kaonic nuclear clusters with alice e. fragiacomo infn trieste convegno nazionale sulla fisica di...
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Kaonic nuclear clusters with ALICE
E. FragiacomoINFN Trieste
Convegno Nazionale sulla Fisica di ALICEVietri sul Mare – 30 maggio 2006
PWG2 - 23/05/06 Enrico Fragiacomo 2 of 14
Outline
Kaonic nuclear clusters (KNC)
Brief review on theoretical and experimental results
Perspectives in relativistic heavy ion collisions
Dynamical generation of the (1405)
Afterburner implementation of (1405) in AliRoot
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What are KNC
KNC are nuclear systems involving (K- or )
e.g. K-p, K-pp, ... (single clusters),
K-K-pp, K-ppn, ... (double clusters)
Large binding energies (E ~ 100 MeV)
High densities (up to 4-9 0)
In this realm, (1405) is the simplest KNC
(K-p system) and it is used as a doorway for heavier
(K-pp, K-ppp,…) clustering
0KK
KK
PWG2 - 23/05/06 Enrico Fragiacomo 4 of 14
From the theory point of view
Phenomenological approaches for the N interaction,
reproducing the N scattering data, kaonic hydrogen atom data
and the binding energy and decay width of the (1405)
T. Yamazaki and Y. Akaishi, Nucl. Phys. B535 (2002) Make use of phenomenological potentials.
Obtain very high densities
A. Doté et al., Phys. Lett. B590 (2004) Antisymmetrized Molecular Dynamics (AMD) method for light clusters
A. S. Ivanov et al., nucl-th/0512037Kaonic Nuclear Clustering
KK
PWG2 - 23/05/06 Enrico Fragiacomo 5 of 14
Nuclear densities in KNC
Yamazaki, Doté, Akaishi, nucl-th/0310085
3He density for
comparison
ppnK-
ppnK-K-
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KNC can be produced via: direct reactions, such as A(K-,n) or A(K-,N)
• E.g. K- “d” -> [K-pn] -> (1116)n cascade reactions:
• E.g on 4He:
p + “n” -> (1405) + K0 +p + “ppn” -> [pppK-] + n
(1116)pp Suggestions to identify clusters as residues
(“ fragments”) after relativistic heavy-ion collisions (Yamazaki, Doté, Akaishi, nucl-th/0310085)
How are KNC produced
KK
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Cascade production
Yamazaki, Doté, Akaishi, nucl-th/0310085
PWG2 - 23/05/06 Enrico Fragiacomo 8 of 14
How do KNC decay
(1116) in coincidence with nucleons
No (1405) Invariant mass
analysis of the decay products used to reconstruct KNC’s
PWG2 - 23/05/06 Enrico Fragiacomo 9 of 14
Experimental evidence
E471@KEK 4He(stopped K-,p)X Missing mass analysis
(see next slide) Strange tri-baryon S0(3115)
Suzuki et al, Phys Lett. B 597 (2004) 263
FINUDA@DANE A(stopped K-, p) Invariant mass analysis
(see next slide) K-pp decaying via p
Agnello et al., Phys. Rev. Lett. 94, 212303 (2005)
PWG2 - 23/05/06 Enrico Fragiacomo 10 of 14
Experimental results
E471@KEK FINUDA@DANE
Suzuki et al, ibidem Agnello et al., ibidem = 70 MeV ->
= 10-23 sec ~ 3 fm/c
PWG2 - 23/05/06 Enrico Fragiacomo 11 of 14
Dynamical generation of(1405)
E. Oset, A. Ramos,
Nucl. Phys. A635, 99 (1998)
UPT calculations for the
s-wave meson-nucleon
interaction in the S = -1 sector
Reproduces low-energy
experimental cross sections
E.g K-p -> K-p, -+ -> -+
Reproduces (1405) with one
free parameter only (cut-off)
PWG2 - 23/05/06 Enrico Fragiacomo 12 of 14
Oset’s model implemented in AliRoot (E. Cattaruzza and EF)
1. Loops over all K-p (or ) combinations from Pythia2. Calculates the interaction probability3. Selects the interacting pairs and the interaction channel
according to the probability4. Modifies the particle stack (work in progress) Next step: introduce nuclear matter ->
density dependence of in-medium N interaction (A .Ramos and E. Oset, nucl-th/9906016)
AliGenAfterBurnerOset
K
PWG2 - 23/05/06 Enrico Fragiacomo 13 of 14
Preliminary
M(GeV/c2)
En
trie
s
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Conclusions (milestones)
Join the forum on KNC (immediate)
Reconstruction of KNC’s (within end of year)
(e.g. (1405), K-pp -> (1116)p or
K-K-pp -> )
Nuclear matter implementation (within summer)
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