dorsal/arxiv
View SchemaThe role of five-quark components in gamma decay of the $\Delta(1232)$
| Authors | Q. B. Li, D. O. Riska |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0511053 |
| URL | https://arxiv.org/abs/nucl-th/0511053 |
| DOI | 10.1016/j.nuclphysa.2005.11.020 |
| Journal | Nucl.Phys. A766 (2006) 172-182 |
Abstract
An admixture of 10-20 % of qqqq\bar q components in the Delta(1232) resonance is shown to reduce the well known underprediction for the decay width for Delta(1232)->N gamma decay by about half and that of the corresponding helicity amplitudes from a factor ~ 1.7 to ~ 1.5. The main effect is due to the quark-antiquark annihilation transitions qqqq\bar q -> qqq gamma, the consideration of which brings the ratio A_{3/2}/A_{1/2} and consequently the E2/M1 ratio R_{EM} into agreement with the empirical value. Transitions between qqqq\bar q components in the resonance and the nucleon qqqq\bar q->qqqq\bar q gamma are shown to enhance the calculated width by only a few percent, as long as the probability of the qqqq\bar q component of the Delta(1232) and the proton is at most ~ 20 %. The transitions qqqq\bar q->qqqq\bar q gamma between the qqqq\bar q components in the Delta(1232) and the proton do not lead to a nonzero value for R_{EM}.
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"abstract": "An admixture of 10-20 % of qqqq\\bar q components in the Delta(1232) resonance\nis shown to reduce the well known underprediction for the decay width for\nDelta(1232)-\u003eN gamma decay by about half and that of the corresponding helicity\namplitudes from a factor ~ 1.7 to ~ 1.5. The main effect is due to the\nquark-antiquark annihilation transitions qqqq\\bar q -\u003e qqq gamma, the\nconsideration of which brings the ratio A_{3/2}/A_{1/2} and consequently the\nE2/M1 ratio R_{EM} into agreement with the empirical value. Transitions between\nqqqq\\bar q components in the resonance and the nucleon qqqq\\bar q-\u003eqqqq\\bar q\ngamma are shown to enhance the calculated width by only a few percent, as long\nas the probability of the qqqq\\bar q component of the Delta(1232) and the\nproton is at most ~ 20 %. The transitions qqqq\\bar q-\u003eqqqq\\bar q gamma between\nthe qqqq\\bar q components in the Delta(1232) and the proton do not lead to a\nnonzero value for R_{EM}.",
"arxiv_id": "nucl-th/0511053",
"authors": [
"Q. B. Li",
"D. O. Riska"
],
"categories": [
"nucl-th"
],
"doi": "10.1016/j.nuclphysa.2005.11.020",
"journal_ref": "Nucl.Phys. A766 (2006) 172-182",
"title": "The role of five-quark components in gamma decay of the $\\Delta(1232)$",
"url": "https://arxiv.org/abs/nucl-th/0511053"
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