Kaonic nuclear clusters with ALICE

E. FragiacomoINFN Trieste

Convegno Nazionale sulla Fisica di ALICEVietri sul Mare – 30 maggio 2006

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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

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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

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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

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How do KNC decay

(1116) in coincidence with nucleons

No (1405) Invariant mass

analysis of the decay products used to reconstruct KNC’s

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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)

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Experimental results

E471@KEK FINUDA@DANE

Suzuki et al, ibidem Agnello et al., ibidem = 70 MeV ->

= 10-23 sec ~ 3 fm/c

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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)

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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

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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)