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Related papers: Resolving $R_D$ and $R_{D^*}$ anomalies

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One of the exciting results in flavor physics in recent times is the $R_D$/$R_{D^*}$ puzzle. The measurements of these flavor ratios performed by the B-factory experiments, BaBar and Belle, and the LHCb experiment are about $4\sigma$ away…

High Energy Physics - Phenomenology · Physics 2018-07-31 Ashutosh Kumar Alok , Dinesh Kumar , Suman Kumbhakar , S Uma Sankar

Deviations from the standard model predictions have been reported in various observables concerned with the lepton flavor universality. At present, the deviation of the measured values of $R_D$ and $R_{D^{\ast}}$ from the standard model…

High Energy Physics - Phenomenology · Physics 2017-10-19 Rupak Dutta

At Moriond 2019, Belle collaboration has announced new measurements on the flavour ratios $R_D - R_{D^*}$ which are consistent with their Standard Model predictions within $1.2\sigma$. After inclusion of these measurements, the global…

High Energy Physics - Phenomenology · Physics 2021-01-07 Suman Kumbhakar , Ashutosh Kumar Alok , Dinesh Kumar , S. Uma Sankar

At Moriond 2019, Belle collaboration announced their new measurements on $R_D$ and $R_{D^*}$ which are in agreement with their Standard Model (SM) predictions within $1.2\sigma$. After inclusion of these measurements, the discrepancy…

High Energy Physics - Phenomenology · Physics 2021-01-07 Suman Kumbhakar , Ashutosh Kumar Alok , Dinesh Kumar , S. Uma Sankar

Deviation from the standard model prediction is observed in many semileptonic $B$ decays mediated via $b \to c$ charged current interactions. In particular, current experimental measurements of the ratio of branching ratio $R_D$ and…

High Energy Physics - Phenomenology · Physics 2019-08-20 Rupak Dutta , N Rajeev

Deviation from the standard model prediction is observed in many semileptonic $B$ decays mediated via $b \to c$ charged current interactions. In particular, current experimental measurements of the ratio of branching ratio $R_D$ and…

High Energy Physics - Phenomenology · Physics 2018-06-06 Rupak Dutta , Rajeev N

The measurement of $R_D$ ($R_{D^*}$), the ratio of the branching fraction of $\overline{B} \to D \tau \bar{\nu}_\tau (\overline{B} \to D^* \tau \bar{\nu}_\tau)$ to that of $\overline{B} \to D l \bar{\nu}_l (\overline{B} \to D^* l…

High Energy Physics - Phenomenology · Physics 2018-06-26 Debjyoti Bardhan , Pritibhajan Byakti , Diptimoy Ghosh

The experimental predictions of $R_D$, $R_{D^*}$, $R_{J/\psi}$, $P_\tau^{D^*}$ and $F_L^{D^*}$ in $B$ decays mediated via $b\,\to\, c\, l\,\nu$ quark level transition deviate significantly from the standard model expectations. The current…

High Energy Physics - Phenomenology · Physics 2020-10-28 Nilakshi Das , Rupak Dutta

The flavor changing decays of heavy bottom quarks to the corresponding lighter quarks ($u$, $c$ and $s$) in various $B$-meson decays via charged current and neutral current semileptonic transitions have emerged as promising candidates to…

High Energy Physics - Phenomenology · Physics 2019-08-28 N Rajeev , Rupak Dutta , Suman Kumbhakar

The measurement of $R_D$ ($R_{D^*}$), the ratio of the branching fraction of $\overline{B} \to D \tau \bar{\nu}_\tau (\overline{B} \to D^* \tau \bar{\nu}_\tau)$ to that of $\overline{B} \to D l \bar{\nu}_l (\overline{B} \to D^* l…

High Energy Physics - Phenomenology · Physics 2017-05-25 Debjyoti Bardhan

Recently, the LHCb collaboration announced a preliminary result of the test of lepton flavor universality (LFU) in $B\to D^{(\ast)}$ semi-leptonic decays: $R_{D}^{\rm LHCb2022} = 0.441 \pm 0.089$ and $R_{D^{\ast}}^{\rm LHCb2022} = 0.281 \pm…

High Energy Physics - Phenomenology · Physics 2024-05-30 Syuhei Iguro , Teppei Kitahara , Ryoutaro Watanabe

Recently, several new experimental results of the test of lepton flavor universality (LFU) in $B\to D^{(\ast)}$ semi-leptonic decays were announced: the first result of $R_{D}$ from the LHCb Run 1 data, the first results of $R_{D}$ and…

High Energy Physics - Phenomenology · Physics 2024-10-11 Syuhei Iguro , Teppei Kitahara , Ryoutaro Watanabe

The BaBar Collaboration has recently reported the measurement of the ratio of the branching fractions of $\bar{B} \to D(D^{*}) \tau^{-} \bar{\nu_\tau}$ to $\bar{B} \to D(D^{*}) \ell^{-} \bar{\nu_\ell}$ which deviates from the Standard Model…

High Energy Physics - Phenomenology · Physics 2018-03-13 Alakabha Datta , Murugeswaran Duraisamy , Diptimoy Ghosh

Hints of lepton flavor universality violation observed in various flavor ratios such as $R_D$, $R_{D^*}$, $R_{J/\psi}$, $P_\tau^{D^*}$ and $F_L^{D^*}$ in $B\to D^{(*)}\,\ell \, \nu$ and $B_c\to J/\psi \, \ell\, \nu$ charge current decays…

High Energy Physics - Phenomenology · Physics 2022-04-13 Nilakshi Das , Rupak Dutta

This paper reviews the recent progresses of the flavor and collider searches that can probe New Physics effects responsible for the current discrepancy in the lepton flavor universality ratio of $R_{D^{(*)}}$ between the experimental…

High Energy Physics - Phenomenology · Physics 2022-07-28 Ryoutaro Watanabe

The observable $\mathcal{R} \left( D^{(*)} \right) = \mathcal{B}\left( B^{0}\to D^{(*)-} \tau^{+} \nu_{\tau} \right) / \mathcal{B}\left( B^{0}\to D^{(*)-} \mu^{+} \nu_{\mu} \right)$ is a probe for Lepton Universality violation, so it is…

High Energy Physics - Experiment · Physics 2019-08-14 Federico Betti

The deviation of the measurement of $R_{D}$ ($R_{D^{*}}$) from the Standard Model (SM) expectation is $2.3\sigma$ ($3.1\sigma$). $R_{D}$ ($R_{D^{*}}$) is the ratio of the branching fraction of $\overline{B} \rightarrow…

High Energy Physics - Phenomenology · Physics 2024-11-28 Zhong-Jun Yang , Shu-Min Zhao , Xing-Xing Dong , Xi-Jie Zhan , Hai-Bin Zhang , Tai-Fu Feng

In the past few years, several hints of lepton flavour universality (LFU) violation have emerged in the $b \to c \tau \bar\nu$ and $b \to s \ell^+ \ell^-$ data. Quite recently, the Belle Collaboration has reported the first measurement of…

High Energy Physics - Phenomenology · Physics 2019-07-23 Dong-Yang Wang , Ya-Dong Yang , Xing-Bo Yuan

The confirmation of excess in $R_{D^*}$ at the LHCb is an indication of lepton flavor non-universality. Various different new physics operators and their coupling strengths, which provide a good fit to $R_D$, $R_{D^*}$ and $q^2$ spectra,…

High Energy Physics - Phenomenology · Physics 2017-07-31 Ashutosh Kumar Alok , Dinesh Kumar , Suman Kumbhakar , S Uma Sankar

Recently hints of lepton flavor non-universality emerged when the BaBar Collaboration observed deviations from the standard model predictions in $R(D^{(*)}) \equiv {\cal B}({\bar B} \to D^{(*)+} \tau^- {\bar\nu}_\tau) / {\cal B}({\bar B}…

High Energy Physics - Phenomenology · Physics 2015-06-10 Shanmuka Shivashankara , Wanwei Wu , Alakabha Datta
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