scholarly journals Properties of Zb(10610) and Zb(10650) from an analysis of experimental line shapes

2019 ◽  
Vol 202 ◽  
pp. 06012
Author(s):  
V. Baru ◽  
A. A. Filin ◽  
C. Hanhart ◽  
A. V. Nefediev ◽  
Q. Wang ◽  
...  
Keyword(s):  
Integral Equations ◽  
Goldstone Boson ◽  
Exchange Interactions ◽  
Meson Exchange ◽  
Eta Meson ◽  
Line Shapes ◽  
Experimental Line ◽  
Chi Squared ◽  
The One ◽  
Coupled Channel

The experimental line shapes available in the B$ \bar {B} $*, B*$ \bar {B} $*, hb(1P)π and hb(2P)π channels are analysed using a theoretical EFT-based framework manifestly consistent with unitarity and analyticity. The line shapes are calculated using a system of coupled channel integral equations with the potential consisting of the one-pion and one-eta meson exchange interactions from the lightest Goldstone boson octet as well as of several contact terms at leading and subleading orders which are adjusted to minimise the overall chi squared. The pole positions of the Zb(10610) and Zb(10650) are extracted for the best fits corresponding to χ2/d.o.f. of the order of one.

scholarly journals Molecular interpretation of the LHCb pentaquarks from an analysis of J/ψp spectrum

2022 ◽  
Vol 258 ◽  
pp. 04007
Author(s):  
Meng-Lin Du
Keyword(s):  
Spin Symmetry ◽  
Lhcb Collaboration ◽  
Exchange Potential ◽  
Mass Distributions ◽  
Line Shapes ◽  
Quark Spin ◽  
Heavy Quark Spin Symmetry ◽  
Molecular Interpretation ◽  
The One ◽  
Coupled Channel

A coupled-channel approach including the ΛcD¯(*) and ηcp channels in addition to the Σc(*)D¯(*) and J/ψp channels, as required by unitarity and heavy quark spin symmetry (HQSS), is applied to the hidden-charm pentaquark Pc states, i.e., Pc(4312), Pc(4440) and Pc(4457), discovered by LHCb Collaboration. It is demonstrated that to obtain cutoff independent results, the one-pion exchange potential in the multichannel systems is to be supplemented with next-leading order counter terms responsible for the S-wave-to-D-wave transitions. We show that the experimental data for the J/ψp mass distributions are fully in line with the ΣcD¯ and ΣcD¯* hadronic molecular interpretation of the Pc(4312) and Pc(4440)/Pc(4457), respectively. A narrow Σc*D¯ molecule around 4.38 GeV is required by the HQSS with the evidence for its existence seen in the J/ψp spectrum. Moreover, we predict the line shapes for the elastic and inelastic channels.

One Parameter Chi-squared Analysis

2019 ◽  
pp. 18-31
Author(s):  
Carey Witkov ◽  
Keith Zengel
Keyword(s):  
Curve Fitting ◽  
Physical Experiments ◽  
Fitting Method ◽  
Wide Range ◽  
Chi Squared ◽  
Measurement Uncertainties ◽  
Distributed Measurement ◽  
Curve Fitting Method ◽  
The One ◽  
Parameter Case

The chi-squared method for parameter estimation and model testing is developed for the one-parameter case of a line with a slope but no intercept. Curve fitting is motivated, and several methods for curve fitting are introduced. The chi-squared method is shown to be the optimal curve fitting method whenever Gaussian distributed measurement uncertainties and a model are present. The central limit theorem, which assures Gaussian distributed measurement uncertainties for a wide range of physical experiments, is introduced. End-of-chapter problems are included (with solutions in an appendix).

scholarly journals Electroweak fermion triangle loop contributions to the muon anomalous magnetic moment revisited

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Ken Sasaki
Keyword(s):  
Magnetic Moment ◽  
Top Quark ◽  
Anomalous Magnetic Moment ◽  
Ward Identity ◽  
Axial Vector ◽  
Goldstone Boson ◽  
Muon Anomalous Magnetic Moment ◽  
Feynman Gauge ◽  
Unitary Gauge ◽  
The One

Abstract The contribution to the muon anomalous magnetic moment from the fermion triangle loop diagrams connected to the muon line by a photon and a $Z$ boson is re-analyzed in both the unitary gauge and the ’t Hooft–Feynman gauge. With use of the anomalous axial-vector Ward identity, it is shown that the calculation in the unitary gauge exactly coincides with the one in the ’t Hooft–Feynman gauge. The part which arises from the ordinary axial-vector Ward identity corresponds to the contribution of the neutral Goldstone boson. For the top-quark contribution, the one-parameter integral form is obtained up to the order of $m_\mu^2/m_Z^2$. The results are compared with those obtained by the asymptotic expansion method.

THE SHAPES OF PHOTOELECTRON SATELLITE SPECTRA

2002 ◽  
Vol 09 (02) ◽  
pp. 1209-1212 ◽  
Author(s):  
V. G. YARZHEMSKY ◽  
V. I. NEFEDOV ◽  
M. YA. AMUSIA ◽  
L. V. CHERNYSHEVA
Keyword(s):  
Line Shape ◽  
Shape Parameters ◽  
Line Shapes ◽  
Peak Structure ◽  
Experimental Line

Line shapes of photoionization satellites are theoretically investigated. Calculations were carried out for the satellite states 1s2s(3S)3s(2S) and 3s3p5(1P)4s(2P) of Ne 1s and Ar 3p vacancies, respectively, created in photoionization. Theory excellently reproduces experimental line shape parameters of the first satellite and predicts the two-peak structure of the second.

The impact theory of spectral line shapes: a paradigm shift

2013 ◽  
Vol 91 (11) ◽  
pp. 879-895 ◽  
Author(s):  
A.D. May ◽  
W.-K. Liu ◽  
F.R.W. McCourt ◽  
R. Ciuryło ◽  
J. Sanchez-Fortún Stoker ◽  
...  
Keyword(s):  
Spectral Line ◽  
Line Shape ◽  
Paradigm Shift ◽  
Wigner Distribution ◽  
Kinetic Equations ◽  
Line Profiles ◽  
Line Shapes ◽  
Experimental Line ◽  
Impact Theory ◽  
The Impact

An overview of the binary collision impact theory of spectral line shapes has been given to provide a unified statistical mechanical approach to line-shape theory, laser theory, nonlinear optics, and transport phenomena in dilute gases. The computation of spectral line profiles corresponding to those obtained from ultra-high-resolution spectral line-shape measurements requires numerical ab initio calculation of scattering amplitudes directly from the underlying dynamics of collisions between radiatively active molecules and their perturbers. The Wigner distribution function–density matrix is utilized to describe the kinetic theory of spectral line shapes and to discuss the various collisional processes that contribute to the kernel of kinetic equations. The influence of features of the potential energy surface on spectral parameters is also discussed, and the importance of comparing experimental line profiles directly with numerically computed line shapes obtained from reliable interaction potentials is emphasized. This contrasts sharply with the universal practice of comparing experimental line widths and shifts using some average or approximate theoretical scattering cross-sections and it contrasts sharply with fitting experimental profiles to some convenient analytical line-shape model; hence the phrase “a paradigm shift” in the title of this work.

scholarly journals Exotic molecular states in the decays of vector bottomonia

2019 ◽  
Vol 212 ◽  
pp. 02002
Author(s):  
V. Baru ◽  
E. Epelbaum ◽  
A. A. Filin ◽  
C. Hanhart ◽  
A. V. Nefediev ◽  
...  
Keyword(s):  
Short Range ◽  
Spin Symmetry ◽  
Radiative Decays ◽  
Recent Experimental Data ◽  
Line Shapes ◽  
Quantum Numbers ◽  
Quark Spin ◽  
Heavy Quark Spin Symmetry ◽  
Belle Ii ◽  
The One

The most recent experimental data for the decays of the vector bottomonium γ(10860) proceeding through the formation of the states Zb(10610) and Zb(10650) are analysed simultaneously using solutions of the Lippmann-Schwinger equations which respect constraints from unitarity and analyticity. The interaction potential in the open-bottom channels $ {B^{(*)}}{\bar B^*} $ contains short-range interactions as well as the one-pion exchange; both types of the interaction are taken into account fully nonperturbatively. This way, all parameters of the interaction are fixed directly from the data and the pole positions for the Zb’s are determined as a prediction. In particular, both Zb states are found to be described by resonance poles located on the unphysical Riemann sheets in the vicinity of the corresponding thresholds. The heavy quark spin symmetry (HQSS) is employed to predict, in a parameter-free way, the pole positions and the line shapes in the elastic and inelastic channels for the Zbs’ spin partner states WbJ with the quantum numbers J++ (J = 0, 1, 2). Such spin partners can be produced in radiative decays of the vector bottomonium Υ(10860) and are expected to be detected in the Belle-II experiment.

EXACT WAVEFUNCTION OF THE ONE-DIMENSIONAL DOUBLE-EXCHANGE MODEL WITH ONE ELECTRON

2012 ◽  
Vol 26 (30) ◽  
pp. 1250154 ◽  
Author(s):  
KYOHEI NAKANO ◽  
ROBERT EDER ◽  
YUKINORI OHTA
Keyword(s):  
Single Particle ◽  
Double Exchange ◽  
Exchange Interactions ◽  
Exchange Model ◽  
Particle Spectrum ◽  
Lower Edge ◽  
One Dimensional ◽  
Mobile Electron ◽  
Spin Excitations ◽  
The One

We study the one-dimensional double-exchange model with L localized spins and one mobile electron. We solve the Schrödinger equation analytically and obtain the energies and wavefunctions for all the eigenstates with spin S = (l-1)/2 exactly. As an application, we compute the single-particle Green's function. We show that, for vanishing exchange interactions between localized spins, the single-particle spectrum is entirely incoherent and the lowest band has an infinite band mass, i.e., the single electron is localized due to its interaction with the spin excitations. For nonvanishing exchange interactions between localized spins, the lower edge of the spectrum acquires a dispersion but the spectrum remains incoherent with no well-defined quasiparticle peak.

Resonance properties from a coupled channel meson exchange model

2009 ◽  
Vol 33 (12) ◽  
pp. 1273-1278 ◽  
Author(s):  
M Döring ◽  
C Hanhart ◽  
Huang Fei ◽  
S Krewald ◽  
U.-G Meißner
Keyword(s):  
Exchange Model ◽  
Meson Exchange ◽  
Resonance Properties ◽  
Coupled Channel
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