Nuclear Theory·nucl-th

Friday·August 26, 2022

9 papers—6 primary·3 cross-listed

07
Scrutinizing CKM unitarity with a new measurement of the $K_{μ 3} / K_{μ 2}$ branching fraction
Vincenzo Cirigliano🇺🇸 · Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭 · Matthew Moulson🇨🇭
Precision tests of first-row unitarity of the Cabibbo-Kobayashi-Maskawa matrix currently display two intriguing tensions, both at the $3 σ$ level. First, combining determinations of $V_{u d}$ from superallowed $β$ decays with $V_{u s}$ from kaon decays suggests a deficit in the unitarity relation. At the same time, a tension of similar significance has emerged between $K_{ℓ 2}$ and $K_{ℓ 3}$ decays. In this Letter, we point out that a measurement of the $K_{μ 3} / K_{μ 2}$ branching fraction at the level of $0.2%$ would have considerable impact on clarifying the experimental situation in the kaon sector, especially in view of tensions in the global fit to kaon data as well as the fact that the $K_{μ 2}$ channel is currently dominated by a single experiment. Such a measurement, as possible for example at NA62, would further provide important constraints on physics beyond the Standard Model, most notably on the role of right-handed vector currents.
↳ hep-phhep-exhep-latnucl-thPLB(2023)·115 citations
08
How many quantum gates do gauge theories require?
Edison M. Murairi🇺🇸 · Michael J. Cervia🇺🇸 · Hersh Kumar🇺🇸 · Paulo F. Bedaque🇺🇸 · Andrei Alexandru🇺🇸
We discuss the implementation of lattice gauge theories on digital quantum computers, focusing primarily on the number of quantum gates required to simulate their time evolution. We find that to compile quantum circuits, using available state-of-the-art methods with our own augmentations, the cost of a single time step of an elementary plaquette is beyond what is reasonably practical in the current era of quantum hardware. However, we observe that such costs are highly sensitive to the truncation scheme used to derive different Hamiltonian formulations of non-Abelian gauge theories, emphasizing the need for low-dimensional truncations of such models in the same universality class as the desired theories.
↳ hep-latnucl-thquant-phPRD(2022)·45 citations
09
Pole determination of $P_{ψ s}^{Λ} (4338)$ and possible $P_{ψ s}^{Λ} (4255)$ in $B^{-} \to J / ψ Λ p ˉ$
S.X. Nakamura (Univ. of Science and Technology of China)🇨🇳 · J.-J. Wu (Univ. of Chinese Academy of Sciences)🇨🇳
First hidden-charm pentaquark candidate with strangeness, $P_{ψ s}^{Λ} (4338)$ , was recently discovered in $B^{-} \to J / ψ Λ p ˉ$ by the LHCb Collaboration. $P_{ψ s}^{Λ} (4338)$ shows up as a bump at the $Ξ_{c} D ˉ$ threshold in the $J / ψ Λ$ invariant mass ( $M_{J / ψ Λ}$ ) distribution. The $M_{J / ψ Λ}$ distribution also shows a large fluctuation at the $Λ_{c} D ˉ_{s}$ threshold, hinting the existence of a possible $P_{ψ s}^{Λ} (4255)$ . In this work, we determine the $P_{ψ s}^{Λ} (4338)$ and $P_{ψ s}^{Λ} (4255)$ pole positions for the first time. For this purpose, we fit a $B^{-} \to J / ψ Λ p ˉ$ model to the $M_{J / ψ Λ}$ , $M_{J / ψ p ˉ}$ , $M_{Λ p ˉ}$ , and $cos θ_{K^{*}}$ distributions from the LHCb simultaneously; $χ^{2} / ndf \sim 1.21$ . Then we extract $P_{ψ s}^{Λ}$ poles from a unitary $Ξ_{c} D ˉ$ - $Λ_{c} D ˉ_{s}$ coupled-channel scattering amplitude built in the model. In our default fit, the $P_{ψ s}^{Λ} (4338)$ pole is found at $(4338.2 \pm 1.4) - (1.9 \pm 0.5) i$ MeV while the $P_{ψ s}^{Λ} (4255)$ pole at $4254.7 \pm 0.4$ MeV. The $P_{ψ s}^{Λ} (4338)$ and $P_{ψ s}^{Λ} (4255)$ are mostly $Ξ_{c} D ˉ$ bound and $Λ_{c} D ˉ_{s}$ virtual states, respectively. Through our analysis, the data disfavors a hypothesis of $P_{ψ s}^{Λ} (4338)$ as merely a kinematical effect. This pole determination, which is important in its own right, sets a primary basis to study the nature of the $P_{ψ s}^{Λ}$ states.
↳ hep-phhep-exnucl-thPRD(2023)·48 citations

Affiliations

first authorsco-authorsvia INSPIRE

Scrutinizing CKM unitarity with a new measurement of the Kμ3​/Kμ2​ branching fraction

How many quantum gates do gauge theories require?

Pole determination of PψsΛ​(4338) and possible PψsΛ​(4255) in B−→J/ψΛpˉ​

Affiliations

Scrutinizing CKM unitarity with a new measurement of the $K_{μ 3} / K_{μ 2}$ branching fraction

Pole determination of $P_{ψ s}^{Λ} (4338)$ and possible $P_{ψ s}^{Λ} (4255)$ in $B^{-} \to J / ψ Λ p ˉ$