Nuclear Theory·nucl-th

Tuesday·May 19, 2020

14 papers—8 primary·6 cross-listed

09
Role of chiral two-body currents in $^{6}$ Li magnetic properties in light of a new precision measurement with the relative self-absorption technique
U. Friman-Gayer · C. Romig · T. Hüther · K. Albe · S. Bacca · T. Beck · M. Berger · J. Birkhan · K. Hebeler · O. J. Hernandez · J. Isaak · S. König and 9 other authors
A direct measurement of the decay width of the excited $0_{1}^{+}$ state of $^{6}$ Li using the relative self-absorption technique is reported. Our value of $Γ_{γ, 0_{1}^{+} \to 1_{1}^{+}} = 8.17 (14)_{stat.} (11)_{syst.} eV$ provides sufficiently low experimental uncertainties to test modern theories of nuclear forces. The corresponding transition rate is compared to the results of ab initio calculations based on chiral effective field theory that take into account contributions to the magnetic dipole operator beyond leading order. This enables a precision test of the impact of two-body currents that enter at next-to-leading order.
↳ nucl-exnucl-thPRL(2021)·25 citations
10
Precision measurement of $^{210}$ Bi $β$ -spectrum
I.E. Alekseev🇷🇺 · S.V. Bakhlanov🇷🇺 · A.V. Derbin🇷🇺 · I.S. Drachnev🇷🇺 · I.M. Kotina🇷🇺 · I.S. Lomskaya🇷🇺 · V.N. Muratova🇷🇺 · N.V. Niyazova🇷🇺 · D.A. Semenov🇷🇺 · M.V. Trushin🇷🇺 · E.V. Unzhakov🇷🇺
The precision measurement of the $β -$ spectrum shape for $^{210}$ Bi (historically RaE) have been performed with a spectrometer based on semiconductor Si(Li) detector. This first forbidden non-unique transition has the transition form-factor strongly deviated from unity and knowledge of its spectrum would play an important role in low-background physics in presence of $^{210}$ Pb background. The measured transition form-factor could be approximated as $S (W) = 1 + (- 0.4363 \pm 0.0037) W + (0.0523 \pm 0.0010) W^{2}$ , that is in good agreement with previous studies and has significantly increased parameter precision.
↳ nucl-exhep-exhep-phnucl-th+1PRC(2021)·12 citations
11
Two-photon decays and transition form factors of $π^{0}$ , $η$ , and $η^{'}$ in large- $N_{c}$ chiral perturbation theory
Patricia Bickert🇩🇪 · Stefan Scherer🇩🇪
We present a calculation of $P \to γ^{(*)} γ^{(*)}$ processes, where $P = π^{0}, η, η^{'}$ , at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large- $N_{c}$ chiral perturbation theory. The results are numerically evaluated successively at LO, NLO, and NNLO. The appearing low-energy constants are determined through fits to the available experimental data. We investigate the decay widths to real photons, the single-virtual transition form factors, and the widths of $P \to γ l^{+} l^{-}$ , where $l = e, μ$ . Furthermore, we provide results for the slopes and curvatures of the transition form factors.
↳ hep-phnucl-exnucl-thPRD(2020)·16 citations
12
Statistical Behavior of Lepton Pair Spectrum in Drell-Yan Process and Signal from Quark-Gluon Plasma in High Energy Collisions
Xu-Hong Zhang🇨🇳 · Fu-Hu Liu🇨🇳
We analyze the transverse momentum ( $p_{T}$ ) spectra of lepton pairs ( $ℓ ℓ ˉ$ ) generated in the Drell-Yan process, as detected in proton-nucleus (pion-nucleus) and proton-(anti)proton collisions by ten collaborations over a center-of-mass energy ( $s_{N N}$ or $s$ if in a simplified form) range from $\sim 20$ GeV to above 10 TeV. Three types of probability density functions (the convolution of two Lévy-Tsallis functions, the two-component Erlang distribution, and the convolution of two Hagedorn functions) are utilized to fit and analyze the $p_{T}$ spectra. The fit results are approximately in agreement with the collected experimental data. Consecutively, we obtained the variation law of related parameters as a function of $s$ and invariant mass ( $Q$ ). In the fit procedure, a given Lévy-Tsallis (or Hagedorn) function can be regarded as the probability density function of transverse momenta contributed by a single quark ( $q$ ) or anti-quark ( $q ˉ$ ). The Drell-Yan process is then described by the statistical method.
↳ hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2021)·1 citation
13
Solutions to Problems at Les Houches Summer School on EFT
Marcel Balsiger🇨🇭 · Marios Bounakis🇬🇧 · Mehdi Drissi🇫🇷 · John Gargalionis🇦🇺 · Erik Gustafson🇺🇸 · Greg Jackson🇨🇭 · Matthew Leak🇬🇧 · Christopher Lepenik🇦🇹 · Scott Melville🇬🇧 · Daniel Moreno🇪🇸 · Michele Tammaro🇺🇸 · Selim Touati🇫🇷 · Timothy Trott🇺🇸
This work details worked solutions to the various problems set by the lecturers during the course of the Les Houches summer school 2017 on effective field theories in particle physics and cosmology.
↳ hep-phgr-qcnucl-thLes Houches Lect.Notes(2020)·3 citations
14
Hadronization of heavy diquark and light quark within NJL-Model
Yu-Ji Shi🇩🇪
We present a path-integral hadronization for doubly heavy baryons. The two heavy quarks in the baryon are approximated as a scalar or axial-vector diquark described by a heavy diquark effective theory. The gluon dynamics are represented by a NJL-Model interaction for the heavy diquarks and light quarks, which leads to an effective action of the baryon fields after the quark and diquark fields are integrated out. This effective action for doubly heavy baryon includes the electromagnetic and electroweak interactions, as well as the interaction with light mesons. We also verify the Ward-Takahashi identity at the baryon level, obtain the Isgur-Wise function for weak transitions, and calculate the strong coupling constant of the doubly heavy baryon and pion. Numerical studies are also performed.
↳ hep-phnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Role of chiral two-body currents in 6Li magnetic properties in light of a new precision measurement with the relative self-absorption technique

Precision measurement of 210Bi β-spectrum

Two-photon decays and transition form factors of π0, η, and η′ in large-Nc​ chiral perturbation theory

Statistical Behavior of Lepton Pair Spectrum in Drell-Yan Process and Signal from Quark-Gluon Plasma in High Energy Collisions

Solutions to Problems at Les Houches Summer School on EFT

Hadronization of heavy diquark and light quark within NJL-Model

Affiliations

Role of chiral two-body currents in $^{6}$ Li magnetic properties in light of a new precision measurement with the relative self-absorption technique

Precision measurement of $^{210}$ Bi $β$ -spectrum

Two-photon decays and transition form factors of $π^{0}$ , $η$ , and $η^{'}$ in large- $N_{c}$ chiral perturbation theory