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Albertus, C.; Hernández, E.; Nieves, J.

doi:10.1103/physrevd.90.013017

“…There we also compare with the masses obtained previously using the AL1 potential. We see a small increase in the masses of roughly 26,34,40 respectively. Effects here are similar to those due to the hyperfine splitting.…”

Section: Nonrelativistic Quark Model Evaluation Of the Isgur-wise Fun...mentioning

confidence: 81%

Triply heavy baryons and heavy quark spin symmetry

Flynn

¹

,

Hernández

²

,

Nieves

³

2012

Self Cite

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We study the semileptonic b → c decays of the lowest-lying triply-heavy baryons made from b and c quarks in the limit m b , mc ≫ ΛQCD and close to the zero recoil point. The separate heavy quark spin symmetries strongly constrain the matrix elements, leading to single form factors for ccb → ccc, bbc → ccb, and bbb → bbc baryon decays. We also study the effects on these systems of using a Y -shaped confinement potential, as suggested by lattice QCD results for the interaction between three static quarks.

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“…We perform a fit of three B → ρ form factors V, A 1 and A 2 following a similar procedure as in Refs. [63,64]. The form factor A 12 , which is used in our parametrization in Eq.…”

Section: B → ρmentioning

confidence: 99%

Interplay of dineutrino modes with semileptonic rare $\boldsymbol{B}$-decays

Bause,

Gisbert,

Golz

et al. 2021

Preprint

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We present a systematic global analysis of dineutrino modes b → q ν ν, q = d, s, and charged dilepton b → q + − transitions. We derive improved or even entirely new limits on dineutrino branching ratios including decays B 0 → (K 0 , Xs) ν ν, Bs → φ ν ν and B 0 → (π 0 , ρ 0 ) ν ν from dineutrino modes which presently are best constrained: B + → (K + , π + , ρ + ) ν ν and B 0 → K * 0 ν ν. Using SMEFT we obtain new flavor constraints from the dineutrino modes, which are stronger than the corresponding ones from charged dilepton rare b-decay or Drell-Yan data, for eτ and τ τ final states, as well as for µτ ones in b → s processes. The method also allows to put novel constraints on semileptonic four-fermion operators with top quarks. Implications for ditau modes b → s τ + τ − and b → d τ + τ − are worked out. Even stronger constraints are obtained in simplified BSM frameworks such as leptoquarks and Z -models. Furthermore, the interplay between dineutrinos and charged dileptons allows for concrete, novel tests of lepton universality in rare B-decays. Performing a global fit to b → s µ + µ − , sγ transitions we find that lepton universality predicts the ratio of the B 0 → K * 0 ν ν to B 0 → K 0 ν ν (B + → K + ν ν) branching fractions to be within 1.7 to 2.6 (1.6 to 2.4) at 1 σ, a region that includes the standard model, and that can be narrowed with improved charged dilepton data. There is sizable room outside this region where universality is broken and that can be probed with the Belle II experiment. Using results of a fit to B 0 → µ + µ − , B 0 s → K * 0 µ + µ − and B + → π + µ + µ − data we obtain an analogous relation for |∆b| = |∆d| = 1 transitions: if lepton universality holds the ratio of the B 0 → ρ 0 ν ν to B 0 → π 0 ν ν (B + → π + ν ν) branching fractions is within 2.5 to 5.7 (1.2 to 2.6) at 1 σ. Putting upper limits on B(Bs → ν ν) at the level of 10 −5 and B(B 0 → ν ν) below 10 −6 would allow to control backgrounds from (pseudo-)scalar operators such as those induced by light right-handed neutrinos.

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“…We perform a fit of three B → ρ form factors V, A 1 and A 2 following a similar procedure as in refs. [67,68]. The form factor A 12 , which is used in our parametrization in eq.…”

Section: C2 B → ρmentioning

confidence: 99%

Interplay of dineutrino modes with semileptonic rare B-decays

Bause

¹

,

Gisbert

²

,

Golz

³

et al. 2021

J. High Energ. Phys.

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We present a systematic global analysis of dineutrino modes b → qν$$ \overline{\nu} $$ ν ¯ , q = d, s, and charged dilepton b → qℓ+ℓ− transitions. We derive improved or even entirely new limits on dineutrino branching ratios including decays B0→ (K0, Xs)ν$$ \overline{\nu} $$ ν ¯ , Bs→ ϕν$$ \overline{\nu} $$ ν ¯ and B0→ (π0, ρ0)ν$$ \overline{\nu} $$ ν ¯ from dineutrino modes which presently are best constrained: B+→ (K+, π+, ρ+)ν$$ \overline{\nu} $$ ν ¯ and B0→ K*0ν$$ \overline{\nu} $$ ν ¯ . Using SMEFT we obtain new flavor constraints from the dineutrino modes, which are stronger than the corresponding ones from charged dilepton rare b-decay or Drell-Yan data, for eτ and ττ final states, as well as for μτ ones in b → s processes. The method also allows to put novel constraints on semileptonic four-fermion operators with top quarks. Implications for ditau modes b → sτ+τ− and b → dτ+τ− are worked out. Even stronger constraints are obtained in simplified BSM frameworks such as leptoquarks and Z′-models. Furthermore, the interplay between dineutrinos and charged dileptons allows for concrete, novel tests of lepton universality in rare B-decays. Performing a global fit to b → sμ+μ−, sγ transitions we find that lepton universality predicts the ratio of the B0→ K*0ν$$ \overline{\nu} $$ ν ¯ to B0→ K0ν$$ \overline{\nu} $$ ν ¯ (B+→ K+ν$$ \overline{\nu} $$ ν ¯ ) branching fractions to be within 1.7 to 2.6 (1.6 to 2.4) at 1σ, a region that includes the standard model, and that can be narrowed with improved charged dilepton data. There is sizable room outside this region where universality is broken and that can be probed with the Belle II experiment. Using results of a fit to B0→ μ+μ−, $$ {B}_s^0 $$ B s 0 →$$ \overline{K} $$ K ¯ *0μ+μ− and B+→ π+μ+μ− data we obtain an analogous relation for |∆b| = |∆d| = 1 transitions: if lepton universality holds the ratio of the B0→ ρ0ν$$ \overline{\nu} $$ ν ¯ to B0→ π0ν$$ \overline{\nu} $$ ν ¯ (B+→ π+ν$$ \overline{\nu} $$ ν ¯ ) branching fractions is within 2.5 to 5.7 (1.2 to 2.6) at 1 σ. Putting upper limits on $$ \mathcal{B} $$ B (Bs→ ν$$ \overline{\nu} $$ ν ¯ ) at the level of 10−5 and $$ \mathcal{B} $$ B (B0→ ν$$ \overline{\nu} $$ ν ¯ ) below 10−6 would allow to control backgrounds from (pseudo-)scalar operators such as those induced by light right-handed neutrinos.

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B→ρsemileptonic decays and|Vub|

Cited by 8 publications

References 22 publications

Triply heavy baryons and heavy quark spin symmetry

Triply heavy baryons and heavy quark spin symmetry

Interplay of dineutrino modes with semileptonic rare $\boldsymbol{B}$-decays

Interplay of dineutrino modes with semileptonic rare B-decays

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