B meson decay constants f B c $$ {f}_{B_c} $$ , f B s $$ {f}_{B_s} $$ and f B from QCD sum rules

The B + c family of (cb) mesons with beauty and charm is of special interest among heavy quarkonium systems. The B + c mesons are intermediate between (cc) and (bb) states both in mass and size, so many features of the (cb) spectrum can be inferred from what we know of the charmonium and bottomonium systems. The unequal quark masses mean that the dynamics may be richer than a simple interpolation would imply, in part because the charmed quark moves faster in Bc than in the J/ψ. Close examination of the B + c spectrum can test our understanding of the interactions between heavy quarks and antiquarks and may reveal where approximations break down.Whereas the J/ψ and Υ levels that lie below flavor threshold are metastable with respect to strong decays, the Bc ground state is absolutely stable against strong or electromagnetic decays. Its dominant weak decays arise fromb →cW + , c → sW + , and cb → W + transitions, where W designates a virtual weak boson. Prominent examples of the first category are quarkonium transmutations such as B + c → J/ψ π + and B + c → J/ψ + ν , where J/ψ designates the (cc) 1S level. The high data rates and extraordinarily capable detectors at the Large Hadron Collider give renewed impetus to the study of mesons with beauty and charm. Motivated by the recent experimental searches for the radially excited Bc states, we update the expectations for the low-lying spectrum of the Bc system. We make use of lattice QCD results, a novel treatment of spin splittings, and an improved quarkonium potential to obtain detailed predictions for masses and decays. We suggest promising modes in which to observe excited states at the LHC. The 3P and 3S states, which lie close to or just above the threshold for strong decays, may provide new insights into the mixing between quarkonium bound states and nearby two-body open-flavor channels. Searches in the B ( * ) D ( * ) final states could well reveal narrow resonances in the J P = 0 − , 1 − , and 2 + channels and possibly in the J P = 0 + and 1 + channels at threshold.Looking further ahead, the prospect of very-high-luminosity e + e − colliders capable of producing tera-Z samples raises the possibility of investigating Bc spectroscopy and rare decays in a controlled environment.

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“…The same calculation yields f B * c /f Bc = 0.988 ± 0.027. A calculation in the framework of QCD sum rules gives f Bc = 528 ± 19 MeV [44].…”

Section: B Hadronic Transitionsmentioning

confidence: 99%

Mesons with beauty and charm: New horizons in spectroscopy

Eichten

Quigg

2019

Phys. Rev. D

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“…Constant (MeV) this work Lattice [3,4] QCD sum rules [22,23] LFQM [24] CCQM [25] BSE [27] for pseudoscalar (P ) and vector (V ) states, respectively. Here p is the momentum of the meson, and e µ λ is the polarization vector:…”

Section: Decay Constantsmentioning

confidence: 99%

“…We present a survey of recent work in TABLE III along with results from Lattice [3,4] and other approaches (see Refs. [22][23][24][25][26][27]) for comparison. Lattice results are systematically smaller than the other methods by about 20%, as also discussed in other references (e.g.…”

Section: Decay Constantsmentioning

confidence: 99%

Bc mesons and their properties on the light front

Tang

Maris

et al. 2018

Phys. Rev. D

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We investigate the unequal mass relativistic bound state system, the B c mesons, in a lightfront Hamiltonian formalism. We adopt an effective Hamiltonian based on soft-wall lightfront holography, together with a longitudinal confinement that was first introduced for heavy quarkonium. We also include the one gluon-exchange interaction with a running coupling, which produces the spin structure. We present the mass spectrum and light-front wave functions. We also use the light-front wave functions to calculate decay constants, charge and momentum densities, as well as distribution amplitudes. The results are compared with experiments and other theoretical approaches, all of which are in reasonable agreement. * tang@iastate.edu arXiv:1810.05971v3 [nucl-th]

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“…Apart from the standard information it contains also the decay constant f Bc of the B c meson, for which we utilize its value derived in the context of the sum rule method in Ref. [47].…”

Section: Mass and Meson-current Couplingmentioning

confidence: 99%

Open charm-bottom scalar tetraquarks and their strong decays

2017

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The mass and meson-current coupling of the diquark-antidiquark states with the quantum numbers J P = 0 + and quark contents Zq = [cq] [bq] and Zs = [cs][bs] are calculated using two-point QCD sum rule approach. In calculations the quark, gluon and mixing condensates up to eight dimensions are taken into account. The parameters of the scalar tetraquarks extracted from this analysis are employed to explore the strong vertices ZqBcπ, ZqBcη and ZsBcη and compute the couplings gZ q Bcπ , gZ q Bcη and gZ sBc η . The strong couplings are obtained within the soft-meson approximation of QCD light-cone sum rule method: they form, alongside with other parameters, the basis for evaluating the widths of Zq → Bcπ, Zq → Bcη and Zs → Bcη decays. Obtained in this work results for the mass of the tetraquarks Zq and Zs are compared with available predictions presented in the literature.

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B meson decay constants f B c $$ {f}_{B_c} $$ , f B s $$ {f}_{B_s} $$ and f B from QCD sum rules

Cited by 36 publications

References 62 publications

Mesons with beauty and charm: New horizons in spectroscopy

Mesons with beauty and charm: New horizons in spectroscopy

Bc mesons and their properties on the light front

Open charm-bottom scalar tetraquarks and their strong decays

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