pi}{sup -}p system invariant mass in the region (1610-1770) MeV with the detection of {pi}{sup -}p and K{lambda} decays. The scan is supposed to be done by the variation of the incident {pi}{sup -} momentum and its measurement with the accuracy of up to {+-}0.1%(better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto-optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at P{sub {pi}} = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the π−p system invariant mass in the region (1610–1770) MeV with the detection of π−p and KΛ decays. The scan is supposed to be done by the variation of the incident π− momentum and its measurement with the accuracy of up to ±0.1% (better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto‐optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at Pπ = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.

Measurement of spin rotation parameter A+ in π +p elastic scattering

Abstract The ITEP-PNPI collaboration presents first results of the spin rotation parameter A+ measurements in the second resonance region. The experiment was performed on ITEP accelerator at positive pion beam momentum 1·43 GeV/c (√s= 1·90 GeV/c) for scattering angles 0cm = 127° and 133°. Main parts of the setup were a polarized proton target and a carbon-plate polarimeter. The results of measurements are in agreement with the predictions of the partial-wave analysis VPI and in contradiction with the predictions of PWAs KH and CMB.