Search for new physics in B -> VV decays and other hot topics from Belle

TL;DR

This study measures polarization fractions in specific B meson decays to vector mesons, revealing discrepancies from Standard Model predictions that could indicate new physics beyond current theories.

Contribution

First measurement of polarization fractions in B -> VV decays at Belle, suggesting potential new physics contributions beyond the Standard Model.

Findings

Measured polarization fractions f_L in three decay modes.

Discrepancy between measured f_L and theoretical expectation of ~1.

Results imply possible new amplitude contributions.

Abstract

We report studies in polarization in B decay into two vector mesons with data equivalent to $253 {\rm fb^{-1}}$ on $\Upsilon(4S)$ resonance at KEKB. In $B^0 \to \phi K^{*0}$, $B^+ \to \phi K^{*+}$ and $B^+ \to \rho^+ K^{*0}$ decays, we determine $f_L = 0.45 \pm 0.05({\rm stat.}) \pm 0.02({\rm syst.})$, $f_L = 0.52 \pm 0.08({\rm stat.}) \pm 0.03({\rm syst.})$ and $f_L = 0.43 \pm 0.11({\rm stat.}) ^{+ 0.05}_{-0.02}({\rm syst.})$ respectively, where $f_L$ is a ratio between longitudinal and transverse polarization, and a na\"{i}ve theoretical estimation assumes $f_L \sim 1$. The discrepancy from 1 in $f_L$ may suggest existence of new amplitude within or/and beyond the Standard Model.