neutron-neutron correlations in the dissociation of halo systems: 6 he

Neutron-Neutron Correlations in the Neutron-Neutron Correlations in the Dissociation of Halo Systems: Dissociation of Halo Systems: 66HeHe

Group Group ""ExotiquesExotiques" LPC-Caen" LPC-Caen

Collaboration LPC-CHARISSA-DEMONCollaboration LPC-CHARISSA-DEMON

• Motivation + HistoryMotivation + History

• Principles of neutron-neutron Principles of neutron-neutron

interferometryinterferometry

• 66He breakupHe breakup

• Limitations – coherence, theory…Limitations – coherence, theory…

• Conclusions & PerspectivesConclusions & Perspectives

Neutron-Neutron Correlations in the Neutron-Neutron Correlations in the Dissociation of Halo Systems: Dissociation of Halo Systems: 66HeHe

Jean-Luc Lecouey, Seminar““Borromean”Borromean”

Two-Neutron Halo Systems Two-Neutron Halo Systems

Jean-Luc Lecouey, Seminar

Two-Neutron Halo Systems Two-Neutron Halo Systems

n-n interaction in field of core binds n-n interaction in field of core binds the system ...the system ...

Jean-Luc Lecouey, Seminar

Two-Neutron Halo Systems Two-Neutron Halo Systems

Halo neutron correlationsHalo neutron correlations … ? … ?

rrnnnn

Jean-Luc Lecouey, Seminar

Halo n-n Spatial ConfigurationHalo n-n Spatial Configuration

RNBT Collaboration – 3-body FaddeevRNBT Collaboration – 3-body Faddeev

6He

““cigarcigar”” ““dineutrondineutron””

Jean-Luc Lecouey, Seminar

3-body Model Calculations 3-body Model Calculations ** : : 66He = He = + n +n + n +n

** Hagino, Sagawa, Phys Rev C72 (2005)Hagino, Sagawa, Phys Rev C72 (2005)

ground stateground state wavefunction wavefunction

rrc-nnc-nn = 3.6 fm = 3.6 fm ; rrnn nn = 4.6 fm= 4.6 fm

““dineutrondineutron””

““cigarcigar””

rr1 1 == rr2 2 =

Jean-Luc Lecouey, Seminar

A History of Probes …A History of Probes …

• dissociation:dissociation: p pcorecore v’s p v’s pnn [Hansen][Hansen]

• dissociation:dissociation: ppnnnn [Ieki [Ieki et alet al.].]

• very high Every high EBB dissociation: dissociation: -2n-2n v’s v’s -1n-1n [Bertsch [Bertsch et alet al.] .]

see also JA Tostevin see also JA Tostevin (today)(today)

• 2n transfer 2n transfer [Oganessian [Oganessian et alet al.] .]

see also T Roger, N Keeley see also T Roger, N Keeley (yesterday)(yesterday)

• radiative capture radiative capture [Sauvan [Sauvan et alet al.].]

• dissociation:dissociation: E1 strength + RE1 strength + Rrmsrms [Hagino, Sagawa][Hagino, Sagawa]

• RRrmsrms charge charge [Mueller [Mueller et alet al.].]

• …………

Jean-Luc Lecouey, Seminar

““That was the beginning, and the idea seemed so That was the beginning, and the idea seemed so

obvious to me and so elegant that I fell deeply in love obvious to me and so elegant that I fell deeply in love

with it. And, like falling in love with a woman, it is only with it. And, like falling in love with a woman, it is only

possible if you do not know much about her, so you possible if you do not know much about her, so you

cannot see her faults. The faults will become apparent cannot see her faults. The faults will become apparent

later, but after the love is strong enough to hold you to later, but after the love is strong enough to hold you to

her."her."

Richard FeynmanRichard Feynman

Nobel Lecture Nobel Lecture (1965)(1965)

Jean-Luc Lecouey, Seminar

Intensity Interferometry - HBT EffectIntensity Interferometry - HBT Effect** : : Source SizeSource Size

FM Marqués et al., PLB (2000)FM Marqués et al., PLB (2000)

Correlation Function - CCorrelation Function - Cnnnn

CCnn nn dominated dominated by n-n FSIby n-n FSI ** incoherentincoherent emission emission

Jean-Luc Lecouey, Seminar

CCnnnn(r,t) : r(r,t) : r00 = 3 fm= 3 fm ; ; = 0, 100, 300*, 1000 = 0, 100, 300*, 1000

fm/cfm/c

Group Exotiques - G. Normand Group Exotiques - G. Normand et al.et al.

* * 55HeHegsgs ~ 0.7 MeV~ 0.7 MeV

Jean-Luc Lecouey, Seminar

3-Body Breakup: 3-Body Breakup: ““Complete KinematicsComplete Kinematics””

Target

vcore

v0

ppn-nn-n = p = pn1 n1 - p- pn2n2

EErelrel = = (v(vcorecore- v- vnnnn))22/2/2

vn2

vn1

Jean-Luc Lecouey, Seminar

Intensity Interferometry - HBT EffectIntensity Interferometry - HBT Effect

U. of Sydney Stellar Interferometer, Narrabri, NSWU. of Sydney Stellar Interferometer, Narrabri, NSW

““Hanbury-Brown’s Steamroller“ D Kleppner, Physics Today, August 2008Hanbury-Brown’s Steamroller“ D Kleppner, Physics Today, August 2008

Jean-Luc Lecouey, Seminar + + Cross-talk RejectionCross-talk Rejection !! !!

DEMONDEMON

90 modules (NE213) 90 modules (NE213)

ToF & positionToF & position

nn ~ 10% ~ 10% nnnn ~ 1% ~ 1%

Setup: Kinematically “CompleteSetup: Kinematically “Complete”” MeasurementMeasurement

FM Marqués FM Marqués et al.,et al., NIMA450 (2000) NIMA450 (2000)

Jean-Luc Lecouey, Seminar

n-n Separation : EMD + Cn-n Separation : EMD + Cnnnn + + Gaussian SourceGaussian Source**

Event mixing – residual Event mixing – residual correlationscorrelations FM Marqués FM Marqués et al.,et al., PLB (2000) PLB (2000)

* * R Lednicky, VL Lyuboshits, Yad. Fiz. R Lednicky, VL Lyuboshits, Yad. Fiz. (1982)(1982)

Jean-Luc Lecouey, Seminar

CC//Pb(Pb(66He,He,+n+n)X +n+n)X @@ 30 30 MeV/uMeV/u : C : Cnnnn + + Gaussian SourceGaussian Source

** **

** r rnnnn average of n-n configurations of average of n-n configurations of 66He He breakup statesbreakup states

Group Exotiques - G. Normand Group Exotiques - G. Normand et al.et al.

Jean-Luc Lecouey, SeminarGroup Exotiques - G. Normand Group Exotiques - G. Normand et al.et al.

CC//Pb(Pb(66He,He,+n+n)X +n+n)X @@ 30 30 MeV/nucleonMeV/nucleon

22++

22++ ((11--,, …… ) )

Jean-Luc Lecouey, SeminarGroupe Exotiques - G. Normand Groupe Exotiques - G. Normand et al.et al.

CC//Pb(Pb(66He,He,+n+n)X +n+n)X @@ 30 30 MeV/nucleonMeV/nucleon

22++ 22++

EEdd((66He) after He) after subtractionsubtraction of uncorrelated distribution of uncorrelated distribution

Jean-Luc Lecouey, Seminar

Three-body continuum spatial correlations in Three-body continuum spatial correlations in 66He He **

** B Danilin B Danilin et al.,et al., PRC69 (2004) PRC69 (2004)

Jean-Luc Lecouey, Seminar

Effects of a coherent n-n source Effects of a coherent n-n source **

* * Yamashita et al., PRC72 (2005), NUPA735 (2004)Yamashita et al., PRC72 (2005), NUPA735 (2004)

[ Data: FMM et al. PLB (2000) ] [ Data: FMM et al. PLB (2000) ]

Conclusions & PerspectivesConclusions & Perspectives

Neutron-neutron correlations …Neutron-neutron correlations …

• breakup + “interferometry˝ (Cbreakup + “interferometry˝ (Cnnnn) as a possible tool ) as a possible tool

to explore halo n-n correlations in to explore halo n-n correlations in unbound unbound

Ex/continuumEx/continuum

Improvements …Improvements …

• First stepFirst step : account for : account for coherencecoherence in emission in emission

• IdeallyIdeally : realistic structure + reaction + FSI to : realistic structure + reaction + FSI to

generate pgenerate pnnnn, , CCnnnn,, ppcorecore, d, d/dE/dE, …, …

Jean-Luc Lecouey, SeminarH Esbensen H Esbensen et al.,et al., PRC48 (1993) PRC48 (1993)

Pb(Pb(1111Li,Li,99Li+n+n)X Li+n+n)X @@ 28 28 MeV/nucleonMeV/nucleon

3-body model wave function3-body model wave function + EMD + FSI+ EMD + FSI (c-n et (c-n et nn)nn)

Jean-Luc Lecouey, Seminar

Jean-Luc Lecouey, Seminar

CC//Pb(Pb(66He,He,+n+n)X +n+n)X @@ 30 30 MeV/nucleonMeV/nucleon

Group Exotiques - G. Normand Group Exotiques - G. Normand et al.et al.

Jean-Luc Lecouey, SeminarGSI/LAND – T. Aumann GSI/LAND – T. Aumann et al.et al.

CC//Pb(Pb(66He,He,+n+n)X +n+n)X @@ 240240 MeV/nucleonMeV/nucleon