new trends in high-energy physics (experiment, phenomenology, theory) alushta, crimea, ukraine,...
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NEW TRENDS IN HIGH-ENERGY PHYSICS(experiment, phenomenology, theory)
Alushta, Crimea, Ukraine, September 23-29, 2013
Effects of the next-to-leading order terms in the chiral SU(3) Lagrangian on the S=-1 s-wave meson-baryon interactions
In collaboration with A. Ramos, A. Feijoo Aliau
Chiral Perturbation Theory:which is based on effective Lagrangian with hadron d.o.f.,which respects the symmetries of QCD, in particular chiral symmetry
Perturbative QCD, with quark and gluon d.o.f., works well at high energies and high momentum transfers, but fails to describe dynamics of hadrons at low energies
Chiral Perturbation Theory:which is based on effective Lagrangian with hadron d.o.f.,which respects the symmetries of QCD, in particular chiral symmetry
Perturbative QCD, with quark and gluon d.o.f., works well at high energies and high momentum transfers, but fails to describe dynamics of hadrons at low energies
The spontaneous chiral symmetry breaking causes the appearance of the Nambu–Goldstone (NG) bosons as the light pseudoscalar mesons and the dynamical mass generation of hadrons.
Baryon meson interaction at lowest order
WT: Weim
berg
-Tomozawa term
WT baryon meson interaction
WT baryon meson interaction
The only model parameter is pion decay constant, f
En real calculations it is usually taken
in order to partly simulate effects of higher order corrections
Perturbative QCD, with quark and gluon d.o.f., works well at high energies and high momentum transfers, but fails to describe dynamics of hadrons at low energies
Chiral Perturbation Theory:which is based on effective Lagrangian with hadron d.o.f.,which respects the symmetries of QCD, in particular chiral symmetry
Unitary extension of Chiral Perturbation TheoryThe pioneering work -- Kaiser, Siegel, Weise , NP A594 (1995) 325
Máster Interuniversitario de Física Nuclear (UB)
System of thealgebraic equations
Lippmann-Schwinger equation
On shell factorization
Loop function
Boost in unitary extensions of chiral perturbation theory
1995-2003: Kaiser, Oset, Ramos, Oller, Meissner, Jido, Hosaka, Garcia-Recio, Vicente Vacas
Λ(1405) as a dynamically generated resonance
Jones, Dalitz and Horgan, Nucl. Phys. B129 (1977) 45 – Λ(1405) is dynamical generated
Boost in unitary extensions of chiral perturbation theory
Jones, Dalitz and Horgan, Nucl. Phys. B129 (1977) 45 – Λ(1405) is dynamical generated
1995-2003: Kaiser, Oset, Ramos, Oller, Meissner, Jido, Hosaka, Garcia-Recio, Vicente Vacas
Λ(1405) as a dynamically generated resonance
Surprisingly there are two poles in the neighborhood of the Λ(1405) both contributing to the final experimental invariant mass distribution
Mass ~ 1390 MeVWidth ~ 130 MeV
Mass ~ 1425 MeVWidth ~ 30 MeV
0Kp
000 pK
)1405(The observed shapes are in good agreement with corresponding chiral unitarity model calculations:
This combined study gives the first experimental evidence of the two-pole nature of the Λ(1405)
0Kp
Crystall Ball Collaboration data from 000 pK
versus
Thomas et al., NP B 56 (1973) 15
(Width ~ 60 MeV)
(Width ~ 38 MeV)
Magas, Oset, R
amos,
PRL 95 (2005) 052301;
also presented at Crimea’2005
Recent Publications:
- B. Borasoy, R. Nißler, W. Wiese, Eur. Phys. J. A25 (2005) 79
- Y. Ikeda, T. Hyodo, W. Wiese, Phys. Lett. B706 (2011) 63; Nucl. Phys. A881 (2012) 98
- A. Feijoo Aliau, Master Thesis, U. of Barcelona (Nov 2012)
- Z.-H. Guo, J.A. Oller, Phys. Rev. C87 (2013) 035202
Chiral meson-baryon effective Lagrangian at NLO
Chiral meson-baryon effective Lagrangian at NLO
- is the symmetry breaking term
Chiral meson-baryon effective Lagrangian at NLO
- is the symmetry breaking term
7 new parameters to be fixed:
Máster Interuniversitario de Física Nuclear (UB)
• WT, lowest order term
• Next – to – Leading Order term
Chiral meson-baryon effective Lagrangian at NLO
Máster Interuniversitario de Física Nuclear (UB)
At low energies
Chiral meson-baryon effective Lagrangian at NLO
• WT, lowest order term
• Next – to – Leading Order term
Máster Interuniversitario de Física Nuclear (UB)
Experimental data
- Cross sections for different channels
- Branching ratios
Máster Interuniversitario de Física Nuclear (UB)
Fitting parameters
- Decay constant f
- 7 parameters of the NLO Lagrangian:
- 10 subtracting constants 6 constants:isospin symmetry
Fitting parameters
[1] Borasoy, Nißler, Wiese, Eur. Phys. J. A25 (2005) 79
Máster Interuniversitario de Física Nuclear (UB)
• Branching ratios
Results
[1] Borasoy, Nißler, Wiese, Eur. Phys. J. A25 (2005) 79
Results
Results
These are particularly interesting for us, becausefor WT interaction
channels are very sensitive to the NLO terms in the Lagrangian
Also these channels are not included in the other fits!B. Borasoy, R. Nißler, W. Wiese, Eur. Phys. J. A25 (2005) 79Y. Ikeda, T. Hyodo, W. Wiese, Phys. Lett. B706 (2011) 63; Nucl. Phys. A881 (2012) 98Z.-H. Guo, J.A. Oller, Phys. Rev. C87 (2013) 035202
But studied in the phenomenological model of D. A. Sharov, V. L. Korotkikh, D. E. Lanskoy, Eur. Phys. J. A47 (2011) 109
- Missing contribution from the heavy high spin resonances
Máster Interuniversitario de Física Nuclear (UB)
In Ref. [Sharov, Korotkikh, Lanskoy, EPJ A47 (11) 109] , trying different combinations, the author conclude thatΣ(2030) and Σ(2250) give the better fit to the data
Work in progress
K. Nakayama, Youngseok Oh, H. Habertzettl, Phys. Rev. C74, 035205 (2006)K. Shing Man, Youngseok Oh, K. Nakayama,, Phys. Rev. C83, 055201 (2011)
The propagators of the spin-5/2 and -7/2 fermion fields
Conclusions
Chiral Perturbation Theory with unitarization in coupled channels is a very powerful technique to describe low energy hadron dynamics
Next – to – leading order calculations are now possible
are very interesting and important for fitting NLO parameters
NLO terms in the Lagrangian do improve agreement with data
Work in progress…