Nonmesonic weak decay spectra of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mmultiscripts><mml:mtext>He</mml:mtext><mml:mprescripts /><mml:mi>Λ</mml:mi><mml:mrow><mml:mspace width="0.2em" /><mml:mn>4</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>

Bauer, E.; Galeão, A. P.; Hussein, M. S.; Krmpotić, F.; Parker, Joseph D.

doi:10.1016/j.physletb.2009.01.072

Cited by 12 publications

(37 citation statements)

References 37 publications

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“…In the evaluation of Γ N M , and the corresponding spectra, are used the Shell Model (SM) and the Fermi Gas Model (FGM) for Γ 1 (within the two-particle phase space) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][20][21][22][23], while for Γ 2 (within the three-particle phase space) only the later model has been employed so far [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…More, we will seize the opportunity to discuss the spectra of other two light hypernuclei, namely of 4 Λ H, and 5 Λ He, taking care of measurements done on the latter at KEK [32][33][34], and FINUDA [36]. Theoretical expressions for different NM weak decay spectra within the IPSM that are used here have been presented previously [10,[25][26][27][28][29] and will not be repeated here.…”

Section: Introductionmentioning

confidence: 99%

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Nonmesonic Weak Decay Spectra of Light Hypernuclei

Krmpotić

2014

Few-Body Syst

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The nonmesonic weak decay spectra of light hypernuclei have been evaluated in a systematic way. As theoretical framework we adopt the independent particle shell model with three different one-meson-exchange transition potentials. Good agreement with data is obtained for proton and neutron kinetic energy spectra of 4 Λ He, and 5 Λ He, when the recoil effect is considered. The coincidence spectra of proton-neutron pairs are also accounted for quite reasonably, but it was not possible to reproduce the data for the neutron-neutron pair spectra. It is suggested that the π + K meson-exchange model with soft monopole form factors could be a good starting point for describing the dynamics responsible for the decays of these two hypernuclei. The 4 Λ H spectra are also presented.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nonmesonic Weak Decay Spectra of Light Hypernuclei

Krmpotić

2014

Few-Body Syst

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“…In summary, the theory reproduces correctly the shapes of all spectra at medium and high energies (E p > ∼ 40 MeV), but it overestimates to a great extent their magnitudes, when is used the full OME model PSVE with standard parametrization. The agreement is much improved when is employed the SPKE model, i.e., the same model which reproduces satisfactorily the NM decays rates Γ p and Γ n of the s-shell hypernuclei [1].…”

mentioning

confidence: 79%

“…It is based on the original idea of Yukawa that the NN interaction at long distance is due to the one-pion-exchange (OPE), the dominant role being played by the exchange of pion and kaon mesons. Our present study involves the transition probability densities S N that can be obtained from the differentiation of the decay rates Γ N [1,2], and have been measured at the KEK [3], BNL [4], and FINUDA [5]. They are: 1) the single-proton spectra S p (E), and total neutron spectra S nt (E) = 2S p (E) + S n (E), as a function of corresponding one-nucleon kinetic energies E N , and 2) two-particle-coincidence spectra, as a function of: i) the sum of kinetic energies E n + E N ≡ E nN , S nN (E), ii) the opening angle θ nN , S nN (cos θ ), and iii) the center of mass (c.m.)…”

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confidence: 99%

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Dynamics of hypernuclear nonmesonic weak decay

Krmpotić¹,

Deppman²,

Conti³

2012

AIP Conference Proceedings

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Abstract. Simple and coincidence spectra of the NM weak decay of light hypernuclei have been evaluated in a systematic way for the first time. We have only considered 1N induced processes, neglecting entirely the events induced by 2N emission, as well as the effects of the FSIt's. As the theoretical framework we have used the IPSM with three different parametrizations for the transition potential. The comparison with data strongly suggests that the soft π + K exchange model could be a good starting point to describe the dynamics in the NM weak decays of s-and p-shell hypernuclei.Keywords: nonmesonic weak decay; one-meson-exchange: independent-particle shell model PACS: 21.80.+a, 13.75.Ev, 27.10.+hThe Λ-hypernuclei are mainly produced by the (K − , p − ) and the (p + , K + ) strong reactions, and disintegrate by the weak decay with the ratewhere Γ M is decay rate for the mesonic (M) decay Λ → πN, and Γ NM is the rate for the nonmesonic (NM) decay, which can be induced either by one bound nucleon (1N), Γ 1 (ΛN → nN), or by two bound nucleons (2N), Γ 2 (ΛNN → nNN), where N = p, n i.e.,In both cases the mass is changed by 176 MeV, and the strangeness by ΔS = −1, which makes the NM weak process to be the most radical modification of an elementary particle within the nuclear envarment, and offers the best opportunity to scrutinize the strangeness-changing force between hadrons. On the other hand, the hypernuclear physics leads to the extension of the radioactivity domain to three dimensions (N, Z, S), which, because of the additional binding due to the Λ-hyperon, modifies the neutron drip line, and is even richer in elements than the ordinary (N, Z) domain. (For instance, while the one-neutron separation energy in 20 C is 1.01 MeV, it is 1.63 MeV in 21 Λ C, and 6 Λ He is bound while 5 He is unbound.) Because of this glue attribute of hypernuclei the ΛN interaction is closely related to the inquiry on the existence of strange quark matter and its fragments, and strange stars (analogues of neutron stars), which makes the NM decay also relevant for astrophysics and cosmology. The schematic representation of the two decay channels, when the pertinent dynamics is described by OME potentials, is shown in Fig. 1. This is the most frequently used Nuclear Structure and Dynamics 2012

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Weak nonmesonic decay spectra of hypernuclei

et al. 2010

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We compute one-and two-nucleon kinetic-energy spectra and opening-angle distributions for the nonmesonic weak decay of several hypernuclei, and compare our results with some recent data. The decay dynamics is described by transition potentials of the one-meson-exchange type, and the nuclear structure aspects by two versions of the independent-particle shell model (IPSM). In version IPSM-a, the hole states are treated as stationary, while in version IPSM-b the deep-hole ones are considered to be quasistationary and are described by Breit-Wigner distributions.The mesonic mode, Λ → Nπ, with a rather small Q-value,MeV, is heavily inhibited for Λ-hypernuclei, except for the very lightest, due to Pauli blocking. With increasing mass number, A, a new mode quickly becomes dominant, namely the nonmesonic weak decay (NMWD), ΛN → nN, whose Q-value, Q N M = M Λ − M N + ε Λ + ε N ≈ 120 -135 MeV, is sufficiently large to render this Pauli blocking less and less effective. NMWD can be seen as one of the most radical transmutations of an elementary particle inside the nuclear medium: the strangeness is changed by ∆S = −1 and the mass by ∆M = M Λ − M N = 176 Mev. From a practical point of view, the main interest in NMWD is that it is, at present, the only way available to probe the strangeness-changing interaction between baryons.Lately, the quality of experimental data on NMWD has improved considerably, and today one has available, not only one-nucleon kinetic energy spectra, but also twonucleon coincidence spectra and opening-angle distributions obtained in several laboratories around the world, such as, KEK, FINUDA, and BNL. Here we briefly discuss a simple but fully quantum-mechanical formalism for the theoretical investigation of these observables. For more details see Refs.[1] and [2

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Nonmesonic weak decay spectra of HeΛ4

Cited by 12 publications

References 37 publications

Nonmesonic Weak Decay Spectra of Light Hypernuclei

Nonmesonic Weak Decay Spectra of Light Hypernuclei

Dynamics of hypernuclear nonmesonic weak decay

Weak nonmesonic decay spectra of hypernuclei

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