Alessandro Scordo Alessandro Scordo

LNF – INFN, FrascatiLNF – INFN, FrascatiSIDDHARTA CollaborationSIDDHARTA Collaboration

Frascati – Spring SchoolFrascati – Spring School, 12/05/08, 12/05/08 – 16/05/08 – 16/05/08

SIDDHARTA ExperimentSIDDHARTA Experiment

LNF- INFN, Frascati, ItalyLNF- INFN, Frascati, Italy

IMEP- ÖAW, Vienna, AustriaIMEP- ÖAW, Vienna, Austria

IFIN – HH, Bucharest, RomaniaIFIN – HH, Bucharest, Romania

Politecnico, Milano, ItalyPolitecnico, Milano, Italy

MPE, Garching, GermanyMPE, Garching, Germany

PNSensors, Munich, GermanyPNSensors, Munich, Germany

RIKEN, JapanRIKEN, Japan

Univ. Tokyo, JapanUniv. Tokyo, Japan

Victoria Univ., Canada Victoria Univ., Canada

SISIlicon licon DDrift rift DDetector for etector for HHadronic adronic AAtom tom RResearch by esearch by TTiming iming AApplicationspplications

SIDDHARTA ExperimentSIDDHARTA Experiment((SISIlicon licon DDrift rift DDetector for etector for HHadronic adronic AAtom tom RResearch by esearch by

TTiming iming AApplication)pplication)

1.1. High precision (High precision (~eV) m~eV) measurement of width easurement of width

and shift of Kaonic Hydrogen Kand shift of Kaonic Hydrogen K transition transition

2.2. First measurement of Kaonic DeuteriumFirst measurement of Kaonic Deuterium

Experimental Goals:Experimental Goals:

pp

ee--KK--

KK--

pp

Electronic hydrogenElectronic hydrogen KaonicKaonic hydrogenhydrogen

n=25n=25

n=2n=2

n=1n=1

2p2p-->1s (K>1s (K))X ray of interestX ray of interest

n=1n=1

HydrogenHydrogenatomatom

pp

ee--KK--

KK--

pp

Electronic hydrogenElectronic hydrogen KaonicKaonic hydrogenhydrogen

n=25n=25

n=2n=2

n=1n=1

2p2p-->1s (K>1s (K))X ray of interestX ray of interest

n=1n=1

HydrogenHydrogenatomatom

Kaonic atomsKaonic atoms

s p d fs p d f

KKkeVkeV

= = EE2p2p1s1s

E1s}

E2p

nn

44

33

22

11

KK

Kaonic atomsKaonic atoms

Shift Shift and width and width of 1s state are of 1s state are related to real and imaginary part of s-related to real and imaginary part of s-wave scattering lenght: wave scattering lenght:

Neglecting isospin simmetry breaking Neglecting isospin simmetry breaking corrections, we can write the Deser-corrections, we can write the Deser-Trueman relations [1] for kaonic Trueman relations [1] for kaonic hydrogen and deuterium:hydrogen and deuterium:

pKa

dKfmeV

dK

pKfmeV

pK

aai

aai

60122

41222

23

23

Scattering lenghts can be written in terms of the Scattering lenghts can be written in terms of the

ISOSPIN-DEPENDENT scattering lenghts:ISOSPIN-DEPENDENT scattering lenghts:

Caam

mma

IaIaa

KmN

KNdK

pK

)3(2

12

)1()0(

01

2

10

This term includes contributes due to 3 body problemThis term includes contributes due to 3 body problem

and it can be numerically calculatedand it can be numerically calculated

[1] S.Deser et al., Phys.Rev. 96 (1954) 774;[1] S.Deser et al., Phys.Rev. 96 (1954) 774;

T.L.Truemann, Nucl. Phys. 26 (1961) 57;T.L.Truemann, Nucl. Phys. 26 (1961) 57;

A.Deloff, Phys. Rev. C13 (1976) 730.A.Deloff, Phys. Rev. C13 (1976) 730.

Why SIDDHARTA?Why SIDDHARTA?

Scientific aims: Scientific aims: Scattering lenghts calculations Scattering lenghts calculations

Useful in understanding:Useful in understanding:

Chiral simmetry breaking mechanismChiral simmetry breaking mechanism Strange content of nucleonsStrange content of nucleons

DEAR ResultsDEAR Results

eVsyststat

eVsyststat

.)(39.)(111249

.)(6.)(37193

Results lead to a repulsive character of the interaction.Results lead to a repulsive character of the interaction.

((Phys. Rev. Lett. Phys. Rev. Lett. 9494, 212302 (2005) ), 212302 (2005) )

No deuterium measurement was achived, due to the too highNo deuterium measurement was achived, due to the too high

DAFNE background!!! DAFNE background!!!

Background reduction is needed!Background reduction is needed! SIDDHARTASIDDHARTA

Most precise measurement up to now!Most precise measurement up to now!

Background in DAFNEBackground in DAFNE

SYNCHRONOUS: It’s associated to K production, wich means SYNCHRONOUS: It’s associated to K production, wich means decaysdecays

It can be considered an hadronic backgroundIt can be considered an hadronic background

ASYNCHRONOUS: It’s dued to final products of electromagnatic cascade wich is produced in DAFNEASYNCHRONOUS: It’s dued to final products of electromagnatic cascade wich is produced in DAFNE

and to other materials wich are in the setup and that are activates from particle lost from the beam. and to other materials wich are in the setup and that are activates from particle lost from the beam.

It is also dued to Touschek effect (interaction between particles of the same bunch)It is also dued to Touschek effect (interaction between particles of the same bunch)

The main contribute is the asynchronous one The main contribute is the asynchronous one

wich can be reducted using a trigger.wich can be reducted using a trigger.

DEAR detectors were CCD (Sylicon Pixel Type), DEAR detectors were CCD (Sylicon Pixel Type),

Non triggerable (too slow)Non triggerable (too slow)

In order to measure shift and width of kaonic hydrogen and deuterium KIn order to measure shift and width of kaonic hydrogen and deuterium K line with a fewline with a few eV precision, we need a S/B ratio near unity. DEAR case eV precision, we need a S/B ratio near unity. DEAR case was~ 1/70was~ 1/70

Silicon Drift DetectorsSilicon Drift Detectors : :

-- High efficiency in a wide energy range (from few hundreds eV to 15 KeV)High efficiency in a wide energy range (from few hundreds eV to 15 KeV)

- - Good energy resoultion, (~150 eV at 110 K at 6 keV )Good energy resoultion, (~150 eV at 110 K at 6 keV ) - Big surface (~cm- Big surface (~cm22), wich provide big detected areas with few front end channels), wich provide big detected areas with few front end channels- High rates capability- High rates capability

- - Very fast reading, wich means triggerabilityVery fast reading, wich means triggerability

SIDDHARTASIDDHARTA and SDDs and SDDs

SDDSDDAn electric field leads electrons, generated by particle flow (x-Rays or ionizing) to a small collector anode. At the same time holes are immediately removed from electron’s path by cathode strips.

First time used as spectroscopy (energy) detectors! First time used as spectroscopy (energy) detectors!

Designed for this experimentDesigned for this experiment

DetectorsDetectors

Target cellTarget cell

Cell is made of Kapton, a plastic material with no elements

witch could have transition lines near 6 KeV

Trigger systemTrigger system The trigger system has to The trigger system has to

provide the DAQ start and provide the DAQ start and monitorize Kaon flux wich enter monitorize Kaon flux wich enter the setupthe setup

Kaon produced in back to back Kaon produced in back to back configurationconfiguration

Day-One Setup on DAFNE, 22 Jan. Day-One Setup on DAFNE, 22 Jan. 20082008

SIDDHARTA SetupSIDDHARTA Setup

SIDDHARTA

Kaon monitor

lead shield

DAY1 SetupDAY1 Setup

DAY1 SetupDAY1 Setup

DAY1 SetupDAY1 Setup

Before installing the detector and target system

Installation of SIDDHARTA into final frame

Installing cables and SDD detector

signal and bus cables

HV + LV distribution board

SDDs with pre-amplifierboard

Working group

Day-One setupDay-One setup

Tuning of setup / Tuning of setup / optimisationoptimisation 100 pb100 pb-1-1

Precision measurement of kaonic hydrogenPrecision measurement of kaonic hydrogen 400 pb400 pb-1-1

(at the percent level)(at the percent level)

Measurement of kaonic deuteriumMeasurement of kaonic deuterium 600 pb600 pb-1-1

(first measurement)(first measurement)

Further options:Further options:

Additional kaonic deuterium measurementAdditional kaonic deuterium measurement

Kaonic helium studies (Kaonic helium studies (33He and He and 44He)He)

other light kaonic atoms e.g. Li, Be…other light kaonic atoms e.g. Li, Be…

Beam time requestBeam time request