Transverse Spin Polarization of $τ^-$ in ${\bar{B}}^0\rightarrow D^{+} τ^- {\barν}$ and Charged Higgs Boson

Hwang, Dae Sung

doi:10.48550/arxiv.1504.06933

Cited by 3 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The above anomalies have been investigated extensively both within model-independent frameworks , as well as in some specific NP models where the b → cτ ντ transition is mediated by leptoquarks [14,15,[36][37][38][39][40][41][42][43][44], charged Higgses [14,[45][46][47][48][49][50][51][52][53][54][55], charged vector bosons [14,[56][57][58], and sparticles [59][60][61]. It is also interesting to point out that, besides the branching ratios, the measured differential distributions dΓ( B → D ( * ) τ ν)/dq 2 by BaBar [7] and Belle [8,9] provide very complementary information to distinguish NP from the SM as well as different NP models from each other [14,39,45].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the one leptoquark solution to the R(D (∗)) anomalies and its phenomenological implications

Yang

Zhang

2016

J. High Energ. Phys.

175

107

View full text Add to dashboard Cite

It has been shown recently that the anomalies observed inB → D ( * ) τν τ andB →K + − decays could be resolved with just one scalar leptoquark. Fitting to the current data on R(D ( * ) ) along with acceptable q 2 distributions inB → D ( * ) τν τ decays, four best-fit solutions for the operator coefficients have been found. In this paper, we explore the possibilities of how to discriminate these four solutions. Firstly, we find that two of them * With the discovery of heavy quark spin-flavor symmetry and the formulation of heavy quark effective theory (HQET) [1][2][3][4][5], it has become clear that the physical observables in semi-leptonic B → D ( * ) ν could be rather reliably predicted within the Standard Model (SM), especially at the zero recoil point, allowing therefore a reliable determination of the Cabibbo-Kobayashi-Maskawa (CKM) element V cb . It is also believed that the effect of New Physics (NP) beyond the SM should be tiny since these decays are induced by the tree-level charged current.However, the BaBar [6, 7], Belle [8,9] and LHCb [10] collaborations have recently observed anomalies in the ratios R(D ( * ) ) = B(B → D ( * ) τν τ ) B(B → D ( * ) ν ) , = e/µ . (1.1) The Heavy Flavor Average Group (HFAG) gives the average values [11] R(D) avg =0.397 ± 0.040 ± 0.028 , R(D * ) avg =0.316 ± 0.016 ± 0.010 , (1.2) which exceed the SM predictions [12, 13] R(D) SM =0.300 ± 0.008 , R(D * ) SM =0.252 ± 0.003 , (1.3) by 1.9σ and 3.3σ, respectively. Especially when the R(D)-R(D * ) correlation of −0.21 is taken into account, the tension with the SM predictions would be at 4.0σ level [11]. Theoretically, R(D) and R(D * ) can be rather reliably calculated, because they are independent of the CKM element |V cb | and, to a large extent, of the B → D ( * ) transition form factors.The above anomalies have been investigated extensively both within model-independent frameworks [14-35], as well as in some specific NP models where the b → cτν τ transition is mediated by leptoquarks [14, 15, 36-44], charged Higgses [14, 45-55], charged vector bosons [14, 56-58], and sparticles [ [59][60][61]. It is also interesting to point out that, besides the branching ratios, the measured differential distributions dΓ(B → D ( * ) τν)/dq 2 by BaBar [7] and Belle [8,9]

show abstract

Section: Introductionmentioning

confidence: 99%

Revisiting the one leptoquark solution to the R(D (∗)) anomalies and its phenomenological implications

Yang

Zhang

2016

J. High Energ. Phys.

175

107

View full text Add to dashboard Cite

show abstract

“…As shown in Figure 1, one could also define polarizations projecting the τ spin on the p X direction, or the direction transverse to the plane spanned by p B , p X , and p ν . A nonzero τ polarization in this transverse direction, x, violates CP [3][4][5][6][7][8]. It therefore vanishes in the SM, but could be generated by new physics.…”

Section: Introductionmentioning

confidence: 99%

Exploring the $τ$ polarization in $B\to Xτ\barν$ along different axes

Bernlochner¹,

Ligeti²,

Papucci³

et al. 2023

Preprint

View full text Add to dashboard Cite

The τ polarization in semileptonic B decays provides probes of new physics complementary to decay rate distributions of the three-body final state. Prior calculations for inclusive decays used a definition for the polarization axis that is different from the choice used in calculations (and the only measurement) for exclusive channels. To compare inclusive and exclusive predictions, we calculate the τ polarization in inclusive B → Xτ ν using the same choice as in the exclusive decays, and construct a sum rule relating the inclusive τ polarization to a weighted sum of exclusive decay polarizations. We use this relation, experimental data, and theoretical predictions for the decays to the lightest charm or up-type hadrons to make predictions for excited channels.

show abstract

“…The large deviations in R D ( * ) and possible anomalies in the other decay channels mentioned above imply possible hints of NP relevant to the lepton flavor violation (LFV) [15]. The investigations for these anomalies have been made extensively both within model-independent frameworks , as well as in some specific NP models where the b → cτ ντ transition is mediated by leptoquarks [16,17,[38][39][40][41][42][43][44][45][46], charged Higgses [16,[47][48][49][50][51][52][53][54][55][56][57][58][59], charged vector bosons [16,60,61], and sparticles [62][63][64][65].…”

Section: Introductionmentioning

confidence: 99%

Probing the effects of new physics in $\bar{B}^* \to P \ell \barν_\ell$ decays

Chang,

Zhu,

Wang

et al. 2018

Preprint

View full text Add to dashboard Cite

The significant divergence between the SM predictions and experimental measurements for the ratios, R D ( * ) ≡ B( B → D ( * ) τ − ντ )/B( B → D ( * ) − ν ) with ( = e , µ), implies possible hint of new physics in the flavour sector. In this paper, motivated by the "R D ( * ) puzzle" and abundant B * data samples at high-luminosity heavy-flavor experiments in the future, we try to probe possible effects of new physics in the semileptonic B * u,d,s → P − ν (P = D , D s , π , K) decays induced by b → (u, c) − ν transitions in the model-independent vector and scalar scenarios. Using the spaces of NP parameters ob-tained by fitting to the data of R D and R D * , the NP effects on the observables including branching fraction, ratio R * P , lepton spin asymmetry and lepton forward-backward asymmetry are studied in detail. We find that the vector type couplings have large effects on the branching fraction and ratio R * P . Meanwhile, the scalar type couplings provide significant contributions to all of the observables. The future measurements of these observables in the B * → P − ν decays at the LHCb and Belle-II could provide a way to crosscheck the various NP solutions to the "R D ( * ) puzzle".

show abstract

Transverse Spin Polarization of $τ^-$ in ${\bar{B}}^0\rightarrow D^{+} τ^- {\barν}$ and Charged Higgs Boson

Cited by 3 publications

References 17 publications

Revisiting the one leptoquark solution to the R(D (∗)) anomalies and its phenomenological implications

Revisiting the one leptoquark solution to the R(D (∗)) anomalies and its phenomenological implications

Exploring the $τ$ polarization in $B\to Xτ\barν$ along different axes

Probing the effects of new physics in $\bar{B}^* \to P \ell \barν_\ell$ decays

Contact Info

Product

Resources

About