Investigating the low-energy structure! of the nucleon with relativistic! chiral effective field theory

Transcription

1 Investigating the low-energy structure! of the nucleon with relativistic! chiral effective field theory Jose Manuel Alarcón! Cluster of Excellence PRISMA, Institut für Kernphysik Johannes Gutenberg Universität, Mainz

2 Biographical presentation

3 Biographical presentation Born in 1983 in Cartagena in the Region of Murcia (Spain). In 21 I started my studies in Physics at the University of Murcia. In 25 I received the 1st prize in the physics contest Celebrando la Física organized by the University of Murcia. In 26 I finished them with the best grades, receiving a special prize for it (Premio extraordinario fin de carrera). From 26 to 27 I did the Master of Advanced Physics specialized in theoretical physics at the University of Valencia. In 27 I defended my Master Thesis at the University of Valencia, receiving the maximum grade. In 27 I started to work on my thesis under the supervision of Prof. Jose Antonio Oller, at the University of Murcia. Topic: Relativistic formulations of chiral EFT with baryons. 3/18

4 Biographical presentation In 212 I defended my thesis, entitled Baryon Chiral Perturbation Theory in its manifestly covariant forms and the study of the πν dynamics & On the Y(2175) resonance. It was rated with the best mark (Sobresaliente Cum Laude). Thesis awarded with the Premio extraordinario de doctorado, given to the best thesis in physics defended in the period at the University of Murcia. In July 212 I started to work in the group of Prof. Marc Vanderhaeghen at the Johannes Gutenberg University, Mainz. Working with Dr. Vladimir Pascalutsa applying the relativistic formalism used in my thesis to processes involving electromagnetic probes (Compton and pion photo- and electroproduction). 4/18

5 Research topics

6 Research topics Application of relativistic chiral EFT with baryons to fundamental nuclear reactions: Understanding of the chiral dynamics of the hadronic processes at low energies. Insight into the internal structure of the nucleon. πν scattering. Fundamental hadronic reaction involving one baryon. Not completely understood in the context of chiral dynamics Disagreement with dispersive approaches [Becher and Leutwyler, JHEP (21)] (is BChPT reliable?). Information about the internal scalar structure of the nucleon Important hadronic uncertainty in direct detection of DM [Bottino, Donato, Fornengo and Scopel, Astropart. Phys. 13, (2); Astropart. Phys. 18, (22)] [Ellis, Olive and Savage PRD 77, (28)]. Formation of elements needed for life [Berengut et. al., PRD 87, (213)]. N 6/18

7 Research topics The two manifest Lorentz invariant schemes were used: Infrared Regularization (IR) and Extended-On-Mass-Shell (EOMS). Conclusions [Alarcón, Martin Camalich and Oller, Ann. of Phys. 336 (213)]: At low energies above threshold IR, EOMS as well as Heavy Baryon ChPT give very similar results. The inclusion of the Δ(1232) makes a difference in the prediction of the phenomenology at low energies EOMS is clearly the best. S31 P31 P s (GeV) s (GeV) s (GeV) S11 P11 P s (GeV) s (GeV) s (GeV) EOMS + Δ(1232): Convergence in all observables. Agreement with the dispersive approaches BChPT is reliable! Phenomenological extraction of: Scattering lengths/volumes. Pion-nucleon coupling ( g N ). Pion-nucleon sigma term ( N ). 7/18

8 Research topics S31 P31 P33 Unitarization techniques are important in the extension to the strange-quark sector. We showed in [Alarcón, Martin Camalich and Oller, Ann. of Phys. 336 (213)] that EOMS gives the best results in SU(2) s (GeV) s (GeV) s (GeV) S11 P11 P s (GeV) s (GeV) s (GeV) EOMS + N/D IR + N/D HB + IAM Improve the analysis of the meson-baryon spectroscopy in the SU(3) sector [Alarcón, Martin Camalich and Oller, Ann. of Phys. 336 (213)] [Alarcón, Martin Camalich, Oller and Alvarez-Ruso, PRC 83 (211)] [Gomez Nicola, Nieves, Pelaez, Ruiz Arriola, PRD 69 (24)] Accurate determination of the Λ(145) poles. 8/18

9 Research topics Relativistic baryon chiral EFT with electromagnetic probes: Forward VVCS. Pion photo- and electroproduction. Learn about the internal electromagnetic structure of the nucleon. Proton LO HB NLO HB Γ p 1 4 fm p LT LO Rel. BChPT Q 2 GeV 2 BChPT+Δ 1 4 fm Q 2 GeV 2 MAID Δ contribution too large!!! Neutron Γ n 1 4 fm NLO HB Q 2 GeV 2 n LT 1 4 fm 4 IR-BChPT Q 2 GeV 2 LO HB JLab future data Hall A and B [Karl Slifer, Mainz] No n LT puzzle! [Korchelev and Oh, PRD 85 (212)] 9/18

10 Research topics In forward VVCS only a combination of scalar and spin polarizabilities are accesible Scalar E1 + M1. Spin ( E1E1 + M1M1 + M1E2 + E1M2 ). We are working on a set of sum rules to disentangle this combination [Alarcón, Lensky, Pascalutsa and Vanderhaeghen (Work on progress).] M1 from the Q 2 dependence of the photoabsorption cross sections. For the spin polarizabilities is not clear yet. The sum rules are being checked with relativistic baryon chiral EFT. Only the relativistic approach can be used Preserves analytical properties 1/18

11 Research topics VVCS and LO electroproduction calculation was used to calculate the polarizabilities contribution to the μη Lamb shift. Chiral EFT has the symmetries of QCD at low energies. Predictive. [Alarcón, Lensky and Pascalutsa, arxiv: Submitted to EPJ C] Marty- Nevado & Carlson & Birse & Gorchtein Pachucki nenko Pineda Vanderhaeghen McGovern et al. LO-B PT (µev) [1] [2] [3] [4] [5] [6] [this work] E (subt) 2S (1.9) 4.2(1.) 2.3(4.6) a 3. E (inel) 2S (5) 12.7(5) b 13.(6) 5.2 E (pol) 2S 12(2) (2.4) 8.5(1.1) 15.3(5.6) 8.2( ) a adjusted value; the original value of Ref. [6], +3.3, is based on a di erent decomposition into the elastic and polarizability contributions. b taken from Ref. [4]. [1] K. Pachucki, Phys. Rev. A 6, 3593 (1999). [2] A. P. Martynenko, Phys. Atom. Nucl. 69, 139 (26). [3] D. Nevado and A. Pineda, Phys. Rev. C 77, 3522 (28). [4] C. E. Carlson and M. Vanderhaeghen, Phys. Rev. A 84, 212 (211). [5] M. C. Birse and J. A. McGovern, Eur. Phys. J. A 48, 12 (212). [6] M. Gorchtein, F. J. Llanes-Estrada and A. P. Szczepaniak, Phys. Rev. A 87, 5251 (213). Agreement with phenomenological extractions. Understand the role of the Δ(1232) in μη Lamb shift. Explain the HB result 11/18

12 Research topics VVCS and LO electroproduction calculation was used to calculate the polarizabilities contribution to the μη Lamb shift. Chiral EFT has the symmetries of QCD at low energies. Predictive. [Alarcón, Lensky and Pascalutsa, arxiv: Submitted to EPJ C] Marty- Nevado & Carlson & Birse & Gorchtein Pachucki nenko Pineda Vanderhaeghen McGovern et al. LO-B PT (µev) [1] [2] [3] [4] [5] [6] [this work] E (subt) 2S (1.9) 4.2(1.) 2.3(4.6) a 3. E (inel) 2S (5) 12.7(5) b 13.(6) 5.2 E (pol) 2S 12(2) (2.4) 8.5(1.1) 15.3(5.6) 8.2( ) a adjusted value; the original value of Ref. [6], +3.3, is based on a di erent decomposition into the elastic and polarizability contributions. b taken from Ref. [4]. [1] K. Pachucki, Phys. Rev. A 6, 3593 (1999). [2] A. P. Martynenko, Phys. Atom. Nucl. 69, 139 (26). [3] D. Nevado and A. Pineda, Phys. Rev. C 77, 3522 (28). [4] C. E. Carlson and M. Vanderhaeghen, Phys. Rev. A 84, 212 (211). [5] M. C. Birse and J. A. McGovern, Eur. Phys. J. A 48, 12 (212). [6] M. Gorchtein, F. J. Llanes-Estrada and A. P. Szczepaniak, Phys. Rev. A 87, 5251 (213). Agreement with phenomenological extractions. Understand the role of the Δ(1232) in μη Lamb shift. Explain the HB result 11/18

13 Research topics!!!!!! Pion photo- and electroproduction with Δ(1232). Relativistic chiral EFT with the Δ(1232) gave important results in: Compton [Lensky and Pascalusta EPJ C 65, (21)]. πν scattering [Alarcón, Martin Camalich and Oller, Ann. of Phys. 336 (213)]. Breaking of the ChPT description of the p! p too close to the production threshold [Fernandez-Ramirez and Bernstein, PLB 253 (213)]. Excellent test for the chiral dynamics of meson photoproduction. Not understood in the context of chiral symmetry (yet). We are including systematically the strong isospin breaking effects (for first time in the literature). Work on progress. Planned to be finished within the next six months. χ 2 /dof Empirical HBChPT U-HBChPT E max γ (MeV) [Fernandez-Ramirez and Bernstein, PLB 253 (213)] 12/18

14 Future Projects

15 Future projects Our VVCS and electroproduction calculations allow us to investigate: I p A Generalized GDH integrals and IA n. Spin structure functions g1 n, g p, g and g p 1 2 n 2 (measured in E8-27, Hall A). Moments of the integrals of the structure functions ChPT is suited for higher moments at low Q 2. 14/18

16 Future projects Our VVCS and electroproduction calculations allow us to investigate: I p A Generalized GDH integrals and IA n. Spin structure functions g1 n, g p, g and g p 1 2 n 2 (measured in E8-27, Hall A). Moments of the integrals of the structure functions ChPT is suited for higher moments at low Q 2. Z x Example: Cornwall-Norton moment d 2 (Q 2 )=2 dx x 2 [g 1 (x, Q 2 )+ 3 2 g 2(x, Q 2 )] ChPT [Courtesy of Karl Slifer] 14/18

17 Future projects Our VVCS and electroproduction calculations allow us to investigate: I p A Generalized GDH integrals and IA n. Spin structure functions g1 n, g p, g and g p 1 2 n 2 (measured in E8-27, Hall A). Moments of the integrals of the structure functions ChPT is suited for higher moments at low Q 2. Z x Example: Cornwall-Norton moment d 2 (Q 2 )=2 dx x 2 [g 1 (x, Q 2 )+ 3 2 g 2(x, Q 2 )] LO ChPT result (improvable through the inclusion of the Δ(1232)) ChPT [Courtesy of Karl Slifer] 14/18

18 Future projects Our VVCS and electroproduction calculations allow us to investigate: I p A Generalized GDH integrals and IA n. Spin structure functions g1 n, g p, g and g p 1 2 n 2 (measured in E8-27, Hall A). Moments of the integrals of the structure functions ChPT is suited for higher moments at low Q 2. Z x Example: Cornwall-Norton moment d 2 (Q 2 )=2 dx x 2 [g 1 (x, Q 2 )+ 3 2 g 2(x, Q 2 )] LO ChPT result (improvable through the inclusion of the Δ(1232)) Low Q 2 will be accesible by JLab data ChPT [Courtesy of Karl Slifer] 14/18

19 Future projects Extension of the relativistic approach to the strange-quark sector. SU(3) meson-baryon in relativistic chiral EFT. Study of the baryonic spectrum (unitarized). Pole properties of the Λ(145). Line-shape πσ from the new CLAS data [Moriya et al. (CLAS Collaboration) PRC 87 (213)]. Strangeness photoproduction. Unitarization plays a fundamental role. Relativistic (EOMS) approach gives the best results Not explored yet!!! 15/18

20 Summary and Conclusions

21 Summary and Conclusions Relativistic chiral EFT with explicit Δ(1232) has become a new an promising approach to investigate the nuclear structure (MENU213) [Lensky and Pascalusta EPJ C 65, (21)], [Alarcón, Martin Camalich and Oller, Ann. of Phys. 336 (213)], [Bernard, Epelbaum, Krebs and Meissner, PRD 87 (213)]. Crucial to achieve a major progress in understanding the scalar and electromagnetic structure of the nucleon. Much more possibilities to exploit. Further investigation of the electromagnetic structure. Extension to the strange-quark sector. Interesting for experimental programs at JLab. Many-body nuclear interactions (Nuclear Lattice EFT) 17/18

22 FIN

23 Spares

24 Future projects NN and many-body nuclear physics. Relativistic NN, 3N and 4N interactions. Nuclear Lattice EFT. Ab initio calculations of: Nuclear corrections to 2β decay. Neutrino detection. Properties of atomic nuclei. Capture reactions. Nuclear fusion. Equation of state of neutron matter.

25 Thorough analysis of the Oller, PRD 85 (212)]. Research topics N phenomenology [Alarcón, Martin Camalich and Big impact on direct detection of dark matter. KA85 -ChPT WI8 -ChPT EM6 -ChPT -atoms ( + p, p) a + + (1 3 M 1 ) -11(1) -1.2(3.3) 2.3(2.) -1.(9) [1] Baru, Hanhart, Hoferichter, Kubis, Nogga & Phillips, NPA 872 (211) [Gasser, Leutwyler & Sainio, PLB 253 (1991)] N = 59(7) MeV Compatible with updated phenomenology! The πν database was the origin of the different values of N : Old database Modern database N 45 MeV N 6 MeV Favoured by phenomenology

26 Future projects Q 2 dependence not satisfactory described by chiral EFT Γ p 1 4 fm p LT Q 2 GeV fm Q 2 GeV Γ n 1 4 fm n LT Q 2 GeV fm Q 2 GeV 2 New data from Hall A and B at JLab [Karl Slifer, Mainz] [Bernard, Epelbaum, Krebs and Meissner, PRD 87 (213)]. p LT not understood Δ(1232) dominant and possitive Contradicts MAID model. The problem seems to be in how the Δ(1232) is included. Our work will help to solve this issue [Alarcón, Lensky and Pascalutsa (Work on progress)]. 15/2