کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8190163 | 1528852 | 2012 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
1ââ and 0++ heavy four-quark and molecule states in QCD
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موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک هسته ای و انرژی بالا
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چکیده انگلیسی
We estimate the masses of the 1ââ heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in αs but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50-110) MeV and the ones of about (250-300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavor independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Yc(4260,4360,4660) and Yb(10890)1ââ experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure1ââ four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0++ four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1ââ states, while the splittings between the 0++ lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1ââ and 0++ four-quark states which are tiny and which exhibit a 1/MQ behavior. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHCb and some other hadron factories.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics Letters B - Volume 715, Issues 1â3, 29 August 2012, Pages 129-141
Journal: Physics Letters B - Volume 715, Issues 1â3, 29 August 2012, Pages 129-141
نویسندگان
R.M. Albuquerque, F. Fanomezana, S. Narison, A. Rabemananjara,