Spectra of charmed and bottom baryons with hyperfine interaction

Wang, Zhenyang; Qi, Jing-Juan; Guo, Xin-Heng; Wei, Ke-Wei

doi:10.1088/1674-1137/41/9/093103

Cited by 19 publications

(12 citation statements)

References 33 publications

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“…Predictions of ∼ 3000 ± 40 MeV for the negative-parity Ω c states, and an analogous range for the Ω b states, have been made by several authors [10,[15][16][17][18][19][20][21][22][23][24][25][26][27]. (The last paper treats only 2S levels, identifying the states at 3066, 3119 MeV as candidates for J P = 1/2 + , 3/2 + , respectively.…”

Section: Alternative Interpretationsmentioning

confidence: 88%

Very narrow excited Ωc baryons

2017

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Recently LHCb reported the discovery of five extremely narrow excited Ω c baryons decaying into Ξ + c K − . We interpret these baryons as bound states of a c-quark and a P -wave ss-diquark. For such a system there are exactly five possible combinations of spin and orbital angular momentum. The narrowness of the states could be a signal that it is hard to pull apart the two s-quarks in a diquark. We predict two of spin 1/2, two of spin 3/2, and one of spin 5/2, all with negative parity. Of the five states two can decay in S-wave and three can decay in D-wave. Some of the D-wave states might be narrower than the S-wave states. We discuss relations among the five masses expected in the quark model and the likely spin assignments and compare with the data. A similar pattern is expected for negative-parity excited Ω b states. An alternative interpretation is noted in which the heaviest two states are 2S excitations with J P = 1/2 + and 3/2 + , while the lightest three are those with J P = 3/2 − , 3/2 − , 5/2 − expected to decay via D-waves. In this case we expect J P = 1/2 − Ω c states around 2904 and 2978 MeV.PACS codes: 12.39. Jh, 13.20.Jf, 13.25.Jx, 14.40 The proposed values of spin-parity J P are ours. An alternative set of assignments is shown in parentheses.State Mass (MeV) a Width (MeV) Proposed J P Ω c (3000) 0 3000.4 ± 0.2 ± 0.1 4.5 ± 0.6 ± 0.3 1/2 − (3/2 − ) Ω c (3050) 0 3050.2 ± 0.1 ± 0.1 0.8 ± 0.2 ± 0.1 1/2 − (3/2 − ) < 1.2 MeV, 95% CL Ω c (3066) 0 3065.6 ± 0.1 ± 0.3 3.5 ± 0.4 ± 0.2 3/2 − (5/2 − ) Ω c (3090) 0 3090.2 ± 0.3 ± 0.5 8.7 ± 1.0 ± 0.8 3/2 − (1/2 + ) Ω c (3119) 0 3119.1 ± 0.3 ± 0.91.1 ± 0.8 ± 0.4 5/2 − (3/2 + ) < 2.6 MeV, 95% CL a Additional common error of +0.3,-0.5 MeV from M (Ξ + c ) uncertainty. I IntroductionVery recently LHCb reported the discovery of five extremely narrow excited Ω c baryons decaying into Ξ + c K − [1], with masses and widths shown in Table I. We quote also our favored spin-parity assignment for these states, which we shall choose among the 5! = 120 possible permutations if all five states are P -wave excitations of the ss diquark with respect to the charmed quark. Some more recent calculations [2-6] that appeared after the first version of this paper reach the same conclusion. In parentheses we note an alternative assignment if the two heaviest states are 2S excitations.This discovery raises some immediate questions, which we address in detail: In Sec. II we comment on P -wave css baryons. We then analyze spin-dependent forces for the css system in Sec. III, building upon similar results [7] obtained previously for the negative-parity Σ c states. We evaluate the energy cost for a P -wave css excitation in Sec. IV, carry our results over to the Ω b system in Sec. V, discuss alternative interpretations of the spectrum in Sec. VI, and conclude in Sec. VII. Details of calculating the spin-dependent mass shifts are presented in Appendix A, with a linearized approximation in Appendix B.II P -wave c(ss) system Consider the (ss) in c(ss) to be an S-wave color3 c diquark....

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Section: Alternative Interpretationsmentioning

confidence: 88%

Very narrow excited Ωc baryons

2017

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“…Three such isodoublets, which are neither radially nor orbitally excited, should exist [4], and include one with spin j qs ¼ 0 and J P ¼ ð1=2Þ þ (Ξ b ), a second with j qs ¼ 1 and [5][6][7]. Beyond these lowest-lying states, a spectrum of heavier states is expected [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], where there are either radial or orbital excitations amongst the constituent quarks. The only such states discovered thus far in the b-baryon sector are the Λ b ð5912Þ 0 and Λ b ð5920Þ 0 resonances [24], which are consistent with being orbital excitations of the Λ 0 b baryon.…”

mentioning

confidence: 99%

“…− state [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. As there are several excited Ξ − b states expected in this mass region, the presence of more than one of these states contributing to this peak cannot be excluded.…”

mentioning

confidence: 99%

Observation of a New Ξb− Resonance

Aaij¹,

Adeva²,

Adinolfi³

et al. 2018

Phys. Rev. Lett.

108

112

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From samples of pp collision data collected by the LHCb experiment at ffiffi ffi s p ¼ 7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5 fb −1 , respectively, a peak in both the Λ In the constituent quark model [1,2], baryonic states form multiplets according to the symmetry of their flavor, spin, and spatial wave functions. The masses, widths, and decay modes of these states give insight into their internal structure [3]. The Ξ − mass or width determination, as they have larger systematic uncertainties due to modeling of the mass resolution.The LHCb detector [25,26] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks [25,26]. Events are selected online by a trigger, which consists of a hardware stage, based on information from the calorimeter and muon systems, followed by a software stage, which applies a full event reconstruction [27,28].

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“…The body mass index (BMI) was calculated as bodyweight (kg) divided by the square of the height (m 2 ). Because it was difficult to obtain the height and bodyweight data of large numbers of normal healthy people, we used data from previous studies on the physical development of adolescents aged 16–18 years in our city [21,22]. Therefore, in this study, we compared the height, bodyweight, and BMI of patients from 16–18 years with the control.…”

Section: Methodsmentioning

confidence: 99%

A Retrospective Case-Control Study on the Chest Wall and Lung Characteristics in Patients with Primary Spontaneous Pneumothorax

et al. 2019

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BackgroundPrimary spontaneous pneumothorax (PSP) is reported to be more common in young men who are thin and tall. This retrospective study aimed to analyze the clinical and chest wall characteristics associated with PSP.Material/MethodsBetween January 2008 to December 2017, the clinical and imaging data of 99 patients at first presentation with PSP were compared with 82 age-matched healthy controls. Computed tomography (CT) imaging was used to measure the anteroposterior and transverse diameters of the chest at four levels, including the aortic arch, tracheal bifurcation, right inferior pulmonary vein, and lower sternal edge. Chest deformity was calculated as the ratio of the transverse diameter of the hemithorax divided by anteroposterior diameter. Lung volume and average lung density of 32 cases with PSP were measured and compared with 10 patients without PSP. Intrapleural pressure of 43 cases PSP who were treated with a closed chest drain was measured and compared with 39 patients with mediastinal tumor who underwent thoracoscopic surgery.ResultsPatients with PSP showed a normal age distribution with a median of 17–18 years. The patients with PSP had significantly reduced anteroposterior and transverse diameters of the chest when compared with controls at four levels on CT (p<0.01). The lung volumes in patients with PSP were significantly reduced when compared with the controls (p<0.05), as were the minimum intrapleural pressure and pressure difference (p<0.05).ConclusionsThe findings support that chest wall dimensions may be associated with lung development, which are contributing factors in PSP.

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Spectra of charmed and bottom baryons with hyperfine interaction

Cited by 19 publications

References 33 publications

Very narrow excited Ωc baryons

Very narrow excited Ωc baryons

Observation of a New Ξb− Resonance

A Retrospective Case-Control Study on the Chest Wall and Lung Characteristics in Patients with Primary Spontaneous Pneumothorax

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