catalina petrascu (curceanu) for the dear collaboration 26th lnf scientific committee meeting

Catalina Petrascu (Curceanu)Catalina Petrascu (Curceanu)for the DEAR Collaboration

26th LNF Scientific Committee meeting

Frascati, 29 – 30 May 2003

D E A RD E A R

eXperiment

DANE Exotic

Atoms Research

D E A RD E A R

eXperiment

DANE Exotic

Atoms Research

ContentsContents

1. Introduction

2. Kaonic nitrogen: final results

3. Kaonic hydrogen: preliminary results on all the statistics

4. The DEAR scientific program: where we stand

5. Future plans

D E A RD E A R

eXperiment

DANE Exotic

Atoms Research

D E A RD E A R

eXperiment

DANE Exotic

Atoms Research

1. Introduction1. Introduction

Having optimized:

- DANE for DEAR (luminosity and background);

- DEAR: shielding and setup

APD Cryo Cooler

Varian Turbo Molecular Pump

CryoTiger, CCD Cooling

CCD Electronics

Vacuum Chamber

Hydrogen Target Cell

CCD Pre-Amplifier Boards

Cooling Lines

CCD55-Chip (total of 16 chips)

DEAR DEAR Cryogenic setupCryogenic setup

Kaons from DANE

DEAR Cryogenic Target CellDEAR Cryogenic Target Cell

CCD-55 mounting,cryogenics and

on-cell electronics

- fiber-glass frames

- cooling system mounted on the top

- minimized Al cold finger (behind CCDs)

- reduced diameter of the socket group and, consequently, of the vacuum chamber

DEAR shielding

Pb walls

Quadrupole shield

Pb platform

Vacuum jacket shielding

Overall shielding factor Overall shielding factor of the DEAR interaction region ~ 100of the DEAR interaction region ~ 100

Lead shielding

Target

November – December 2002 – kaonic

hydrogen measurement performed

DEAR on DADEAR on DANE autumn 2002NE autumn 2002

October – December 2002 DAQ

Collected data:

-Kaonic Nitrogen:6 – 28 October (about 17 pb-1 – 10 pb-1 in stable conditions);

-Kaonic Hydrogen:30 October – 16 December: about 60 pb-1

-Background data (no collisions) for KH:16 – 23 December

The first phase of the DEAR Scientific program is completed

Results of this phase are hereby presented

2. Kaonic nitrogen: final results2. Kaonic nitrogen: final results

Objectives of kaonic nitrogen Objectives of kaonic nitrogen measurementmeasurement

# Background study and reduction; optimization of the kaon stopping point distribution (i.e. degrader shaping)

# First exotic atom measurement at DANE

# KN Physics: - yield measurements (exotic atom cascade);

- test of a future precision measurement of the charged kaon mass

Kaonic nitrogen:Kaonic nitrogen:2002 final results2002 final results

Kaonic NitrogenKaonic Nitrogen (October 2002)(October 2002) integrated luminosity 10 pb-1

(T = 85 K, P = 1.01 bar, density = 4.4 g/l)

Pattern of 3

transitions:

7 -> 6 at 4.6 keV

6 -> 5 at 7.6 keV

5 -> 4 at 14.0 keV

Kaonic Nitrogen, 10 pbKaonic Nitrogen, 10 pb-1 -1 (October 2002)(October 2002)Background subtracted spectrumBackground subtracted spectrum

Pattern of 3 lines:

2690 +/- 650 ev. at 4.6 keV

5320 +/- 395 ev. at 7.6 keV

1360 +/- 330 ev. at 14.0 keV

• First determination of the yield of 3 Kaonic Nitrogen X-ray transitions:

7 6 (33.7 +/- 8.1 +/- 3.4)% 6 5 (55.5 +/- 4.2 +/- 5.5)% 5 4 ( 66.4 +/- 15.6 +/- 6.4)%

• Mass of the kaon – as a test measurement:

mK- = 493.884 +/- 0.314 MeV

(Ph. D. thesis, paper to be submitted to Phys. Lett. B)

Kaonic Nitrogen PhysicsKaonic Nitrogen Physics

3. Kaonic hydrogen3. Kaonic hydrogen(November – December 2002)(November – December 2002)

- preliminary results -- preliminary results -

Last Committee (November Last Committee (November 2002) presentation:2002) presentation:

First Kaonic Hydrogen at DAFirst Kaonic Hydrogen at DANE (Nov. 2002)NE (Nov. 2002)

integrated luminosity: 20 pb20 pb-1-1

Kaonic Hydrogen Kaonic Hydrogen 1800 events in 6.3 keV-region: 1800 events in 6.3 keV-region: 500 events Fe 500 events Fe + 1300 events KH 1300 events KH

JZ / 26.11.02

extrapolated

7000 events K

14000 events K-complex

Kaonic Hydrogen,Kaonic Hydrogen, 80 pb80 pb-1 -1

Monte Carlo simulated spectrum

~

-1

33eV

Request to the 25th Scientific CommitteeRequest to the 25th Scientific Committee

# To continue until we get an integrated luminosity

of at least 80 pb-1 to permit a measurement

at the level of ~ 33 eV, assuming the present

machine conditions.

What we have obtained:What we have obtained:

# 60 pb-1 of integrated luminosity which allowed

(very preliminary result) a measurement at the level

of ~ 40 eV

Two independent analyses were Two independent analyses were performed:performed:

- a global fit of the KH spectrum;- a global fit of the KH spectrum;

- a (measured) background - a (measured) background subtracted spectral analysissubtracted spectral analysis

I) GLOBAL FIT OF KH spectrumI) GLOBAL FIT OF KH spectrum

?

Kaonic Hydrogen Kaonic Hydrogen (2002 data)- global fit(2002 data)- global fit

integrated luminosity: 60 pb60 pb-1-1

4 6 8 10 12 14 16

0

20000

40000

60000

80000

100000

120000

KKcomplex

X-ray energy (KeV)

Eve

nts

/ 60

eV

Kaonic Hydrogen Kaonic Hydrogen (2002 data)- global fit(2002 data)- global fit

Background + Fe subtracted spectrum

5 6 7 8 9 10 11

0

500

1000

1500

2000

2500

KKcomplex

X-ray energy (KeV)

Eve

nts

/ 60

eV

124

Ca

TiAu - L

PbAu - L

= (160 +/- 30 +/- 15) eV = (165 +/- 50 +/- ?) eV

KC

K = 3300 +/- 1200 ev.

Kcompl = 6600 +/- 2000

?

II) Measured background II) Measured background subtracted spectral analysissubtracted spectral analysis

Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)

Measured Kaonic Hydrogen spectrum

K

Kcomplex


Measured background spectrum


Divided spectrum

No Ti

No Ca

No Fe


Normalized measured spectra

K

Kcomplex


Measured background subtracted spectrum

?

= (165 +/- 40) eV = (240 +/- 86) eV

K = 3000 +/- 1400 ev.

Kcomplex= 7000 +/- 2400


Measured background subtracted spectrum - smoothed

?

Results of the KH analyses:Results of the KH analyses:(Very preliminary)

Two independent preliminary analyses of the 60 pb-1 collected data were performed – results in very good agreement:

= (162 +/- 40) eV

= ~( 200+/- 80) eV

K = 3100 +/- 1300 ev.

Kcomplex= 6800 +/- 2400

4. The DEAR scientific 4. The DEAR scientific program: where we standprogram: where we stand

DEAR and the rest of the worldDEAR and the rest of the world

The obtained results:

represent the best measurement performed on Kaonic Hydrogen up to now

= (162 +/- 40) eV

= (200+/- 80) eV

Iwas

aki e

t al,

1997

KpX

-500 50000

200

400

600

800

1000

Shift (eV) [

Dav

ies

et a

l, 19

79

Izyc

ki e

t al,

1980

Bir

d et

al,

1983

Constant Scattering LengthK-MatrixPotential ModelCloudy Bag ModelConsituent Quark Model

DEARpreliminary

result

Kaonic hydrogen: summary of data

Wid

th (

eV) [

]

MORE on KH analysis:MORE on KH analysis:

1) Refine quality of data – Charge Transfer corrections

2) Finalize the analysis with the good quality data

3) Careful study of the systematic errors

4) Interpretation of the results: challenge for theorist

SPRING SCHOOL 19-23 May - contact with Bern and Bonn

groups (Gasser, Rusetsky: Ph. D. Student on KH interpretation

– revival of interest)

5. Future plans5. Future plans

Next Steps of the DEAR Scientific Program

# few eV precision measurement of kaonic kaonic hydrogenhydrogen 1s level shift;

# few eV precision measurement of kaonic kaonic deuteriumdeuterium 1s level shift

in order to determine the isospin dependent in order to determine the isospin dependent antikaonantikaon

nucleon scattering lengths at percent level nucleon scattering lengths at percent level precisionprecision

Monte Carlo simulations with the SDD triggerable setup(see talk of C. Fiorini)

# Percent precision measurement of kaonic kaonic hydrogenhydrogen transition – with 50 pb-1;

Kaonic Hydrogen Kaonic Hydrogen Monte Carlo simulation in realistic conditionsMonte Carlo simulation in realistic conditions

Precision on shift ~ 3 eV

50 pb-1

S/B = 1/1

Further plans

# Kaonic helium measurement (“kaonic helium puzzle”);

# Other light kaonic atoms measurement (Li, Be…);

# Charged kaon mass precision measurement

# Investigate the possibility of the measurement of other types of hadronic exotic atoms (sigmonium?)

How to reach these goals?

NEXT TALK…..(C. Fiorini – Politecnico di Milano)

AcknowledgementsAcknowledgements

The DANE machine staff is warmly thanked by the DEAR group.

The success of the difficult kaonic hydrogen measurement has its origin in a happy

collaboration machine – experiment, which has been continuously enriched by new

ideas and clever solutions to all problems.

catalina petrascu (curceanu) for the dear collaboration 26th lnf scientific committee meeting

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