The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform

Laurent Lellouch - One of the best experts on this subject based on the ideXlab platform.

  • Up and Down Quark masses and corrections to Dashen's theorem from lattice QCD and quenched QED
    Proceedings of 34th annual International Symposium on Lattice Field Theory — PoS(LATTICE2016), 2017
    Co-Authors: Lukas Varnhorst, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo
    Abstract:

    We present a determination of the corrections to Dashen's theorem and of the individual up and Down Quark masses from a lattice calculation based on quenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings Down to 0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashens's theorem we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4) \, \mbox{MeV}$ and $m_d=4.67(6)(5)(4) \, \mbox{MeV}$ in the $\overline{\mbox{MS}}$ scheme at $2 \, \mbox{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.
    Physical review letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo, Th. Lippert, Lukas Varnhorst
    Abstract:

    In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. Our ensembles include 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
    Physical Review Letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Th. Lippert, K. k. Szabo, Lukas Varnhorst
    Abstract:

    In a previous letter (arXiv:1306.2287) we determined the isospin mass splittings of the baryon octet from a lattice calculation based on quenched QED and $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings Down to $0.054~\mathrm{fm}$, lattice sizes up to $6~\mathrm{fm}$ and average up-Down Quark masses all the way Down to their physical value. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. For the parameter which quantifies violations to Dashens's theorem, we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4)~\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\mathrm{MeV}$ in the $\bar{\mathrm{MS}}$ scheme at $2~\mathrm{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than $24$ standard deviations.

  • isospin splittings in the light baryon octet from lattice qcd and qed
    Physical Review Letters, 2013
    Co-Authors: Sz. Borsanyi, S. Durr, C. Hoelbling, Stefan Krieg, J. Frison, S. D. Katz, Zoltan Fodor, Thorsten Kurth, Laurent Lellouch
    Abstract:

    While electromagnetic and up-Down Quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here, we include these effects by adding them to valence Quarks in a lattice QCD calculation based on ${N}_{f}=2+1$ simulations with five lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-Down Quark mass difference. Our results for the total splittings are in good agreement with experiment.

  • Isospin splittings in the light baryon octet from lattice QCD and QED
    Physical Review Letters, 2013
    Co-Authors: Sz. Borsanyi, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, J. Frison, S. D. Katz, Th. Kurth, Th. Lippert
    Abstract:

    While electromagnetic and up-Down Quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here we include these effects by adding them to valence Quarks in a lattice QCD calculation based on $N_f=2+1$ simulations with 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-Down Quark mass difference. Our results for the total splittings are in good agreement with experiment.

C. Hoelbling - One of the best experts on this subject based on the ideXlab platform.

  • Up and Down Quark masses and corrections to Dashen's theorem from lattice QCD and quenched QED
    Proceedings of 34th annual International Symposium on Lattice Field Theory — PoS(LATTICE2016), 2017
    Co-Authors: Lukas Varnhorst, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo
    Abstract:

    We present a determination of the corrections to Dashen's theorem and of the individual up and Down Quark masses from a lattice calculation based on quenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings Down to 0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashens's theorem we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4) \, \mbox{MeV}$ and $m_d=4.67(6)(5)(4) \, \mbox{MeV}$ in the $\overline{\mbox{MS}}$ scheme at $2 \, \mbox{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.
    Physical review letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo, Th. Lippert, Lukas Varnhorst
    Abstract:

    In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. Our ensembles include 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
    Physical Review Letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Th. Lippert, K. k. Szabo, Lukas Varnhorst
    Abstract:

    In a previous letter (arXiv:1306.2287) we determined the isospin mass splittings of the baryon octet from a lattice calculation based on quenched QED and $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings Down to $0.054~\mathrm{fm}$, lattice sizes up to $6~\mathrm{fm}$ and average up-Down Quark masses all the way Down to their physical value. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. For the parameter which quantifies violations to Dashens's theorem, we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4)~\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\mathrm{MeV}$ in the $\bar{\mathrm{MS}}$ scheme at $2~\mathrm{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than $24$ standard deviations.

  • isospin splittings in the light baryon octet from lattice qcd and qed
    Physical Review Letters, 2013
    Co-Authors: Sz. Borsanyi, S. Durr, C. Hoelbling, Stefan Krieg, J. Frison, S. D. Katz, Zoltan Fodor, Thorsten Kurth, Laurent Lellouch
    Abstract:

    While electromagnetic and up-Down Quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here, we include these effects by adding them to valence Quarks in a lattice QCD calculation based on ${N}_{f}=2+1$ simulations with five lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-Down Quark mass difference. Our results for the total splittings are in good agreement with experiment.

  • Isospin splittings in the light baryon octet from lattice QCD and QED
    Physical Review Letters, 2013
    Co-Authors: Sz. Borsanyi, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, J. Frison, S. D. Katz, Th. Kurth, Th. Lippert
    Abstract:

    While electromagnetic and up-Down Quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here we include these effects by adding them to valence Quarks in a lattice QCD calculation based on $N_f=2+1$ simulations with 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-Down Quark mass difference. Our results for the total splittings are in good agreement with experiment.

Lukas Varnhorst - One of the best experts on this subject based on the ideXlab platform.

  • Up and Down Quark masses and corrections to Dashen's theorem from lattice QCD and quenched QED
    Proceedings of 34th annual International Symposium on Lattice Field Theory — PoS(LATTICE2016), 2017
    Co-Authors: Lukas Varnhorst, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo
    Abstract:

    We present a determination of the corrections to Dashen's theorem and of the individual up and Down Quark masses from a lattice calculation based on quenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings Down to 0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashens's theorem we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4) \, \mbox{MeV}$ and $m_d=4.67(6)(5)(4) \, \mbox{MeV}$ in the $\overline{\mbox{MS}}$ scheme at $2 \, \mbox{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.
    Physical review letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo, Th. Lippert, Lukas Varnhorst
    Abstract:

    In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. Our ensembles include 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
    Physical Review Letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Th. Lippert, K. k. Szabo, Lukas Varnhorst
    Abstract:

    In a previous letter (arXiv:1306.2287) we determined the isospin mass splittings of the baryon octet from a lattice calculation based on quenched QED and $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings Down to $0.054~\mathrm{fm}$, lattice sizes up to $6~\mathrm{fm}$ and average up-Down Quark masses all the way Down to their physical value. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. For the parameter which quantifies violations to Dashens's theorem, we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4)~\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\mathrm{MeV}$ in the $\bar{\mathrm{MS}}$ scheme at $2~\mathrm{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than $24$ standard deviations.

Z. Fodor - One of the best experts on this subject based on the ideXlab platform.

  • Up and Down Quark masses and corrections to Dashen's theorem from lattice QCD and quenched QED
    Proceedings of 34th annual International Symposium on Lattice Field Theory — PoS(LATTICE2016), 2017
    Co-Authors: Lukas Varnhorst, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo
    Abstract:

    We present a determination of the corrections to Dashen's theorem and of the individual up and Down Quark masses from a lattice calculation based on quenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings Down to 0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashens's theorem we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4) \, \mbox{MeV}$ and $m_d=4.67(6)(5)(4) \, \mbox{MeV}$ in the $\overline{\mbox{MS}}$ scheme at $2 \, \mbox{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.
    Physical review letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Kalman K. Szabo, Th. Lippert, Lukas Varnhorst
    Abstract:

    In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. Our ensembles include 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm, and average up-Down Quark masses all the way Down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

  • Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
    Physical Review Letters, 2016
    Co-Authors: Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, Antonin Portelli, A. Sastre, Th. Lippert, K. k. Szabo, Lukas Varnhorst
    Abstract:

    In a previous letter (arXiv:1306.2287) we determined the isospin mass splittings of the baryon octet from a lattice calculation based on quenched QED and $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings Down to $0.054~\mathrm{fm}$, lattice sizes up to $6~\mathrm{fm}$ and average up-Down Quark masses all the way Down to their physical value. Using the same data we determine here the corrections to Dashen's theorem and the individual up and Down Quark masses. For the parameter which quantifies violations to Dashens's theorem, we obtain $\epsilon=0.73(2)(5)(17)$, where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light Quark masses we obtain, $m_u=2.27(6)(5)(4)~\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\mathrm{MeV}$ in the $\bar{\mathrm{MS}}$ scheme at $2~\mathrm{GeV}$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than $24$ standard deviations.

  • Isospin splittings in the light baryon octet from lattice QCD and QED
    Physical Review Letters, 2013
    Co-Authors: Sz. Borsanyi, S. Durr, Z. Fodor, C. Hoelbling, Stefan Krieg, Laurent Lellouch, J. Frison, S. D. Katz, Th. Kurth, Th. Lippert
    Abstract:

    While electromagnetic and up-Down Quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here we include these effects by adding them to valence Quarks in a lattice QCD calculation based on $N_f=2+1$ simulations with 5 lattice spacings Down to 0.054 fm, lattice sizes up to 6 fm and average up-Down Quark masses all the way Down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-Down Quark mass difference. Our results for the total splittings are in good agreement with experiment.

Jianjun Yang - One of the best experts on this subject based on the ideXlab platform.

  • up and Down Quark contributions to spin content of lambda from fragmentation
    arXiv: High Energy Physics - Phenomenology, 2001
    Co-Authors: Jianjun Yang
    Abstract:

    We check the $u$ and $d$ Quark contributions to the spin content of the $\Lambda$ by means of the $q\to\Lambda$ fragmentation and find that the $u$ and $d$ Quarks of the $\Lambda$ are likely positively polarized. The parton distributions in the $\Lambda$ are given by a successful statistical model which can reproduce and correlate a vast body of polarized and unpolarized structure function and parton distribution data of the nucleon. With the Gribov-Lipatov relation between the Quark distributions and fragmentation functions, the longitudinal spin transfer for the $\Lambda$ production in the polarized charged lepton deep inelastic scattering (DIS) process and the $\Lambda$-polarization in the neutrino (antineutrino) DIS process are predicted. The available experimental data suggests that the $u$ and $d$ Quark contributions to the spin of the $\Lambda$ are positive. In addition, our results provide a collateral evidence for the SU(3) symmetry breaking in hyperon semileptonic decays of the octet baryons, which is very important for a deeper understanding of the proton 'spin crisis'.

  • up and Down Quark contributions to spin content of λ from fragmentation
    Physics Letters B, 2001
    Co-Authors: Jianjun Yang
    Abstract:

    Abstract We check the u and d Quark contributions to the spin content of the Λ by means of the q → Λ fragmentation and find that the u and d Quarks of the Λ are likely positively polarized. The parton distributions in the Λ are given by a successful statistical model which can reproduce and correlate a vast body of polarized and unpolarized structure function and parton distribution data of the nucleon. With the Gribov–Lipatov relation between the Quark distributions and fragmentation functions, the longitudinal spin transfer for the Λ production in the polarized charged lepton deep inelastic scattering (DIS) process and the Λ -polarization in the neutrino (antineutrino) DIS process are predicted. The available experimental data suggests that the u and d Quark contributions to the spin of the Λ are positive. In addition, our results provide a collateral evidence for the SU(3) symmetry breaking in hyperon semileptonic decays of the octet baryons, which is very important for a deeper understanding of the proton ‘spin crisis’.