scholarly journals Results for the mass difference between the long- and short-lived K mesons for physical quark masses

2019 ◽  
Author(s):  
Bigeng Wang
Keyword(s):  
Mass Difference ◽  
Quark Masses ◽  
K Mesons

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

Chiral Symmetry

2019 ◽  
pp. 217-230
Author(s):  
Michael E. Peskin
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Chiral Symmetry ◽  
Goldstone Boson ◽  
Spontaneous Breaking ◽  
Quark Masses ◽  
Zero Mass ◽  
K Mesons ◽  
The Masses

This chapter introduces chiral symmetry, the extra symmetry that QCD acquires when the masses of quarks are set to zero. It introduces the concept of spontaneous symmetry breaking and explains the spontaneous breaking of chiral symmetry in QCD. It introduces the concept of a Goldstone boson, a particle that has zero mass as the result of spontaneous symmetry breaking, and explains how this concept explains properties of the pi and K mesons and allows us to determine the underlying values of the quark masses.

BARYON MAGNETIC MOMENTS AND SPIN DEPENDENT QUARK FORCES

2002 ◽  
Vol 11 (01) ◽  
pp. 71-81
Author(s):  
GEORGE L. STROBEL
Keyword(s):  
Wave Function ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
Mass Difference ◽  
Wave Functions ◽  
Small Current ◽  
Axial Charge ◽  
Strange Quarks ◽  
Quark Masses ◽  
Quark Wave Function

The J=3/2 Δ, J=1/2 nucleon mass difference shows that quark energies can be spin dependent. It is natural to expect that quark wave functions also depend on spin. In the octet, such spin dependent forces lead to different wave functions for quarks with spin parallel or antiparallel to the nucleon spin. A two component Dirac equation wave function is used for the quarks assuming small current quark masses for the u and d quarks. Then, the neutron/proton magnetic moment ratio, the nucleon axial charge, and the spin content of the nucleon can all be simultaneously fit assuming isospin invariance between the u and d quarks, but allowing for spin dependent forces. The breakdown of the Coleman–Glashow sum rule for octet magnetic moments follows naturally in this Dirac approach as the bound quark energy also effects the magnetic moment. Empirically the bound quark energy increases with the number of strange quarks in the system. Allowing the strange quark wave function similar spin dependence predicts the magnetic moments of the octet, in close agreement with experiment. Differences between the octet and decuplet magnetic moments are also explained immediately with spin dependent wave functions.

scholarly journals The KL - KS Mass Difference

2018 ◽  
Vol 175 ◽  
pp. 13017 ◽  
Author(s):  
Ziyuan Bai ◽  
Norman H. Christ ◽  
Christopher T. Sachrajda
Keyword(s):  
Mass Difference ◽  
Theoretical Framework ◽  
Quark Masses ◽  
The Status

We review the status of the RBC-UKQCD collaborations’ computations of the KL-KS mass difference. After a brief discussion of the theoretical framework which had been developed previously by the collaboration, we describe our latest computation, performed at physical quark masses, and present our preliminary result mKL - mKS = (5.5 ± 1.70) × 10-12 MeV.

scholarly journals Simulation of an ensemble of Nf = 2 + 1 + 1 twisted mass cloverimproved fermions at physical quark masses

2018 ◽  
Vol 175 ◽  
pp. 02003 ◽  
Author(s):  
Jacob Finkenrath ◽  
Constantia Alexandrou ◽  
Simone Bacchio ◽  
Panagiotis Charalambous ◽  
Petros Dimopoulos ◽  
...  
Keyword(s):  
Pion Mass ◽  
Mass Difference ◽  
Target System ◽  
General Strategy ◽  
Decay Constants ◽  
Quark Masses ◽  
Twisted Mass ◽  
Kaon Mass ◽  
Physical Mass ◽  
The Moment

We present a general strategy aimed at generating Nf = 2+1+1 configurations with quarks at their physical mass using maximally twisted mass fermions to ensure automatic O(a) improvement, in the presence of a clover term tuned to reduce the charged to neutral pion mass difference. The target system, for the moment, is a lattice of size 643 × 128 with a lattice spacing a ~ 0:08 fm. We show preliminary results on the pion and kaon mass and decay constants.

Mass difference of neutral K mesons

1961 ◽  
Vol 22 (6) ◽  
pp. 1160-1170 ◽  
Author(s):  
V. L. Fitch ◽  
P. A. Piroué ◽  
R. B. Perkins
Keyword(s):  
Mass Difference ◽  
K Mesons

THE CALCULATION OF THE ELECTROMAGNETIC π+−π0 MASS DIFFERENCE WITHIN QCD

1992 ◽  
Vol 07 (26) ◽  
pp. 6523-6535 ◽  
Author(s):  
A.A. PIVOVAROV
Keyword(s):  
Reasonable Agreement ◽  
Sum Rules ◽  
Chiral Limit ◽  
Mass Difference ◽  
Electromagnetic Mass ◽  
Qcd Sum Rules ◽  
K Mesons

The electromagnetic π+−π0 mass difference is calculated with QCD sum rules technique in the chiral limit. The obtained result Δmπ=4.4±1.1 MeV is in reasonable agreement with the experimental value (Δmπ)exp=4.43±0.03 MeV. The developed technique can be also applied to the determination of the electromagnetic mass difference of K mesons.

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