Analysis of narrow structures in the pion nucleon elastic - - PowerPoint PPT Presentation

▶

May 17, 2023 280 likes •573 views

Analysis of narrow structures in the pion nucleon elastic scattering data from the EPECUR experiment. I,G. Alekseev, I.G. Bordyuzhin, D.A. Fedin, V.P. Kanavets , L.I. Koroleva, B.V. Morozov, V.M. Nesterov, V.V. Ryltsov, D.N. Svirida, A.D.

SLIDE 1

Analysis of narrow structures in the pion nucleon elastic scattering data from the EPECUR experiment.

I,G. Alekseev, I.G. Bordyuzhin, D.A. Fedin, V.P. Kanavets , L.I. Koroleva, B.V. Morozov, V.M. Nesterov, V.V. Ryltsov, D.N. Svirida, A.D. Sulimov ITEP, Moscow V.A. Andreev, Ye.A. Filimonov, A.B. Gridnev, V.V. Golubev, A.I. Kovalev, N.G. Kozlenko, V.S. Kozlov, A.G. Krivshich, D.V. Novinsky, V.V. Sumachev, V.I. Tarakanov, V.Yu. Trautman, PNPI, Gatchina

M. Sadler, ACU, Abilene

SLIDE 2

HSQCD 2014 N.G. Kozlenko PNPI

Pentaquark antidecuplet

ЃЌЃЏђ ќ ђ Ѓ

D.Diakonov et al. Z.Phys. A359, 1997, 305 [10] Spin = 1/2

Isospin = 0 Strangeness = +1 Mass ~1.530MeV Г ~ 15 MeV

?

prediction – N***(Original 1710)

From modified PWA – 1680

R. Arndt, Ya. Azimov, M. Polyakov,

IS, R. Workman, Phys Rev C 69, 035208 (2004)

SLIDE 3

Why pions? Theory gives weak coupling to πN sector. Advantages:

1. The structure of the πN amplitude is much more simpler

than in photoproduction 2.The πN partials waves are known very well from phase shift analysis. 3.There is isospin symmetry.

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 4

HSQCD 2014 N.G. Kozlenko PNPI

Pion beam Line (N322) at ITEP (Moscow)

SLIDE 5

Setup for elastic scattering “EPECUR”

HSQCD 2014 N.G. Kozlenko PNPI

 Proportional chambers: (1FCH1-4) - the first focus and (2FCH1-4) - before the target.  LqH2 - Hydrogen target  DC[N] - drift chambers.  S1, S2, A1 - Scintillation counters

DC1-4 DC5-8

pp

SLIDE 6

HSQCD 2014 N.G. Kozlenko PNPI

What is special in our experiment:

“Formation”–type experiment (s-channel).
Extremely high invariant mass resolution (~0.6 MeV), provided

by high momentum resolution of the magneto-optic channel 0.1%.

Magnetless spectrometer with drift chambers.
Liquid hydrogen target.
Very small amount of matter on the particle paths.
High statistical precision: better 1% .

SLIDE 7

HSQCD 2014 N.G. Kozlenko PNPI

Forum for MAX-IV Ring, Lund, Nov 2011

ˉ p  ˉ p

SLIDE 8

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  ˉ p

partial wave analysis from GWU (WI08)
EPECUR results

SLIDE 9

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  ˉ p

partial wave analysis from GWU (WI08)
EPECUR results

SLIDE 10

HSQCD 2014 N.G. Kozlenko PNPI

partial wave amplitudes from GWU analysis

+ p  + p

SLIDE 11

HSQCD 2014 N.G. Kozlenko PNPI

+ p  + p

partial wave amplitudes from GWU analysis

SLIDE 12

Now we will try to describe the observed structures using the two resonances, and for that we will use:

K-matrix approach with effective Lagrangians.

P.F.A. Goudsmit et al Nucl.Phys A575 (1994)673 A.B. Gridnev, N.G. Kozlenko. Eur.Phys.J.A4:187-194, (1999).

T. Feuster and U. Mosel Phys. Rec. C 58 457 (1998).

It is assumed that the K-matrix, being a solution of the equation for scattering amplitude, can be considered as a sum of the tree- level Feynman diagrams with the effective Lagrangians in the vertices.

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 13

We included: 4* resonances from PDG in s and u channels and σ , ρ like exchange in t channel. Multichannel:

1. elastic scattering
2. two pion production(effective)
3. η n production
4. K Λ production
5. K Σ production

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 14

Free parameters → coupling constants and masses. We concentrate on elastic scattering and treat inelastic channels approximately to save the number of free parameters. Database:

EPECURE results
PWA GWU single energy solutions up to 1GeV/c
η n total cross section
K Λ differential cross section
K0 Σ0 differential cross section
K+ Σ+ differential cross section
K+ Σ - differential cross section

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 15

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  ˉ p

partial wave amplitudes from GWU analysis
K-matrix analysis
EPECUR results

SLIDE 16

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  ˉ p

SLIDE 17

HSQCD 2014 N.G. Kozlenko PNPI

+ p  + p

SLIDE 18

HSQCD 2014 N.G. Kozlenko PNPI

+ p  + p

SLIDE 19

HSQCD 2014 N.G. Kozlenko PNPI

Single Energy partial wave amplitude from GWU analysis
K-matrix analysis

SLIDE 20

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  η n

SLIDE 21

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  Kº Λ

SLIDE 22

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  Kº Λ

SLIDE 23

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  Kº Σº

SLIDE 24

HSQCD 2014 N.G. Kozlenko PNPI

ˉ p  K Σˉ +

SLIDE 25

Very preliminary

S11 M=1686(1.5) Γtot=18.2 MeV Γel=0.1 MeV Γ2π=10.0 MeV Γήn=8.0 MeV ΓKΛ=0.1 MeV P11 M=1710(2.0) Γtot=25.0 MeV Γel=0.25 MeV Γ2π=10.0 MeV Γήn=5.1 MeV ΓKΛ=0.25 MeV ΓKΣ=9.0 MeV

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 26

M=1686 S11 →P11→ χ2 ↑ 15% M=1710 P11 →S11→ χ2 ↑ 25%

Another explanations (for η photoproduction) 1.Interference effects. Interference of well-known resonances Interference of S11(1650) and P11(1710) .

V. Shklyar, H. Lenske , U. Mosel , PLB650 (2007) 172 (Giessen group )

Interference of S11(1535) and S11(1650) .

A. Anisovich et al. EPJA 41, 13 (2009) (Bonn-Gatchina group);

We not found such solution 2.Cusp effect M.Doring, K. Nakayama, PLB B683:145 (2010) We are working on this possibility 26

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 27

Conclusions

The observed structures in the differential cross section
f the π¯p elastic scattering can be described by two

narrow resonances S11(1686) and P11(1710).

Further investigation on the nature of this structures

requires more precise data for inelastic channels of π¯p reaction.

HSQCD 2014 N.G. Kozlenko PNPI

SLIDE 28

Thank you for your attention!

HSQCD 2014 N.G. Kozlenko PNPI