scholarly journals A Simultaneous Measurement of the Branching Fractions of Ten B to Double Charm Decays

2008 ◽  
Author(s):  
Chung Khim Lae
Keyword(s):  
Simultaneous Measurement ◽  
Branching Fractions ◽  
Charm Decays ◽  
Double Charm

scholarly journals Double charm decays ofBcmeson in the perturbative QCD approach

2012 ◽  
Vol 86 (7) ◽  
Author(s):  
Rui Zhou ◽  
Zhitian Zou ◽  
Cai-Dian Lü
Keyword(s):  
Perturbative Qcd ◽  
Charm Decays ◽  
Double Charm

scholarly journals A self-consistent framework of topological amplitude and its SU(N) decomposition

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Di Wang ◽  
Cai-Ping Jia ◽  
Fu-Sheng Yu
Keyword(s):  
Symmetry Breaking ◽  
Branching Fractions ◽  
Energy Levels ◽  
Heavy Meson ◽  
Flavor Symmetry ◽  
Quark Loop ◽  
Charm Decays ◽  
Decay Channels ◽  
The Standard Model ◽  
Penguin Operator

Abstract We propose a systematic theoretical framework for the topological amplitudes of the heavy meson decays and their SU(N) decomposition. In the framework, the topologies are expressed in invariant tensors and classified into tree- and penguin-operator-induced diagrams according to which four-quark operators, tree or penguin, being inserted into their effective weak vertexes. The number of possible topologies contributing to one type of decay can be counted by permutations and combinations. The Wigner-Eckhart theorem ensures the topological amplitudes under flavor symmetry are the same for different decay channels. By decomposing the four-quark operators into irreducible representations of SU(N) group, one can get the SU(N) irreducible amplitudes. Taking the D → PP decay (P denoting a pseudoscalar meson) with SU(3)F symmetry as an example, we present our framework in detail. The linear correlation of topologies in the SU(3)F limit is clarified in group theory. It is found there are only nine independent topologies in all tree- and penguin-operator-induced diagrams contributing to the D → PP decays in the Standard Model. If a large quark-loop diagram, named TLP, is assumed, the large ∆ACP and the very different D0→ K+K− and D0→ π+π− branching fractions can be explained with a normal U-spin breaking. Moreover, our framework provides a simple way to analyze the SU(N) breaking effects. The linear SU(3)F breaking and the high order U-spin breaking in charm decays are re-investigated in our framework, which are consistent with literature. Analogous to the degeneracy and splitting of energy levels, we propose the concepts of degeneracy and splitting of topologies to describe the flavor symmetry breaking effects in decay. As applications, we analyze the strange-less D decays in SU(3)F symmetry breaking into Isospin symmetry and the charm-less B decays in SU(4)F symmetry breaking into SU(3)F symmetry.

scholarly journals Exploring charm decays with missing energy in leptoquark models

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Gaber Faisel ◽  
Jhih-Ying Su ◽  
Jusak Tandean
Keyword(s):  
Neutral Current ◽  
Branching Fractions ◽  
Missing Energy ◽  
Sterile Neutrinos ◽  
Charm Decays ◽  
Charmed Baryon ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current ◽  
Meson Mixing ◽  
The Impact

Abstract We investigate the possibility that scalar leptoquarks generate consequential effects on the flavor-changing neutral-current decays of charmed hadrons into final states with missing energy "Image missing" carried away by either standard model or sterile neutrinos. We focus on scenarios involving the R2, $$ {\tilde{R}}_2 $$ R ˜ 2 , and $$ {\overline{S}}_1 $$ S ¯ 1 leptoquarks and take into account various pertinent constraints, learning that meson-mixing ones and those inferred from collider searches can be of significance. We find in particular that the branching fractions of charmed meson decays D →"Image missing", M = π, ρ, and Ds→"Image missing" and singly charmed baryon decays $$ {\Lambda}_c^{+} $$ Λ c + →"Image missing" and Ξc→"Image missing" are presently allowed to attain the 10−7-10−6 levels if induced by R2 and that the impact of $$ {\tilde{R}}_2 $$ R ˜ 2 is comparatively much less. In contrast, the contributions of $$ {\overline{S}}_1 $$ S ¯ 1 , which couples to right-handed up-type quarks and the sterile neutrinos, could lead to branching fractions as high as order 10−3. This suggests that these charmed hadron decays might be within reach of the BESIII and Belle II experiments or future super charm-tau factories and could serve as potentially promising probes of leptoquark interactions with sterile neutrinos.

scholarly journals Double Charm Decays of B Mesons in mSUGRA Model

2011 ◽  
Vol 56 (1) ◽  
pp. 125-133 ◽  
Author(s):  
Lin-Xia Lü ◽  
Zhen-Jun Xiao ◽  
Shuai-Wei Wang ◽  
Wen-Jun Li
Keyword(s):  
B Mesons ◽  
Charm Decays ◽  
Double Charm

scholarly journals Searches for 25 rare and forbidden decays of D+ and $$ {D}_s^{+} $$ mesons

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
◽  
R. Aaij ◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Confidence Level ◽  
Branching Fractions ◽  
Proton Collision ◽  
Proton Proton ◽  
Charm Decays ◽  
Lhcb Experiment ◽  
Decay Modes ◽  
Proton Proton Collision ◽  
Integrated Luminosity

Abstract A search is performed for rare and forbidden charm decays of the form $$ {D}_{(s)}^{+}\to {h}^{\pm }{\mathrm{\ell}}^{+}{\mathrm{\ell}}^{\left(\prime \right)\mp } $$ D s + → h ± ℓ + ℓ ′ ∓ , where h± is a pion or kaon and ℓ(′)± is an electron or muon. The measurements are performed using proton-proton collision data, corresponding to an integrated luminosity of 1.6 fb−1, collected by the LHCb experiment in 2016. No evidence is observed for the 25 decay modes that are investigated and 90 % confidence level limits on the branching fractions are set between 1.4 × 10−8 and 6.4 × 10−6. In most cases, these results represent an improvement on existing limits by one to two orders of magnitude.

Simultaneous Measurement of Bend Direction and Degree of Curvature using Micromachined Grating Fibers

2014 ◽  
Vol 134 (3) ◽  
pp. 41-46
Author(s):  
Hironori Kumazaki ◽  
Munehiro Hiramatsu ◽  
Hisakazu Oguri ◽  
Seiki Inaba ◽  
Kazuhiro Hane
Keyword(s):  
Simultaneous Measurement

Isomerization of the Isoprene Hydroxy Nitrates and Formation of Orthonitrite Compounds

2019 ◽  
Author(s):  
Gabriel da Silva
Keyword(s):  
Hydroxy Group ◽  
Peroxyl Radical ◽  
Branching Fractions ◽  
Membered Ring ◽  
Low Energy ◽  
Peroxyl Radicals ◽  
Aerosol Formation ◽  
Subsequent Removal ◽  
Ring Compounds ◽  
Group Migration

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>

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