LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Analysis of Neutral B-Meson Decays into Two Muons. Phys. Rev. Lett., 128(4), 041801–13pp.
Abstract: The branching fraction B(B-s(0)->mu(+)mu(-)) = (3.09(-0.43-0.11)(+0.46+0.15)) x 10(-9) and the effective lifetime to tau(B-s(0) -> mu(+)mu(-)) = 2.07 +/- 0.29 +/- 0.03 ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B-0 ->mu(+)mu(-)gamma) and B-s(0)->mu(+)mu(-)gamma decays is found and upper limits B(B(B-0 ->mu(+)mu(-)) < 2.6 x 10(-10) and B(B-s(0) -> mu(+)mu(-)gamma) < 2.0 x 10(-9) at the 95% C.L. are determined, where the latter is limited to the range m(mu mu) > 4.9 GeV/c(2). The results are in agreement with the standard model expectations.Branching fraction and effective lifetime measurements of the rare decay B-s(0) -> mu(+)mu(-) and searches for the decays B-0 -> mu(+)mu(-) and B-s(0) -> mu(+)mu(-)gamma are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a luminosity of 9 fb(-1).
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Garcia Canal, C. A., Tarutina, T., & Vento, V. (2023). Analysis of Nuclear Effects in Structure Functions and Their Connection with the Binding Energy of Nuclei. Braz. J. Phys., 53(6), 161–8pp.
Abstract: We describe nuclear effects in structure functions of nuclei in DIS by means of a multiplicative factor beta(A)(x) which differentiates the structure function of the bound nucleons from that of the free nucleons. Our analysis determines that beta(A)(x) establishes a relation between the quark-gluon dynamics expressed by the bound nucleon structure functions and the nuclear dynamics as described by the well-known semi-empirical Bethe-Weizsacker mass formula. This relation corroborates a connection between the underlying quark-gluon dynamics and the phenomenological nuclear dynamics.
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Wang, E., Xie, J. J., Geng, L. S., & Oset, E. (2018). Analysis of the B+ -> J/Psi phi K+ data at low J/Psi phi invariant masses and the X(4140) and X(4160) resonances. Phys. Rev. D, 97(1), 014017–6pp.
Abstract: We have studied the J/Psi phi mass distribution of the B+ -> J/Psi phi K+ reaction from threshold to about 4250 MeV, and find that one needs the contribution of the X(4140) with a narrow width, together with the X(4160) which accounts for most of the strength of the distribution in that region. The existence of a clear cusp at the D-s*(D) over bar (s)* threshold indicates that the X(4160) resonance is strongly tied to the D-s*(D) over bar (s)* channel, which finds a natural interpretation in the molecular picture of this resonance.
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Wang, E., Liang, W. H., & Oset, E. (2021). Analysis of the e(+)e(-) -> J/psi D(D)over-bar reaction close to the threshold concerning claims of a chi(c0)(2P) state. Eur. Phys. J. A, 57(1), 38–9pp.
Abstract: We analyze the D (D) over bar mass distribution from a recent Belle experiment on the e(+)e(-) -> J/.D (D) over bar reaction, and show that the mass distribution divided by phase sp(c)e does not have a clear peak above the D (D) over bar threshold that justifies the experimental claim of chi(c0)(2P) state from those data. Then we use a unitary formalismwith coupled channels D+ D-, D-0 (D) over bar (0), D-s(D) over bar (s), and eta eta, with some of the interactions taken from a theoretical model, and use the data to fix other parameters. We then show that, given the poor quality of the data, we can get different fits leading to very different D (D) over bar amplitudes, some of them supporting a D (D) over bar bound state and others not. The main conclusion is that the claim for the chi(c0)(2P) state, already included in the PDG, is premature, but refined data can provide very valuable information on the D (D) over bar scattering amplitude. As side effects, we warn about the use of a Breit-Wigner amplitude parameterization close to threshold, and show that the D-s(D) over bar (s) channel plays an important role in this reaction.
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Wang, E., Li, H. S., Liang, W. H., & Oset, E. (2021). Analysis of the gamma gamma -> D(D)over-bar reaction and the D(D)over-bar bound state. Phys. Rev. D, 103(5), 054008–10pp.
Abstract: In this work, we investigate the reaction of gamma gamma -> D (D) over bar, taking into account the S-wave D (D) over bar final state interaction. By fitting to the D (D) over bar, invariant mass distributions measured by the Belle and BABAR Collaborations, we obtain a good reproduction of the data by means of a D (D) over bar, amplitude that produces a bound D (D) over bar, statewith isospin I = 0 close to threshold. The error bands of the fits indicate, however, that more precise data on this reaction are needed to be more assertive about the position and width of such a state.
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