A Partial-Wave Analysis of Centrally Produced Two-Pseudoscalar Final - - PowerPoint PPT Presentation

▶
a partial wave analysis of centrally produced two
SMART_READER_LITE
LIVE PREVIEW

A Partial-Wave Analysis of Centrally Produced Two-Pseudoscalar Final - - PowerPoint PPT Presentation

Jan 03, 2023 137 likes •485 views

A Partial-Wave Analysis of Centrally Produced Two-Pseudoscalar Final States in pp Reactions at COMPASS Alexander Austregesilo for the COMPASS Collaboration ATHOS 2013 May 21-24, 2013 COMPASS Supported by Introduction Partial-Wave Analysis

slide-1
SLIDE 1

A Partial-Wave Analysis of Centrally Produced Two-Pseudoscalar Final States in pp Reactions at COMPASS

Alexander Austregesilo for the COMPASS Collaboration ATHOS 2013 May 21-24, 2013

COMPASS Supported by

slide-2
SLIDE 2

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Outline

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

2/17

slide-3
SLIDE 3

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

The COMPASS Experiment

Multi-Purpose Setup Fixed-target experiment @ CERN SPS Two-stage magnetic spectrometer Broad kinematic range Tracking, calorimetry, particle ID

COMPASS

CEDARs RICH target + RPD SM1 SM2 E/HCAL

Data Set 190 GeV/c proton beam Liquid H2 target Trigger on recoil proton

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

3/17

slide-4
SLIDE 4

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Central Production

F Feynman x
  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2
0.2 0.4 0.6 0.8 1 Entries 0.1 0.2 0.3 0.4 0.5 6 10 ×

COMPASS 2009

s p
  • π
+ π f p → p p s

p

  • π
+

π

f

p

2 ) > / 2.0 GeV/c π M(p 1.5

p r e l i m i n a r y

p p → pfast X pslow Proton beam impinging on liquid hydrogen target Double-Pomeron Exchange as glue-rich environment ⇒ Production of non-q¯ q-mesons (Glue Balls, Hybrids) at central rapidities

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

4/17

slide-5
SLIDE 5

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Central Production

) 2 System (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2 Events / 5MeV/c 0.02 0.04 0.06 0.08 0.1 0.12 6 10 × COMPASS 2009 s p
  • π
+ π f p → p p (1270) 2 f (980) f (770) ρ

p r e l i m i n a r y

) 2 System (GeV/c
  • K
+ Invariant Mass of K 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2 Events / 5MeV/c 1 2 3 4 5 6 7 8 9 3 10 × COMPASS 2009 s p
  • K
+ K f p → p p

p r e l i m i n a r y

p p → pfast X pslow Proton beam impinging on liquid hydrogen target Double-Pomeron Exchange as glue-rich environment ⇒ Production of non-q¯ q-mesons (Glue Balls, Hybrids) at central rapidities Decay into two-pseudoscalar final state (π+π−, π0π0, K +K −, η η, ..)

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

4/17

slide-6
SLIDE 6

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Two-Body Partial-Wave Analysis in Mass Bins

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

5/17

slide-7
SLIDE 7

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Partial-Wave Analysis

) 2 (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ) θ cos(
  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2
0.2 0.4 0.6 0.8 1 COMPASS 2009 s p
  • π
+ π f p → p p

p r e l i m i n a r y

(GeV/c^2)
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 φ
  • 3
  • 2
  • 1
1 2 3 COMPASS 2009 s p
  • π
+ π f p → p p

p r e l i m i n a r y X → π+π− Assumption: collision of two space-like exchange particles (P, R) Decay fully described by M(π+π−), cos(θ) and φ

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

6/17

slide-8
SLIDE 8

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Partial-Wave Analysis

) 2 (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ) θ cos(
  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2
0.2 0.4 0.6 0.8 1 COMPASS 2009 s p
  • π
+ π f p → p p

p r e l i m i n a r y

(GeV/c^2)
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 φ
  • 3
  • 2
  • 1
1 2 3 COMPASS 2009 s p
  • π
+ π f p → p p

p r e l i m i n a r y X → π+π− Assumption: collision of two space-like exchange particles (P, R) Decay fully described by M(π+π−), cos(θ) and φ Fit complex production amplitudes in mass bins to match spin contributions and interference pattern

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

6/17

slide-9
SLIDE 9

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Construction of Wave-Set

Strong Interaction Conserves Parity Linear combination of spherical harmonics as eigenstates of reflectivity ǫ, limiting the spin projection m ≥ 0, waves with opposite ǫ do not interfere Y ǫℓ

m (θ, φ) = c(m)

  • Y ℓ

m(θ, φ) − ǫ(−1)mY ℓ −m(θ, φ)

  • Naturality

Minus-sign was chosen such that reflectivity coincide with exchanged naturality η for reaction with pion beam ’Pomeron beam’ has opposite parity → η = −ǫ For central production, natural transfers (JP = 0+, 1−, 2+, ...) correspond to ǫ = −1 and are expected to dominate

Techniques of amplitude analysis for two-pseudoscalar systems S.-U. Chung, [Phys. Rev. D 56 (1997), 7299]

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

7/17

slide-10
SLIDE 10

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Partial-Wave Decomposition

Expand intensity I(θ, φ) in terms of partial-waves for narrow mass bins: I(θ, φ) =

  • ε
  • ℓm

TεℓmY εℓ

m (θ, φ)

  • 2

Complex transition amplitudes Tεℓm, no dynamics Explicit incoherent sum over the reflectivities ε Spectroscopic notation: ℓǫ

m

Significant contributions only from ℓ = S, P, D, m ≤ 1 ⇒ Maximum Likelihood Fit in Mass Bins

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

8/17

slide-11
SLIDE 11

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Partial-Wave Decomposition

Expand intensity I(θ, φ) in terms of partial-waves for narrow mass bins: I(θ, φ) =

  • ε
  • ℓm

TεℓmY εℓ

m (θ, φ)

  • 2

Complex transition amplitudes Tεℓm, no dynamics Explicit incoherent sum over the reflectivities ε Spectroscopic notation: ℓǫ

m

Significant contributions only from ℓ = S, P, D, m ≤ 1 ⇒ Maximum Likelihood Fit in Mass Bins Inherent Ambiguities of Two-Pseudoscalar Final State Intensity can also be expressed as a 4th-order polynomial Complex conjugation of the roots (’Barrelet zeros’) results in the same angular distribution, i.e. the same likelihood

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

8/17

slide-12
SLIDE 12

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Barrelet Zeros

)

2

System (GeV/c

  • π
+

π Invariant Mass of 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 )

k

Re(u

  • 3
  • 2
  • 1

1 2 3

COMPASS 2009

s p
  • π
+ π f p → p p

p r e l i m i n a r y

)

2

System (GeV/c

  • π
+

π Invariant Mass of 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 )

k

Im(u

  • 2
  • 1.5
  • 1
  • 0.5

0.5 1 1.5 2

COMPASS 2009

s p
  • π
+ π f p → p p

p r e l i m i n a r y

Real (left) and imaginary (right) part of polynomial roots Well separated, imaginary parts do not cross the real axis ⇒ Solutions can be uniquely identified, no linking procedure necessary

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

9/17

slide-13
SLIDE 13

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Ambiguities in the π+π− System

8 different solutions can be calculated analytically Differentiation requires additional input (e.g. behaviour at threshold, physics content)

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

10/17

slide-14
SLIDE 14

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Fit to the π0π0 System

Identical particles, only even waves allowed Reduces number of ambiguities to 2, choice by S-wave dominance at threshold

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

11/17

slide-15
SLIDE 15

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Fit to the ππ Systems

Consistent picture of symmetric reaction, measured with different parts of experimental setup ρ(770) signal cannot be described by this model, different production mechanism Interpretation with mass dependent parametrisation under way!

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

12/17

slide-16
SLIDE 16

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Fit to the K +K − System

preliminary

)

2

(GeV/c

  • K
+

Invariant Mass of K

1.2 1.4 1.6 1.8 2 2.2 2.4 2

Intensity / 10MeV/c

20 40 60 80 100 3 10 ×
  • S

)

2

(GeV/c

  • K
+

Invariant Mass of K

1.2 1.4 1.6 1.8 2 2.2 2.4 2

Intensity / 10MeV/c

1 2 3 4 5 6 7 3 10 ×
  • D

)

2

(GeV/c

  • K
+

Invariant Mass of K

1.2 1.4 1.6 1.8 2 2.2 2.4 2

Intensity / 10MeV/c

1 2 3 4 5 6 7 8 3 10 ×
  • 1

D

1.2 1.4 1.6 1.8 2 2.2 2.4 20 40 60 80 100 120 140 160 180 1.2 1.4 1.6 1.8 2 2.2 2.4
  • 20
20 40 60 80 100 1.2 1.4 1.6 1.8 2 2.2 2.4 50 100 150 200

)

2

(GeV/c

  • K
+

Invariant Mass of K

1.2 1.4 1.6 1.8 2 2.2 2.4 2

Intensity / 10MeV/c

0.5 1 1.5 2 2.5 3 3.5 3 10 ×

+ 1

D

COMPASS 2009

s

p

  • K
+

K

f

p → p p

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

13/17

slide-17
SLIDE 17

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Mass-Dependent Parametrisation of K +K −-System

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

14/17

slide-18
SLIDE 18

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Parametrisation

S0-Wave

Relativistic Breit-Wigner parametrisation: f0(1370), f0(1500), f0(1710)

D0-Wave

Relativistic Breit-Wigner parametrisation: f2(1270), f ′

2(1525)

Coherent Background

Phase space factor qℓ ·

  • q

m2 with breakup momentum q

Exponential background exp(−αq − βq2) with fit parameters α, β

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

15/17

slide-19
SLIDE 19

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Parametrisation

S0-Wave

Relativistic Breit-Wigner parametrisation: f0(1370), f0(1500), f0(1710)

D0-Wave

Relativistic Breit-Wigner parametrisation: f2(1270), f ′

2(1525)

Coherent Background

Phase space factor qℓ ·

  • q

m2 with breakup momentum q

Exponential background exp(−αq − βq2) with fit parameters α, β In total: 27 parameters

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

15/17

slide-20
SLIDE 20

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Intensities and Phase

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 2 Intensity / 10MeV/c 20 40 60 80 100 3 10 ×

COMPASS 2009

s p
  • K
+ K f p → p p

preliminary

Intensity of S0 wave

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 Phase 20 40 60 80 100 120 140 160 180

COMPASS 2009

s p
  • K
+ K f p → p p

preliminary

arg(S0 / D0)

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 2 Intensity / 10MeV/c 1 2 3 4 5 6 7 8 3 10 ×

COMPASS 2009

s p
  • K
+ K f p → p p

preliminary

Intensity of D0 wave

BW contributions background coherent sum

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

16/17

slide-21
SLIDE 21

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Intensities and Phase

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 ) 2 Intensity / (10MeV/c 3 10 4 10 5 10

COMPASS 2009

s p
  • K
+ K f p → p p

p r e l i m i n a r y

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 Phase 20 40 60 80 100 120 140 160 180

COMPASS 2009

s p
  • K
+ K f p → p p

p r e l i m i n a r y

) 2 (GeV/c
  • K
+ Invariant Mass of K 1.2 1.4 1.6 1.8 2 2.2 2.4 ) 2 Intensity / (10MeV/c 1 2 3 4 5 6 7 8 3 10 ×

COMPASS 2009

s p
  • K
+ K f p → p p

p r e l i m i n a r y

BW contributions background coherent sum

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

16/17

slide-22
SLIDE 22

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Conclusion

Summary

Centrally produced two-pseudoscalar final states Order-of-magnitude larger sample than previous experiments (for charged channels) Performed acceptance corrected PWA Studied mathematically ambiguous solutions Simple mass-dependent parametrisation can describe the K +K − fit Breit-Wigner parameters mostly consistent with PDG values

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

17/17

slide-23
SLIDE 23

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Conclusion

Summary

Centrally produced two-pseudoscalar final states Order-of-magnitude larger sample than previous experiments (for charged channels) Performed acceptance corrected PWA Studied mathematically ambiguous solutions Simple mass-dependent parametrisation can describe the K +K − fit Breit-Wigner parameters mostly consistent with PDG values

Outlook

Unitary models (K-matrix, ..) Combined fit of all available channels Include production kinematics (t1, t2, ϕ) Information about the composition of supernumerous scalar resonances

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

17/17

slide-24
SLIDE 24

Introduction Partial-Wave Analysis in Mass Bins Mass-Dependent Parametrisation Conclusion and Outlook

Conclusion

Summary

Centrally produced two-pseudoscalar final states Order-of-magnitude larger sample than previous experiments (for charged channels) Performed acceptance corrected PWA Studied mathematically ambiguous solutions Simple mass-dependent parametrisation can describe the K +K − fit Breit-Wigner parameters mostly consistent with PDG values

Outlook

Unitary models (K-matrix, ..) Combined fit of all available channels Include production kinematics (t1, t2, ϕ) Information about the composition of supernumerous scalar resonances

Thank you for your attention!

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

17/17

slide-25
SLIDE 25

Backup

Central Production

Kinematic Selection m(pπ) > 1.5 GeV/c2 p(pf ) > 170 GeV/c |y(π+π−)| < 1

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

18/17

slide-26
SLIDE 26

Backup

Kinematic Selection

DD: double diffraction (= central production) DSRE: diffractive single resonance excitation

P . Lebiedowicz and A. Szczurek, [Phys. Rev. D 81 (2010), 36003]

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

19/17

slide-27
SLIDE 27

Backup

Glueball Filter

) 2 System (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2 Events / 5MeV/c 1 2 3 4 5 6 3 10 ×

COMPASS 2009

s p
  • π
+ π f p → p p

preliminary

) 2 System (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2 Events / 5MeV/c 2 4 6 8 10 12 14 3 10 ×

COMPASS 2009

s p
  • π
+ π f p → p p

preliminary

) 2 System (GeV/c
  • π
+ π Invariant Mass of 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2 Events / 5MeV/c 2 4 6 8 10 12 14 16 3 10 ×

COMPASS 2009

s p
  • π
+ π f p → p p

preliminary

dPT = |− → p T1 − − → p T2| in pp centre-of-mass Only scalar signals remain for small dPt

A.Kirk, [Phys. Atom. Nucl. 62 (1999) 398]

dPT ≤ 0.2 GeV/c 0.2 ≤ dPT < 0.5 GeV/c dPT ≥ 0.5 GeV/c

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

20/17

slide-28
SLIDE 28

Backup

Maximum Likelihood Fit in Mass Bins

Maximise likelihood function ln L =

N

  • i=1

ln I(θi, φi) −

  • dΩ I(θ, φ) η(θ, φ)

by choosing Tεℓm such that the intensity fits the observed N events the normalisation integral is evaluated by a phase-space Monte Carlo sample with the acceptance η(θ, φ)

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

21/17

slide-29
SLIDE 29

Backup

Barrelet Zeros

Through variable transformation u = tan(θ/2), angular distribution for this wave set can be written as a function of |G(u)|2 with G(u) = a4u4 − a3u3 + a2u2 − a1u + a0 where coefficients ai are functions of amplitudes

  • r with in terms of 4 complex roots ui (’Barrelet zeros’)

G(u) = a4(u − u1)(u − u2)(u − u3)(u − u4) Laguerre’s method to find polynomial roots numerically Complex conjugation of one/more of these roots result in the same measured angular distribution → 8 different ambiguous solutions (same likelihood per definition!)

Techniques of amplitude analysis for two-pseudoscalar systems S.U. Chung, [Phys. Rev. D 56 (1997), 7299]

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

22/17

slide-30
SLIDE 30

Backup

Evaluation of Fit with Weighted MC

) θ cos(

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1

Entries 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

3

10 ×

2

(0.99, 1.09) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

(rad) φ

  • 3
  • 2
  • 1

1 2 3

Entries 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

3

10 ×

2

(0.99, 1.09) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

Blue: data, red: weighted MC

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

23/17

slide-31
SLIDE 31

Backup

Evaluation of Fit with Weighted MC

) θ cos(

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1

Entries 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

3

10 ×

2

(1.29, 1.39) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

(rad) φ

  • 3
  • 2
  • 1

1 2 3

Entries 0.2 0.4 0.6 0.8 1

3

10 ×

2

(1.29, 1.39) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

Blue: data, red: weighted MC

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

23/17

slide-32
SLIDE 32

Backup

Evaluation of Fit with Weighted MC

) θ cos(

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1

Entries 100 200 300 400 500 600 700 800 900

2

(1.59, 1.69) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

(rad) φ

  • 3
  • 2
  • 1

1 2 3

Entries 100 200 300 400 500 600 700

2

(1.59, 1.69) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

Blue: data, red: weighted MC

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

23/17

slide-33
SLIDE 33

Backup

Evaluation of Fit with Weighted MC

) θ cos(

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1

Entries 50 100 150 200 250 300 350 400

2

(2.19, 2.29) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

(rad) φ

  • 3
  • 2
  • 1

1 2 3

Entries 20 40 60 80 100

2

(2.19, 2.29) GeV/c

COMPASS 2009

s

p

  • K
+

K

f

p → p p

p r e l i m i n a r y

Blue: data, red: weighted MC Peaking distribution for |cos(θ)| > 0.9 for masses above 2 GeV/c2 cannot be described by fit (limited wave set) Signature of diffractive dissociation background

  • A. Austregesilo (aaust@cern.ch) — PWA of Centrally Produced Two-Pseudoscalar System at COMPASS

23/17