{
  "abstract": "The decays $\\bar{B}\\rightarrow D^*τ^{-}\\barν_τ$ provide sensitive probes of new physics in the $b\\rightarrow cτν$ transition. We discuss the effects of new physics in the decay chain $\\bar{B}\\rightarrow D^*(\\rightarrow Dπ)τ^{-}(\\rightarrow V^-ν_τ)\\barν_τ$ where $V$ is a vector meson. We first present a comprehensive analysis of the five-dimensional angular distribution for the full decay chain $\\bar{B}\\rightarrow D^*(\\rightarrow Dπ)τ^{-}(\\rightarrow ρ^-ν_τ)\\barν_τ$, exploiting the hadronic $τ$ decay to $ρ^-ν_τ$ to circumvent the experimental challenge of direct $τ$ reconstruction. The differential decay rate is expressed in terms of measurable kinematic variables $θ^*$, $E_ρ$, $θ_ρ$, $χ_ρ$, and $q^2$ -- with complete coefficient functions provided for scalar, pseudoscalar, vector, axialvector, and tensor new-physics interactions. From this distribution we construct a set of integrated observables, including the $D^*$ polarization fractions and lepton-side forward-backward and azimuthal asymmetries, which isolate distinct combinations of helicity amplitudes. We also show that by decomposing the vector-meson energy spectrum into its longitudinal ($L$) and transverse ($T$) helicity sectors, two additional analyzing powers ($α_L$ and $α_T$) related to the measurement of $τ$ polarization $P_τ^{D^*}(q^2)$ are obtained. Without information on the polarization of meson $V$, the spin analyzing power of $ρ$ is much larger than that of $a_1$ with $α_ρ=0.45$ and $α_{a_1}=0.02$. We further perform a numerical analysis using current experimental data on $R_{D^*}$ and the $D^*$ longitudinal polarization fraction $\\langle F_L^{D^*}\\rangle$ to constrain the complex new-physics couplings $g_L$, $g_R$, $g_P$, and $g_T$, revealing the correlations among them.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.15166",
  "author_total": 3,
  "authors": [
    {
      "name": "Si-Yuan Liu"
    },
    {
      "name": "Alakabha Datta"
    },
    {
      "name": "Xian-Wei Kang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dkfn8hbfcpnt0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.15166",
  "fulltext_url": null,
  "id": "dkfn8hbfcpnt0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.15166",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Particle physics theoretical and experimental studies"
    ]
  ],
  "openalex": "W7164956874",
  "pdf_url": "https://arxiv.org/pdf/2606.15166",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dkfn8hbfcpnt0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:48Z",
      "native_id": "2606.15166",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.15166"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Exploring new physics in the angular distribution of $\\bar B\\rightarrow D^*(\\rightarrow Dπ)τ^-(\\rightarrow V^-ν_τ)\\barν_τ$",
  "title_text": "Exploring new physics in the angular distribution of B̅→ D^*(→ Dπ)τ^-(→ V^-ν_τ)ν̅_τ",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:48Z",
  "url": "https://research.draconitic.com/paper/dkfn8hbfcpnt0",
  "venue": "arXiv",
  "versions": []
}