scholarly journals Measurement of branching fractions of J/ψ and ψ(3686) decays to Σ+ and $$ \overline{\Sigma} $$−

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
M. Ablikim ◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
...  

Abstract Using 1310.6 × 106J/ψ and 448.1 × 106ψ(3686) events collected with the BESIII detector, the branching fractions of J/ψ decays to Σ+$$ \overline{\Sigma} $$ Σ ¯ − is measured to be (10.61 ± 0.04 ± 0.36) × 10−4, which is significantly more precise than the current world average. The branching fractions of ψ(3686) decays to Σ+$$ \overline{\Sigma} $$ Σ ¯ − is measured to be (2.52 ± 0.04 ± 0.09) × 10−4, which is consistent with the previous measurements. In addition, the ratio of $$ \mathcal{B} $$ B (ψ(3686) → Σ+$$ \overline{\Sigma} $$ Σ ¯ −)/$$ \mathcal{B} $$ B (J/ψ → Σ+$$ \overline{\Sigma} $$ Σ ¯ −) is determined to be (23.8 ± 1.1)% which violates the “12% rule”.

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
M. Ablikim ◽  
◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
...  

Abstract We measure the branching fractions for seven $$ {D}_s^{+} $$ D s + two-body decays to pseudo-scalar mesons, by analyzing data collected at $$ \sqrt{s} $$ s = 4.178 ∼ 4.226 GeV with the BESIII detector at the BEPCII collider. The branching fractions are determined to be$$ {\displaystyle \begin{array}{c}\mathcal{B}\left({D}_s^{+}\to {K}^{+}\eta \hbox{'}\right)=\left(2.68\pm 0.17\pm 0.17\pm 0.08\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to \eta \hbox{'}{\pi}^{+}\right)=\left(37.8\pm 0.4\pm 2.1\pm 1.2\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to {K}^{+}\eta \right)=\left(1.62\pm 0.10\pm 0.03\pm 0.05\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to \eta {\pi}^{+}\right)=\left(17.41\pm 0.18\pm 0.27\pm 0.54\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to {K}^{+}{K}_S^0\right)=\left(15.02\pm 0.10\pm 0.27\pm 0.47\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to {K}_S^0{\pi}^{+}\right)=\left(1.109\pm 0.034\pm 0.023\pm 0.035\right)\times {10}^{-3},\\ {}\mathcal{B}\left({D}_s^{+}\to {K}^{+}{\pi}^0\right)=\left(0.748\pm 0.049\pm 0.018\pm 0.035\right)\times {10}^{-3},\end{array}} $$ B D s + → K + η ' = 2.68 ± 0.17 ± 0.17 ± 0.08 × 10 − 3 , B D s + → η ' π + = 37.8 ± 0.4 ± 2.1 ± 1.2 × 10 − 3 , B D s + → K + η = 1.62 ± 0.10 ± 0.03 ± 0.05 × 10 − 3 , B D s + → η π + = 17.41 ± 0.18 ± 0.27 ± 0.54 × 10 − 3 , B D s + → K + K S 0 = 15.02 ± 0.10 ± 0.27 ± 0.47 × 10 − 3 , B D s + → K S 0 π + = 1.109 ± 0.034 ± 0.023 ± 0.035 × 10 − 3 , B D s + → K + π 0 = 0.748 ± 0.049 ± 0.018 ± 0.035 × 10 − 3 , where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode $$ {D}_s^{+} $$ D s + → K+K−π+. Precision of our measurements is significantly improved compared with that of the current world average values.


2019 ◽  
Author(s):  
Gabriel da Silva

Atmospheric oxidation of isoprene produces significant yields of eight unique nitrate 11 compounds, each with a β- or δ-hydroxy group. These isoprene hydroxy nitrates (ISOPNs) 12 significantly impact upon global NOx budgets, O3 levels, and aerosol formation. 13 Uncertainties exist, however, in our understanding of ISOPN chemistry, particularly in their 14 yields from the reaction of isoprene peroxyl radicals with NO. This study describes novel 15 isomerization reactions of the ISOPNs, identified through the application of computational 16 chemistry techniques. These reactions produce saturated polycyclic orthonitrite compounds 17 via attack of the R–NO2 group on the vinyl moiety. For the δ-hydroxy nitrates, low-energy 18 isomerization pathways exist to six-membered ring compounds that are around 5 kcal mol-1 19 exothermic. These reactions proceed with barriers around 15 kcal mol-1 below the 20 respective peroxyl radical + NO reactants and yield orthonitrites that can further isomerize 21 to β-hydroxy ISOPNs. Moreover, the δ-hydroxy nitrates can directly interconvert with their β 22 substituted counterparts via NO3 group migration, with barriers that are lower yet. It follows 23 that β-hydroxy nitrates may be stabilized in the δ-hydroxy form, and vice versa. Moreover, 24 the lowest-energy pathway for dissociation of the δ-hydroxy ISOPNs is for the formation of 25 β-hydroxy alkoxyl radicals, and because of this established branching fractions between the 26 various isoprene peroxyl radicals may require re-evaluation. The results presented here also 27 suggest that ISOPNs may be stabilized to some extent in their saturated orthonitrite forms, 28 which has implications for both the total nitrate yield and for their subsequent removal by 29 OH, O3, and photolysis.<br><br>


1982 ◽  
Vol 25 (11) ◽  
pp. 2869-2886 ◽  
Author(s):  
K. G. Hayes ◽  
M. L. Perl ◽  
M. S. Alam ◽  
A. M. Boyarski ◽  
M. Breidenbach ◽  
...  

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Linda M. Carpenter ◽  
Taylor Murphy ◽  
Matthew J. Smylie

Abstract In this work we study the collider phenomenology of color-octet scalars (sgluons) in minimal supersymmetric models endowed with a global continuous R symmetry. We systematically catalog the significant decay channels of scalar and pseudoscalar sgluons and identify novel features that are natural in these models. These include decays in nonstandard diboson channels, such as to a gluon and a photon; three-body decays with considerable branching fractions; and long-lived particles with displaced vertex signatures. We also discuss the single and pair production of these particles and show that they can evade existing constraints from the Large Hadron Collider, to varying extents, in large regions of reasonable parameter space. We find, for instance, that a 725 GeV scalar and a 350 GeV or lighter pseudoscalar can still be accommodated in realistic scenarios.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Decays of the 125 GeV Higgs boson into a Z boson and a ρ0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at $$ \sqrt{s} $$ s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb−1. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels.


2004 ◽  
Vol 70 (9) ◽  
Author(s):  
B. Aubert ◽  
R. Barate ◽  
D. Boutigny ◽  
F. Couderc ◽  
J.-M. Gaillard ◽  
...  
Keyword(s):  

2002 ◽  
Vol 66 (5) ◽  
Author(s):  
S. B. Athar ◽  
P. Avery ◽  
H. Stoeck ◽  
J. Yelton ◽  
G. Brandenburg ◽  
...  
Keyword(s):  

1992 ◽  
Vol 69 (14) ◽  
pp. 2041-2045 ◽  
Author(s):  
F. Butler ◽  
X. Fu ◽  
G. Kalbfleisch ◽  
M. Lambrecht ◽  
W. R. Ross ◽  
...  
Keyword(s):  

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