Lambda (1405) photoproduction based on chiral unitary model

Abstract

Recent CLAS data for the pi Sigma invariant mass distributions (line-shapes) in the gamma p -> K^+ pi Sigma reaction are theoretically investigated. The line-shapes have peaks associated with the Lambda(1405) excitation. Our model consists of gauge invariant photo-production mechanisms, and the chiral unitary model that gives the rescattering amplitudes where Lambda(1405) is contained. It is found that, while the pi Sigma line-shape data in the Lambda(1405) region are successfully reproduced by our model for all the charge states, the production mechanism is not so simple that we need to introduce parameters associated with short-range dynamics to fit the data. Our detailed analysis suggests that the nonresonant background contribution is not negligible, and its sizable effect shifts the Lambda(1405) peak position by several MeV. We also analyze the data using a Breit-Wigner amplitudes instead of those from the chiral unitary model. We find that the fitted Breit-Wigner parameters are closer to the higher pole position for Lambda(1405) of the chiral unitary model. This work sets a starting point for a fuller analysis in which line-shape as well as K^+ angular distribution data are simultaneously analyzed for extracting Lambda(1405) pole(s).

27 pages, 23 figures; published version, 4 figures added, some discussions added, typos corrected

References in corpus (5)

• Measurement of the Sigma pi photoproduction line shapes near the Lambda(1405)
• Lineshape of the Lambda(1405) Hyperon Measured Through its Sigma0 pion0 Decay
• Kaonic production of Lambda(1405) off deuteron target in chiral dynamics
• A gauge invariant chiral unitary framework for kaon photo- and electroproduction on the proton
• Lambda(1405) poles obtained from pi0-Sigma0 photoproduction data

Cited by in corpus (16)

• Threshold cusps and triangle singularities in hadronic reactions
• Role of a triangle singularity in the $\gamma p\to K^{+}\Lambda (1405)$ reaction
• Cross-channel constraints on resonant antikaon-nucleon scattering
• Hyperon resonances coupled to pseudoscalar- and vector-baryon channels
• Hadron Physics at J-PARC
• Photoproduction of $\Lambda (1405)$ with the $N^{\ast }$ and $t$-channel Regge contributions
• The role of the triangle singularity in $\Lambda (1405)$ production in the ${\pi }^{-}p\to K^0\pi \Sigma$ and $pp\to p{K}^{+}\pi \Sigma$ processes
• $\Lambda (1405)$ production in the process ${\chi }_{c0}(1P)\to \bar{\Lambda }\Sigma \pi$
• Faddeev approach to the reaction $K^{-}d\to \pi \Sigma n$ at $p_K=1$ GeV/c
• Theoretical study of the Lambda(1405) resonance in Xi_b^0 -> D^0 pi Sigma decay
• Photo- and electroproduction of $\Lambda (1405)$ via ${\gamma }^{(\ast )}p\to K^{+}{\pi }^{+}{\Sigma }^{-}$
• Singlet baryons in the graded symmetry approach to partially quenched QCD
• Trace of $\Lambda (1405)$ resonance in low energy $K^{-}+{}^3\mathrm{He}\to ({\pi }^0{\Sigma }^0)+d$ reaction
• Structure of $\Lambda$(1405) resonance and $\gamma p\to K^{+}+(\pi \Sigma {)}^0$ reaction
• Lessons from fitting the lowest order energy independent chiral based $\bar{K}N$ potential to experimental data
• Producing $\Lambda (1405)$ and $\Lambda (1520)$ in ${\pi }^{-}p$ reaction to explore their inner structures