Test of lepton flavor universality using B0→D*−τ+ν

Lepton universality tests and searches for new physics in charged current decays at Belle II

“…A weighted average of correlated values yields 𝑅(𝑋 𝜏/ℓ ) = 0.228 ± 0.016 ± 0.036. (10) Our result aligns with its SM prediction of 𝑅(𝑋 𝜏/ℓ ) SM = 0.223 ± 0.005, as derived in an arithmetic average of Refs. [30,38,39], and also is consistent with the current experimental world average of 𝑅(𝐷 ( * ) 𝜏/ℓ ).…”

“…Figure 3: Our presented 𝑅(𝐷 *𝜏/ℓ ) and 𝑅(𝑋 𝜏/ℓ )[36] results (red) compared to related individual measurements (gold)[3][4][5][6][7][8][9][10] and the current world average (blue) as reported in Ref [11]…”

“…Additionally, the fundamental principle of LU is challenged in a combination of several measurements of the ratios 𝑅(𝐷 ( * ) 𝜏/ℓ ) = B (𝐵 → 𝐷 ( * ) 𝜏 − 𝜈 𝜏 )/B (𝐵 → 𝐷 ( * ) ℓ − 𝜈 ℓ ) [3][4][5][6][7][8][9][10], resulting in a tension between experimental results and SM expectations of 3.3 𝜎 [11]. In Sections 6 and 7, we present two results that test this tension.…”

Analysis of anomalies using weak effective Hamiltonian with complex couplings and their impact on various physical observables

“…In the SM, the heavy-quark effective theory and lattice QCD approach have been used to study the LFU ratio [14][15][16][17][18][19][20][21][22][23][24]. The corresponding SM results are These theoretical results were scrutinized using measurements from BABAR, Belle, and LHCb, where the experimental measurements of by BABAR [25,26], Belle [27][28][29], and LHCb [30][31][32][33][34] had significant deviations from the SM predictions. Recently, the Heavy Flavor Averaging Group (HFLAV) updated their earlier results of and [35,36], and the current world averages [37] exceed the SM predictions by and , respectively.…”