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The ANKE Experiments at COSY: physics program and technical development (including future plans) Andro Kacharava (IKP, FZ Jülich). June 25, 2012 | ANKE/PAX SPIN Physics Workshop. Outline. Introduction Current status of program: Experiments using polarized beams and/or targets

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The ANKE Experiments at COSY:physics program and technical development (including future plans)Andro Kacharava (IKP, FZ Jülich)

June 25, 2012 | ANKE/PAX SPIN Physics Workshop


Outline
Outline

  • Introduction

  • Current status of program:

    • Experiments using polarized beams and/or targets

    • NN scattering program

    • Selected results (pp/pn)

  • Near future:

    • Double-polarized measurements for NN program

    • Towards longitudinally polarized beams – pion program

  • Time line

  • Beyond 2014

ANKE Experiments at COSY


Introduction – COSY Facilities

  • Hadron physics with hadronic probes

  • Experimental set-ups:

    • ANKE

    • WASA

    • EDM

    • (BNL/JEDI)

    • PAX

    • TOF (ext.)

WASA

ANKE

EDM

PAX

TOF

… the machine for

hadron spin physics

Andro Kacharava

ANKE Experiments at COSY

3


Anke cosy advantages of internal exp s
ANKE/COSY – Advantages of Internal Exp.‘s

Feature/ Technique  „Good for“ (examples)

  • Precision / Schottky Luminosity (target density)

  • Spin manipulation / RF  Precise momentum determination,

  • dipole, solenoid systematics

  • Cooling / e-cooler,  Beam quality

  • stochastic

  • Low momentum recoils  On-line polarimetry,

  • Spectator detection effective neutron-target

  • Thin targets  Signal-to-background ratio

  • Gas jet, very thin foils

  • Dense targets  Small x-section measurements

  • Cluster, pellet

  • Large acceptance (near th.) Calibration of spectrometer

  • 2-body kinematics

  • ....


COSY: Tools at ANKE

ANKE

PIT

STT

ANKE Experiments at COSY


Technical developments: PIT/STT

  • Openable cell (target density)

  • 4 STT modules

  • Snake concept

ANKE Experiments at COSY


Technical developments: PIT status

Polarized deuterium (ABS) target:

test measurements at ANKE

using the Lamb-Shift polarimeter

(recent results - May 2012)

ANKE Experiments at COSY


Technical developments: Snake concept

  • Should allow for flexible use at two locations

  • Fast ramping (< 30s)

  • Cryogen-free system

ANKE

ANKE

PAX

PAX

ANKE Experiments at COSY


Physics program overview
Physics program: Overview

1. NN scattering ↔ Nuclear forces

2. Meson production ↔ ChPT, phenomenological models, FSI

3. Hyperon production ↔ SU(3) symmetry

See talks: “Pion program” – S. Dymov

“Eta-meson” – M. Papenbrock

“Hyperon production” – Yu. Valdau

“Kaon-pair production” – A. Dzyuba

Since 2005 ANKE has been equipped with a Polarized Internal Target (PIT)

and embarked to measure the SPIN dependence of many polarized reactions:

New insight into the strong interaction physics at intermediate energies !

► Described in ANKESPIN document:

COSY proposal #152, “Spin Physics from COSY to FAIR” (nucl-ex/0511028)

ANKE Experiments at COSY


Physics program present status
Physics program: Present status

  • Performing single and double polarization experiments;

  • 2 weeks run conducted last week (June 2012) on:

  • ►“Initial research with polarized deuterium target” (exp.201)

  • Preparing approved (un)polarized measurements (PAC #40):

  • ►“NN elastic scattering up to maximum COSY energy” (exp. 212)

  • ► “Measurement of quasi-free pn→dη reaction” (exp.211)

  • ►“Initial research with longitudinal polarized proton beam” (exp.213)

  • Data analysis of previous (un)polarized experiments !

ANKE Experiments at COSY


Nn program pp elastic
NN program: pp elastic

d/d (pp)

  • Description of nucleon-nucleon interaction requires precise data for Phase Shift Analysis

  • COSY-EDDA collaboration produced wealth of data forpp elastic scattering.

  • There are no experimental data at low angles (θcm<30°)above 1.0 GeV energy.

Ay (pp)

EDDA

ANKE

ANKE Experiments at COSY


Nn program np system
NN program: np system

np charge-exchange

  • R. Arndt: “Gross misconception within the community that np amplitudes are known up to a couple of GeV. np data above 800 MeV is a DESERT for experimentalists.”

d/d (np)

ANKE

np charge-exchange

np forward

Ayy (np)

ANKE is able to provide the experimental data both for pp and np systems and improve our understanding of NN interaction

ANKE

np forward

ANKE Experiments at COSY


Experimental program nn interaction

COSY: Polarization observables in npscattering

Experimental program: NN interaction

Unpolarised intensity depends only upon spin-flip amplitudes:

Terms can be separated by measuring with polarised beams/targets:

d and p vector

analysing powers

Unpolarised

cross section

d tensor

analysing powers

d-p vector spin

correlations

d-p tensor spin

correlation

D.V.Bugg & C.Wilkin., Nucl.Phys.A467 (1987) 575

ANKE Experiments at COSY


Np study proof of principle

np study: Proof of principle

dp→{pp}1S0n

  • To check the feasibility of the program first experimental data was taken with deuterium beam at Tn = 600 MeV to compare with tested theoretical predictions:

D.V.Bugg & C.Wilkin., Nucl.Phys.A467 (1987) 575

D. Chiladze et al., PRST-AB 9, 050101 (2006)

D. Chiladze et al., PLB 637, 170 (2006)

D. Chiladze et al., EPJ. A 40 (2009)

dp→(pp)n

Tn = 600 MeV

dp→(pp)n

Tn = 600 MeV

ANKE Experiments at COSY


Status of np program analysing powers
Status of np program: Analysing powers

dp→{pp}1S0n

Tn = 800 MeV

Tn= 1150 MeV

Preliminary

Results differ from theory at Tn=1150 MeV, especially for low transferred momentum region

Tn = 900 MeV

D. Mchedlishvili et al., JP-CS, 295, 012099 (2011)

ANKE Experiments at COSY


Status of np program spin correlations

Status of np program: Spin correlations

dp→(pp)1S0n

Relative phases between the amplitudes

Tn = 1150 MeV

Tn = 600 MeV

Cy,y

Cy,y

Preliminary

Cx,x

Cx,x

ANKE Experiments at COSY


Status of np program dp pp 0
Status of np program: dp → {pp}Δ0

Tn = 800 MeV

dσ/dm

Tn = 800 MeV

Tn = 900 MeV

Tn = 900 MeV

Preliminary

dσ/dm

Tn = 1150 MeV

Tn = 1150 MeV

dσ/dm

D. Mchedlishvili et al., JP-CS, 295, 012099 (2011)

ANKE Experiments at COSY


Status of pp program frequency shift
Status of pp program: Frequency shift

Exp. #200

T0 = 1.0 GeV (η>0)

  • Beam-target interaction gives energy loss that changes the machine frequency.

  • Frequency change depends on η parameter

  • Schottky distribution was recorded in every 10 sec. throughout the 300 sec. cycle.

T0 = 2.0 GeV (η<0)

Meanfrequency

10 sec.

80 sec.

Cycle time

150 sec.

Spectral Density of Schottky Power [arb. units]

220 sec.

290 sec.

1429.45

1429.50

1429.55

1548.10

1548.20

1548.30

Revolution Frequency [kHz]

Revolution Frequency [kHz]

ANKE Experiments at COSY


Status of pp program luminosity
Status of pp program: Luminosity

Exp. #200

1

2

3

4

1

2

3

4

With 2-3 % accuracy

ANKE Experiments at COSY


Status of pp program cross section
Status of pp program: Cross section

Exp. #200

  • Only FD system is used.

  • Reconstructed missing mass of the proton ≈ 938 ± 18 MeV.

Tp = 1.0 GeV

13 - 14°

20 - 21°

27 - 28°

Preliminary

SAID

SAID

SAID

 ANKE

 ANKE

 ANKE

Tp = 2.8 GeV

Tp = 2.0 GeV

ANKE Experiments at COSY


Near future two examples
Near future: Two examples

Next PAC meeting (#41)

  • Double-polarized measurements for NN sector (Exp.“212.1“)

    requirements: pol. beam, pol. target (D), 4 STT‘s, openable cell,

    roughly ~ 7-8 weeks of BT

  • Axz measurement for pion production (Exp. “213.1“)

    requirements: + [email protected], roughly ~ 10 weeks of BT

  • Synergy (and coordination) with PAX and TRIC Exp.‘s !

ANKE Experiments at COSY


Time line up to 2014
Time line: up to 2014

↓___↓____________________↓__ 2012

PAC#40 Exp. 201 Snake delivery

____↓____I ANKE BTI___ ↓ __________________↓________ 2013

SnakeExp.s: 211, 212 PAC#41 Double-pol. (Exp. 212.1)

@PAX

____↓_____________↓_____________↓__________↓_ 2014

Exp. 213.1 (Axz) PAC#42 Double-pol. (Exp.#???) [email protected]

ANKE Experiments at COSY


Time line beyond 2014
Time line: beyond 2014

Examples (PAC #42):

  • Explore longitudinal polarized beam for spin observables in NN sector

  • Develop concept and start to create polarimetry data base for the COSY EDM project via measurement of spin dependence of the pp, pd and dp elastic processes

  • Strangeness production – (Λn) scattering length: singlet (as) and triplet (at) part separately via spin correlation parameter (Cyy) measurements

    (► depends on TOF result on Λp system)

ANKE Experiments at COSY


The end
The END

  • Many thanks to the workshop organizers !



Spare transparencies

ANKE Experiments at COSY


Strangeness production: YN Interaction

ΛNscatteringlength: singlet (as) andtriplet (at) partseparately

  • Poor data base:

  • - LN little known

  • - SN nothing known

  • YN scattering experiments difficult

  •  large uncertainty in Lp scattering length

  • Theory

  • Model-freedetermination in productionreactions

  • Method:dispersionrelations

  • Theoryprecisionis 0.3 fm

  • Spin/isospin dependence

  • TOF:high-resolutionsinglepolarized

  • p+p→K+(Λp)at(θK,cm = 90°) at

  • ANKE:double polarized p+n→K+(Λn)

  • (1 – CNN)·σ at (θK,cm= 0°)  as

A. Gasparyan et al., PRC 69, 034006 (2004)

ANKE Experiments at COSY


2005-2009

2010-2014

COSY proposal #152

ArXiv:nucl-ex/0511028


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