![Resonance Parameters of the [rho]-meson from Lattice QCD PDF](https://books.google.com/books/content/images/frontcover/27-GzQEACAAJ?fife=w150-h200)
Author: Xu FengPublisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Resonance Parameters of the [rho]-meson from Lattice QCD
![Resonance Parameters of the [rho]-meson from Lattice QCD PDF](https://books.google.com/books/content/images/frontcover/27-GzQEACAAJ?fife=w80-h100)
Author: Xu FengResonance Parameters of the Rho-Meson from Lattice QCD.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
We perform a non-perturbative lattice calculation of the P-wave pion-pion scattering phase in the rho-meson decay channel using two flavors of maximally twisted mass fermions at pion masses ranging from 480 MeV to 290 MeV. Making use of finite-size methods, we evaluate the pion-pion scattering phase in the center-of-mass frame and two moving frames. Applying an effective range formula, we find a good description of our results for the scattering phase as a function of the energy covering the resonance region. This allows us to extract the rho-meson mass and decay width and to study their quark mass dependence.
Rho Resonance Parameters from Lattice QCD.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
We perform a high-precision calculation of the phase shifts for $\pi$-$\pi$ scattering in the I = 1, J = 1 channel in the elastic region using elongated lattices with two mass-degenerate quark favors ($N_f = 2$). We extract the $\rho$ resonance parameters using a Breit-Wigner fit at two different quark masses, corresponding to $m_{\pi} = 226$MeV and $m_{\pi} = 315$MeV, and perform an extrapolation to the physical point. The extrapolation is based on a unitarized chiral perturbation theory model that describes well the phase-shifts around the resonance for both quark masses. We find that the extrapolated value, $m_{\rho} = 720(1)(15)$MeV, is significantly lower that the physical rho mass and we argue that this shift could be due to the absence of the strange quark in our calculation.
Lattice QCD at the Physical Point
Author: Thibaut MétivetPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The formalism of Quantum Chromodynamics on the lattice (or Lattice QCD) allows to perform ab-initio non-perturbative studies of strong-interaction driven processes, as it provides both a covariant regularisation of the theory of QCD and a natural framework for numerical computations. In this work, after a review of the main features of QCD and a step-by-step presentation of our discretization of QCD on a lattice, we undertake detailed studies of two problems of hadronic physics: the phenomenon of resonant scattering and the structure of the nucleon. The lattice calculations are performed with the Budapest-Marseille-Wuppertal Collaboration's 2+1-flavour gauge configurations, which give access to a wide range of lattice spacings, volumes and quarks masses, thereby allowing to study the sensibility of our results on these parameters, and to perform a complete continuum extrapolation. These configurations include dynamical quarks, and use a clover-improved Wilson QCD action. To investigate the scattering of particles on the lattice, we set up a Lüscher analysis for the emblematic case of pion-pion scattering in the channel of the rho meson resonance. We analyse our data with a variational generalized eigenvalue method, and give an in-depth calculation of the scattering phase-shifts and the corresponding resonance parameters, with a full control of the systematic errors. Our results provide an important step for lattice studies of scattering states, as they are the first to be performed at the physical pion mass, where one can see the actual decay of the rho into two pions. The obtained rho meson parameters are in good agreement with the experimental values, and consistent with a weak pion mass dependence of the coupling between the rho and two pions. As for our probe of the structure of the nucleon, we present a complete extraction of the electroweak isovector form factors, with a comprehensive study of the electric charge squared radius and of the axial charge. Our analysis also feature data at the physical pion mass, which turns out to be crucial in order to perform safe extrapolations to the physical point, as the chiral perturbation theory predicts violent variations of these quantities near the massless-quarks point. Our calculation includes source and sink projections onto the nucleon state, as well as a combined fit method between the two-point and three-point correlation functions to control the contamination of our data by excited states. Although one would need more data to perform a high-accuracy determination of the nucleon radius and axial charge at the physical point with a relevant estimation of the systematic errors, the results we obtain are in good agreement with the experiment and suggest that the excited-state effects are under control. Our analysis also highlights that gauge configurations ensembles near the physical pion mass and with large volumes must be used in order to extract accurate information about the nucleon structure from lattice calculations.
Determination Of?-resonance Parameters from Lattice QCD.
Author: Meson Resonances from Lattice QCD.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems.
Scattering Phase Shift for Elastic Two Pion Scattering and the Rho Resonance in Lattice QCD
Author: Simone GutzwillerA Lattice QCD Study of the Rho Resonance and the Timelike Pion Form Factor
Author: Felix Benjamin ErbenPhenomenology And Lattice Qcd - Proceedings Of The 1993 Uehling Summer School
Author: Sharpe Stephen RPublisher: World Scientific
ISBN: 981454938X
Category :
Languages : en
Pages : 340
Book Description
These six lecture courses provide the background necessary in the understanding of the application of lattice methods to phenomenology, and give examples of interesting applications. The first three introduce the necessary techniques: chiral perturbation theory, heavy quark effective field theory, and lattice gauge theory. The remaining three describe how these techniques are used, mainly in lattice simulations, in the study of interesting phenomenological questions: vacuum structure, finite temperature QCD, and electroweak matrix elements. What distinguishes this volume from others is its focus on providing the background necessary for us to understand the methods and the significance of lattice gauge theory research.
![Extracting the R63 [rho] Resonance from Lattice QCD Simulations at Small Quark Masses PDF](https://books.google.com/books/content/images/frontcover/2rRLQwAACAAJ?fife=w80-h100)
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