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Javier Roca Maza – Curriculum Vitae - unimi.it · JavierRoca Maza Curriculum Vitae Personal...
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Javier Roca Maza Curriculum Vitae Personal Information Family name Roca Maza Given name Javier Address Via Pacini 26, I-20131 Milano Cell Phone (+39) 338 117 00 94 e-mail [email protected] Date of birth 3rd of June 1978 Place of birth Barcelona Citizenship Spanish Passport number AAC464902 Expiration date 23rd of September 2020 Present position Assistant Professor (Ricercatore a Tempo Determinato) Institution University of Milan Physics Department Office Via Celoria 16, I-20133 Milano Sezione Fisica del Nucleo, LITA building 1st floor, room number A/1/C8 e-mail [email protected] Phone (+39) 02 503 17 290 Fax (+39) 02 503 17 487 Website www.mi.infn.it/~jroca/ Via Pacini 26 – Milano, Italy 20131 H (+39) 338 117 00 94 • T (+39) 02 503 17 290 B [email protected] • ˝ www.mi.infn.it/ jroca/ 1/17
Transcript of Javier Roca Maza – Curriculum Vitae - unimi.it · JavierRoca Maza Curriculum Vitae Personal...
Javier Roca MazaCurriculum Vitae
Personal InformationFamily name Roca MazaGiven name Javier
Address Via Pacini 26, I-20131 MilanoCell Phone (+39) 338 117 00 94
e-mail [email protected] of birth 3rd of June 1978Place of birth Barcelona
Citizenship SpanishPassportnumber
AAC464902
Expirationdate
23rd of September 2020
Present positionAssistant Professor (Ricercatore a Tempo Determinato)
Institution University of MilanPhysics Department
Office Via Celoria 16, I-20133 MilanoSezione Fisica del Nucleo, LITA building1st floor, room number A/1/C8
e-mail [email protected] (+39) 02 503 17 290
Fax (+39) 02 503 17 487Website www.mi.infn.it/~jroca/
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 1/17
Education2009 Course on Pedagogical Aptitude
Institution University of Barcelona, SpainPhD Thesis
2005–2010 University of Barcelona, SpainTitle Isospin asymmetry in stable and exotic nuclei
Supervisors Prof. Xavier Viñas i Gausí and Prof. Mario Centelles i AixalàGrade “Excel.lent Cum Laude”
Description Physical properties of nuclei, such as the mass, neutron and proton distributions,collective excitations, fission properties, etc. are influenced by the isospin dependenceof the nuclear strong interaction. The symmetry energy and its density dependenceaccount for the effects observed in nuclei with proton-neutron differences. Therefore,the accurate characterization of this property entails profound consequences instudying the nucleus. It also impacts on diverse areas such as nuclear astrophysics andtests of the Standard Model via atomic parity violation. The experimental situationwill change considerably within the next years. The advent of new techniques tosynthesize and perform experiments with exotic nuclei will allow this change. Thissituation have motivated the studies presented along this Thesis where some aspectsof the isospin dependence of the nuclear force have been investigated. Our aimwas to understand the effects that such dependence produce on different nuclearobservables of both, stable and exotic nuclei.
Stage From September to December 2007 at the Physics Department of the Florida StateUniversity. Collaboration project with Prof. Jorge Piekarewicz.
Advanced Studies Diploma Thesis2005–2007 University of Barcelona, Spain
Title Cooling by approximation to a N2 thermal bathSupervisor Prof. Eduard Vives
Grade “Excel.lent”Description Hardware and software set up of a cooling system by approximation to a nitrogen
thermal bath. That is a fully automatic device which allow the measurement ofdifferent thermodynamical properties of the material under study as a function ofthe temperature. From room temperature to nearly 77 K.
2005–2007 University of Barcelona, SpainTitle ESEN−Elastic Scattering of Electrons by Nuclei
Supervisor Prof. Francesc SalvatGrade “Excel.lent”
Description Modification of the ELSEPA code for the calculation of elastic electron scatteringby stable and exotic nuclei and analysis of scattering observables with modernmicroscopic nuclear mean-field models.
Master Degree in Physics2000–2004 University of Barcelona, Spain
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
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AverageGrade
“Notable”, 7.6 in a scale from 0 to 10
Experience2014–2018 Italian Qualification for Associate Professor in the area 02/A2–Theoretical physics
of fundamental interactions. Bibliomet ric indicators reported by the commission :
-the number of articles during the last 10 years normalized by the academic age was34-the number of citations during the last 10 years normalized by the academic agewas 59.6-the contemporary h index was 11
Reviewer2014–Present Journal of Physics G: Nuclear and Particle Physics
ISSN 1361-6471 (online), 0954-3899 (print)
2012–Present Referee of Physical Review CISSN 1089-490X (online), 0556-2813 (print)
2012–Present Nuclear Physics AISSN 0375-9474
Research2013–Present Assistant Professor (Ricercatore a Tempo Determinato)
Institution University of Milan, Physics Department
2012–2013 PostDoc position. Research Grant.Institution University of Milan, Physics Department
2010–2012 PostDoc position. Fellowship for foreign researchers.Institution Istituto Nazionale di Fisica Nucleare (INFN), Milan section
2010 PostDoc position. Contract (6 months).Institution University of Barcelona. Physics Department.
Teaching2013–2014 Co-supervisor of Master Thesis.Institution University of Milan
Student Valentina CraveiaTitle Elastic properties and collective modes of a neutron star crust (to be confirmed).
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
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2013 Co-supervisor of Bachelor Thesis.Institution University of MilanStudent Davide Basilico
Title Magnetic field effects on the composition of a neutron star outer crust (Italian).
2010–2011 Co-supervisor of Master Thesis.Institution University of MilanStudent Giacomo Pozzi
Title A Microscopic Model for the Collective Response in Odd N uclei.
2009 Teaching to the 2nd course of “ESO” (basic physics) during my Course on Peda-gogical Aptitude
Institution IES Les Corts, Barcelona, Spain
2008–2010 Teaching assistant for the course of Laboratori de Termodinàmica (Physics), Subjectof the degree in Physics
Institution University of Barcelona.
Awards2011 Special Mention in the Dissertation Award in Nuclear Physics (2009-2011) of the
Nuclear Physics Division of the European Physical Society.
Fellowships2012–2013 PostDoctoral type-A fellowship from the University of Milan
2010-2012 PostDoctoral fellowship for non-italian citizens in theoretical physics.
2006-2010 Training University Lecturers (FPU) studentship (2 years) and contract (2 years)from the Spanish government for the accomplishment of my PhD courses and thesis.
2005 Studentship from the Spanish Government for the collaboration with the Departa-ment d’Estructura i Constituent de la Matèria at the University of Barcelona.This collaboration was developed within the framework of the research project enti-tled: Static and Dynamic Properties of Correlated Bosonic and Fermionic Systems.
2000-2004 Studentship from the Spanish government (providing full support for the Universitytuition).
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 4/17
Computer skillsAdvanced OS: Linux, WindowsAdvanced Fortran77
LanguagesSpanish NativeCatalan NativeEnglish Fluent spoken and writtenItalian Fluent spoken and written
Bibliometric indicators of my publications2008 First publication academic age < 6 years
32 Total number of publications publications per year > 5{ In A-class journals: 20{ In conference proceedings: 11{ In book or chapter: 1Source: Thompson & Reuters AuthorID: E-4541-2013Source: Scopus (no data on 2013) AuthorID: 25641764000Source: Google Schoolar Citations
List of PublicationsP1 Impact of the symmetry energy on the outer crust of non-accreting neutron stars
Authors X.Roca-Maza and J.PiekarewiczJournal Phys. Rev. C 78 025807
Year 2008
P2 Nuclear symmetry energy probed by neutron skin thickness of nucleiAuthors M. Centelles, X. Roca-Maza, X. Viñas, M. WardaJournal Phys. Rev. Lett. 102 122502
Year 2009
P3 Neutron skin thickness in droplet model with surface width dependence: indicationsof softness of the nuclear symmetry energy
Authors M. Warda, X. Viñas, X. Roca-Maza, M. CentellesJournal Phys. Rev. C 80 024316
Year 2009
P4 Analysis of bulk and surface contributions in the neutron skin of nucleiAuthors M. Warda, X. Viñas, X. Roca-Maza, M. Centelles
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 5/17
Journal Phys. Rev. C 81 054309Year 2010
P5 Origin of the neutron skin thickness of 208Pb in nuclear mean-field modelsAuthors M. Centelles, X. Roca-Maza, X. Viñas, M. WardaJournal Phys. Rev. C 82 054314
Year 2010
P6 Theoretical study of elastic electron scattering off stable and exotic nucleiAuthors X.Roca-Maza,M. Centelles, F. Salvat, X, ViñasJournal Phys. Rev. C 78 044332
Year 2008
P7 Neutron skin of 208Pb, nuclear symmetry energy, and the parity radius experimentAuthors X. Roca-Maza, M. Centelles, X. Viñas, M. WardaJournal Phys. Rev. Lett. 106 252501
Year 2011
P8 Relativistic mean field interaction with density dependent meson-nucleon verticesbased on microscopical calculations
Authors X. Roca-Maza, X. Viñas, M. Centelles, P. Ring and P. SchuckJournal Phys. Rev. C 84 054309
Year 2011
P9 Influence of the symmetry energy on the giant monopole resonance of neutron-richnuclei
Authors M. Centelles, S.K. Patra, X. Roca-Maza, B.K. Sharma, P.D. Stevenson, X. ViñasJournal J. Phys. G 37 075107
Year 2010
P10 Garvey-Kelson Relations for Nuclear Charge RadiiAuthors J. Piekarewicz, M. Centelles, X. Roca-Maza, X. ViñasJournal Eur. Phys. J. A 46 379-386
Year 2010
P11 Low-lying dipole response: isospin character and collectivity in 68Ni, 132Sn and208Pb
Authors X. Roca-Maza, G. Pozzi, M. Brenna, K. Mizuyama and G. ColòJournal Phys. Rev. C 85 024601
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 6/17
Year 2012
P12 Electric dipole polarizability and the neutron skinAuthors J. Piekarewicz, B. K. Agrawal, G. Colò, W. Nazarewicz, N. Paar, P.-G. Reinhard, X.
Roca-Maza and D. VretenarJournal Phys. Rev. C 85 041302(R)
Year 2012
P13 Second-order equation of state with the full Skyrme interaction: toward new effec-tive interactions for beyond-mean-field models
Authors K. Moghrabi, M. Grasso, X. Roca-Maza and G. ColòJournal Phys. Rev. C 85 044323
Year 2012
P14 Constraints on the symmetry energy and neutron skins from experiments and theoryAuthors M. B. Tsang, J. R. Stone, F. Camera, P. Danielewicz, S. Gandolfi, K. Hebeler, C. J.
Horowitz, Jenny Lee, W. G. Lynch, Z. Kohley, R. Lemmon, P. Möller, T. Murakami,S. Riordan, X. Roca-Maza, F. Sammarruca, A. W. Steiner, I. Vidaña, and S. J.Yennello
Journal Phys. Rev. C 86 015803Year 2012
P15 A new Skyrme interaction with improved spin-isospin propertiesAuthors X.Roca-Maza, G. Colò and H. SagawaJournal Phys. Rev. C 86 031306(R)
Year 2012
P16 Localized form of Fock terms in nuclear covariant density functional theoryAuthors Haozhao Liang, Pengwei Zhao, Peter Ring, Xavier Roca-Maza, and Jie MengJournal Phys. Rev. C 86 021302(R)
Year 2012
P17 Electron scattering in isotonic chains as a probe of the proton shell structure ofunstable nuclei
Authors X. Roca-Maza, M. Centelles, F. Salvat, X. ViñasJournal Phys. Rev. C 87 014304
Year 2013
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 7/17
P18 Giant Quadrupole Resonances in 208Pb, the nuclear symmetry energy and the neu-tron skin thickness
Authors X. Roca-Maza, M. Brenna, B. K. Agrawal, P. F. Bortignon, G. Colò, Li-Gang Cao,N. Paar, and D. Vretenar
Journal Phys. Rev. C 87 034301Year 2013
P19 Electric Dipole Polarizability in 208Pb: correlations suggested by the Droplet ModelAuthors X. Roca-Maza, M. Brenna, G. Colò, M. Centelles, X. Viñas, B. K. Agrawal, N. Paar,
J. Piekarewicz, and D. VretenarJournal Phys. Rev. C 88 024316
Year 2013
P20 Constraints on the symmetry energy near normal density from atomic masses andneutron skins in heavy nuclei
Authors X. Viñas, M. Centelles, X. Roca-Maza and M. WardaJournal Eur. Phys. J. A 50 27
Year 2014
P21 Influence of the single-particle structure on the nuclear surface and the neutron skinAuthors M. Warda, M. Centelles, X. Viñas, and X. Roca-MazaJournal In preparation
Year 2013
P22 Information content of the weak-charge form factorAuthors P.-G. Reinhard, J. Piekarewicz, W. Nazarewicz, B.K. Agrawal, N. Paar, X. Roca-
MazaJournal Phys. Rev. C 88 034325
Year 2013
Conference Proceedings & Volume ContributionsC1 The Impact of the Nuclear Symmetry Energy on the Structure and Composition of
the Outer CrustAuthors X. Roca-Maza, T. Garía, M. Centelles and J. PiekarewiczChapter “Neutron Star Crust”. Nova Publishers. ISBN: 978-1-62081-960-9.
Year 2012
C2 Study of the neutron skin thickness of 208Pb in mean field models
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
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Authors X. Roca-Maza, M. Centelles, X. Viñas, M. WardaJournal J. Phys. : Conf. Ser. 321 012052
Year 2011
C3 Nuclear symmetry energy and neutron skin thicknessAuthors M. Warda, M. Centelles, X. Viñas and X. Roca-MazaJournal A. Phys. Pol. B 43 209
Year 2012
C4 Neutron skin thickness in neutron rich nuclei: bulk and surface contributions andshell effects
Authors X. Viñas, M. Warda, M. Centelles and X. Roca-MazaJournal Int. J. Mod. Phys. E 21 12500292
Year 2012
C5 Density dependence of the symmetry energy from neutron skin thickness in finitenuclei
Authors X. Viñas, M. Centelles, X. Roca-Maza, and M. WardaJournal AIP Conf. Proc. 1491 101
Year 2012
C6 The pygmy dipole strength, the neutron radius of 208Pb and the symmetry energyAuthors X. Roca-Maza, M. Brenna, M. Centelles, G. Colò, K. Mizuyama, G. Pozzi, X. Viñas
and M. WardaJournal J. Phys. : Conf. Ser. 342 012009
Year 2012
C7 Sensitivity of the electric dipole polarizability to the neutron skin thickness in 208PbAuthors X. Roca-Maza, B. K. Agrawal, G. Colò, W. Nazarewicz, N. Paar, J. Piekarewicz,
P.-G. Reinhard, D. VretenarJournal AIP Conf. Proc. 1491 204
Year 2012
C8 Local covariant density functional constrained by the relativistic Hartree-Fock the-ory
Authors H. Z. Liang, J. Meng, P. Ring, X. Roca-Maza, P. W. ZhaoJournal AIP Conf. Proc. 1491 230
Year 2012
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 9/17
C9 New Skyrme energy density functional for a better description of the Gamow-TellerResonance
Authors X.Roca-Maza, G. Colò and H. SagawaJournal Phys. Scr. T154 014011
Year 2013
C10 Low-lying dipole response in stable and exotic nucleiAuthors M. Brenna, X. Roca-Maza, G. Colò, P. F. Bortignon, K. Mizuyama, and G. PozziJournal Phys. Scr. T154 014020
Year 2013
C11 Microscopic calculations beyond mean-field with zero-range effective interactionsAuthors M. Brenna, G. Colò, P. F. Bortignon and X. Roca-MazaJournal EPJ Web of Conferences 38 04005
Year 2013C12 A beyond-mean-field example with zero-range effective interactions in infinite nu-
clear matterAuthors K. Moghrabi, M. Grasso, X. Roca-Maza, G. Colò, and N. Van GiaiJournal EPJ Web of Conferences 38 06002
Year 2013C13 Nuclear Symmetry Energy: constraints from Giant Quadrupole Resonances and
Parity Violating Electron ScatteringAuthors X. Roca-Maza, B. K. Agrawal, P. F. Bortignon, M. Brenna, M. Centelles, G. Colò,
Li-Gang Cao, N. Paar, X. Viñas, D. Vretenar, and M. WardaJournal EPJ Web of Conferences 66 02092
Year 2014C14 Nuclear charge-exchange excitations in localized covariant density functional theory
Authors H. Z. Liang, J. Meng, T. Nakatsukasa, Z. M. Niu, P. Ring, X. Roca-Maza, N. VanGiai and P. W. Zhao
Journal EPJ Web of Conferences 66 02064Year 2014C15 A microscopic model beyond mean-field: from giant resonances properties to the
fit of new effective interactionsAuthors M. Brenna, G. Colò, X. Roca-Maza, P. F. Bortignon, K. Moghrabi and M. GrassoJournal EPJ Web of Conferences 66 02015
Year 2014
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 10/17
Conference Talks & SeminarsTitle Unraveling the dependence of the Electric Dipole Polarizability on the isovector
properties of the nuclear effective interactionConference Invited seminar
Place University of Barcelona, 19 SeptemberYear 2013
Title The Nuclear Symmetry Energy: Constraints from Giant ResonancesConference Invited talk at the 3rd International Symposium on Nuclear Symmetry Energy.
Place NSCL/FRIB, East Lansing (USA) 22-26 July.Year 2013
Title Unraveling the dependence of the Electric Dipole Polarizability on the isovectorproperties of the nuclear effective interaction
Conference Invited talk at the first International Collaboration in Nuclear Theory (ICNT) topicalprogram on "Symmetry Energy in the Context of New Radioactive Beam Facilitiesand Astrophysics".
Place NSCL/FRIB, East Lansing (USA) 15 July - 9 August.Year 2013
Title The nuclear symmetry energy: constraints from giant resonances and parity violat-ing electron scattering
Conference Talk at the International Nuclear Physics Conference 2013Place Firenze (Italy) 2-7 June.Year 2013
Title The Nuclear Symmetry Energy: constraints from Giant ResonancesConference Invited Seminar at the Physics Department of Surrey University
Place Guildford (UK) 14 May.Year 2013
Title Elastic electron scattering as a revitalized experimental tool in modern nuclearphysics: a theoretical point of view.
Conference Internal Seminar of the Nuclear Physics SectionPlace Milano (Italy) 8 May.Year 2013
Title Local covariant density functional constrained by the relativistic Hartree-Fock the-ory.
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 11/17
Conference Internal Seminar of the Nuclear Physics SectionPlace Milano (Italy) 6 May.Year 2013
Title Parity Violating Asymmetry, Dipole Polarizability, and the Neutron Skin Thickness.Conference Invited talk at the Calcium Radius Experiment (CREX) Workshop at Jefferson Lab
Place Newport News (USA) 17-19 March.Year 2013
Title Electron scattering as a probe of surface properties and proton shell structure ofunstable nuclei.
Conference Invited RIBF Nuclear Physics Seminar at RIKEN Nishina Center.Place Wako (Japan) 8 March.Year 2013
Title The Nuclear Symmetry Energy: constraints from Giant Resonances.Conference Talk at the “Trobades de Nadal”.
Place Barcelona (Spain) 19-20 December.Year 2012
Title New Skyrme energy density functional for a better description of charge-exchangeresonances.
Conference Invited talk at the 19th Nuclear Physics Workshop - Marie & Pierre Curie.Place Kazimierz (Poland) 26-30 September.Year 2012
Title Dipole Polarizability and Parity Violating Asymmetry in 208Pb.Conference Invited key note talk at the 2nd European Nuclear Physics Conference - EuPNC
2012.Place Bucharest (Romania) 16-21 September.Year 2012
Title Dipole Polarizability and Parity Violating Asymmetry in 208Pb.Conference Talk at the conference Nuclear Dynamics and Structure II.
Place Opatija (Croatia) 9-13 July.Year 2012
Title Dipole Polarizability and Parity Violating Asymmetry in 208Pb.
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 12/17
Conference Invited talk at the workshop The Nuclear Dipole Polarizability and its Impact onNuclear Structure and Astrophysics.
Place Trento (Italy) 18-22 June.Year 2012
Title Pygmy dipole resonances in stable and unstable nuclei.Conference Talk at the 1st Topical Workshop on Modern Aspects in Nuclear Structure.
Place Bormio (Italy) 22-25 February.Year 2012
Title The pygmy dipole strength, the neutron radius of 208Pb and the symmetry energy.Conference Talk at the II Iberian nuclear astrophysics meeting.
Place Salamanca (Spain), 22-23 September.Year 2011
Title Relativistic mean field interaction with density dependent meson-nucleon verticesbased on microscopical calculations
Seminar University of Coimbra. Physics Department.Place Coimbra (Portugal), 20 September 2011.Year 2011
Title The Dipole Strength: Microscopic Properties and Correlations with the SymmetryEnergy and the Neutron Skin Thickness
Conference Invited talk at the International Symposium on Nuclear Symmetry Energy.Place Northampton (MA), 17-20 June.Year 2011
Title Density dependence of the nuclear symmetry energy estimated from neutron skinthickness in finite nuclei.
Conference Talk at the JAPAN-ITALY EFES Workshop.Place Turin (Italy), 6-8 September.Year 2010
Title Density dependence of the nuclear symmetry energy estimated from neutron skinthickness in finite nuclei.
Seminar University of Milan. Physics Department.Place Milan (Italy), 3 November.Year 2010
Via Pacini 26 – Milano, Italy 20131H (+39) 338 117 00 94 • T (+39) 02 503 17 290
B [email protected] • Í www.mi.infn.it/ jroca/ 13/17
Title The Smoothness of Physical ObservablesSeminar University of Barcelona. Physics Department.
Place Barcelona (Spain), 29 May.Year 2009
Brief Professional BiographyResearch Activities
I started my research activity in 2005 together with my DEA studies. Currently and during my PhDI focused on different aspects in Nuclear Physics. One of the main topics is the nuclear symmetryenergy and its connection to ground state and excited state properties of finite nuclei. The nuclearsymmetry energy is a basic property of the nuclear Equation of State, it represents the energy costper particle to convert all protons into neutrons in symmetric nuclear matter, and still lacks of anaccurate characterization. It impacts on a variety of physical systems, from the very big: the sizeof a neutron star or its composition and structure [P1,C1]; to the very small: the neutron skinthickness of a heavy nucleus [P2,P3,P4,P5,P14,P20,P21,C2,C3,C4,C5].
I have also devoted part of my research to the theoretical study of elastic electron scattering bystable and exotic nuclei [P6,P17]. This is mainly motivated by the advent of new Rare Ion BeamFacilites around the world that host projects (like ELIse at GSI, Germany, or SCRIT at RIKEN,Japan) aimed at measuring elastic electron cross sections in exotic nuclei.
The gained experience has allowed us to connect our previous knowledge on the symmetry energy,the neutron skin thickness in nuclei and the elastic electron scattering by nuclei to study the NuclearMean Field predictions for the measured Parity Violating Asymmetry in 208Pb at the JeffersonLaboratory (USA) [P5,P7,C6].
In parallel to all these investigations, I have always been concerned about the connection betweenab initio calulations of infinite nuclear matter based on empirical nucleon-nucleon potentials (such asBrueckner-Hartee-Fock or Dirac-Brueckner-Hartee-Fock calculations) and finite nuclei. Nowadays,medium-heavy and heavy mass nuclei can only be extensively calculated by using Effective MeanField techniques and the predictions of this approach for infinite nuclear matter are not always ingood agreement with available ab initio calculations. As a first attempt to build a bridge betweenab initio and effective mean field theories, we have developed a relativistic mean field model withdensity dependent meson-nucleon vertices based on state-of-the-art ab initio results [P8].
We have also analyzed theoretically the effects of the symmetry energy on the Giant MonopoleResonance —a nuclear excitation of atomic nuclei— in neutron-rich nuclei [P9]; and a systematicstudy of nuclear charge radii along the whole periodic table by taking advantage of the Garvey andKelson Relations extended for such an investigation[P10].
In 2010, at the Sezione di Milano of the INFN, my research took a different direction. Althoughmany times related with my previous experience, I started the study of nuclear excitations withinthe Random Phase Aproximation (RPA) and the Particle Vibration Coupling approach. In partmotivated by my previous experience on the symmetry eneregy and in part motivated by the factthat such a property may be related to a new exotic mode that appear in neutron-rich nuclei, namelyPygmy Dipole Resonance (the group in Milano has predicted such a relation but it is still underdebate), we started a detailed investigation of such an exotic mode in different nuclei and by means
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of different Skyrme mean field interactions [P11,C6,C10]. Moreover, we are currently trying toconfirm or disproof the correlation between the Pygmy Dipole Resonance and the symmetry energyby means of a more rigorous statistical analysis (covariance analysis of some selected mean-fieldmodels) as well as the model correlation between the dipole polarizability and the neutron skinthickness of medium and heavy nuclei [P12,P19,C7]. We argue in [P12,C7] that experiments on thedipole polarizability can complement PREx-like experiments and allow us to better constraint thedensity dependence of the symmetry energy at saturation. In addition, we show in [P19] that thedipole polarizability in heavy mass nuclei times the symmetry energy at saturation correlates withthe neutron skin thickness and also with the slope of the symmetry energy at saturation. Hence,further encouraging measrements on such an observable.
At the same time, I had the opportunity to learn about the Particle Vibration Coupling approach andhelp in the supervision of the Master thesis of Giacomo Pozzi (see teaching activity). In this thesis,G. Pozzi developed an original model for the calculation of the dipole response of 67,69Ni motivatedby the need of understanding the measurements on those nuclei performed by the experimentalgroup at Milano.
Parallel to that, we started also new collaborations. The first one is with the Orsay group with whichwe try to develope a Skyrme-like Beyond Mean Field approach (first order in perturbation theorybeyond the mean field) for the calculation of infinite nuclear matter [P13,C12] and eventually finitenuclei [C11] —currently under development. In a second project, in collaboration between Milanoand Aizu, we built a new Skyrme interaction (SAMi) which overcomes some drawbacks of existingmean field models such as the inaccurate description of spin-isospin properties in nuclei [P15,C9].In the near future, we also plan to include the tensor channel in the SAMi effective interactionin order to further improve the accuracy in the description of charge-exchange resonances. In athird project, I had also the oportunity to collaborate with the Beijing group in developing a newtechniche for expressing Fock terms in a local from [P16,C8]. This work may provide importantimplications on both the building of new effective interactions and the developement of beyondmean-field calculations where the effect of exchange terms should be included. On this regard, ourfirst step is developing a point coupling relativistic effective interaction based on a similar fittingprocedure than in [P8] but in this case including the Fierz transformations in order to account forthe effect of the exchange (or Fock) terms.
On the other side, the use of a new experimental technique in combination with a monocromatic andpolarized high energy γ−ray source available at Duke University has allowed to improve the accuracyon the determination of the Isovector Giant Quadrupole Resonance. This fact has motivated ourtheoretical investigation on such a collective nuclear mode on the bases of different microscopicmodels. Specifically, we have anayzed the connection of the excitation energy of the IVGQR[P18,C13] and of the quadrupole polarizability [C13] with the isospin properties of the nucleareffective interaction.
Following our studies on the neutron skin thickness, we have recently analyzed the effects of thesingle-particle properties on its formation and, in general, on the nuclear surface. For this purpose,we have analyzed the predictions of different mean-field models along some selected isotopic chains[P21].
As previously mentioned, the symmetry energy is one of the common threads in my theoreticalinvestigations and the experience gained on this topic as well as the different collaborations settledalong my scientifical carrear have allowed me to participate in a summary paper writen as an
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outcome of the NuSYM symposium celebrated in 2011 in the Smith College, Northampton (USA)[P14] and also to be invited together with X. Viñas and M. Centelles from Barcelona Universityand M. Warda from Lublin University to write a review paper on a special volume on the nuclearsymmetry energy to be published by the European Physical Journal A [P20].
Future Perspectives
Many attempts have been made to give an approximate solution to the nuclear many body problemin the past and this effort continues also in the present. One of the most successful and commonlyused approaches to describe the nucleus is based on effective interactions, either in the relativistic orin the non-relativistic frameworks as pointed out earlier. Effective interactions have been traditionallyimplemented at the mean-field level where an independent particle picture is adopted. Such anapproach provides a rather accurate description of the bulk properties of nuclei and, generally, lessaccurate predictions for detailed spectroscopic properties, excitations and reaction processes in nuclei.For this reason, we are in the first stages of development of a new approach beyond the mean-fieldfor the calculation of finite nuclei: (i) as a first test, the first order correction to the mean-fieldenergy will be included; (ii) more realistically, instead, the interaction between the nucleonic and thevibrational degrees of freedom will be then studied at the same level of approximation. In both cases,the parameters of the effective interaction will be refitted to reproduce some selected empirical data.Such a strategy aims to provide a unified description not only of the bulk properties of nuclei butalso of the nuclear excitations.
In close connection, we also plan to study the low-lying dipole strength in odd nuclei by usingthe particle-vibration coupling approach and a study of spin-isospin resonances in exotic nucleiusing a non-relativistic SAMi-like interaction with tensor terms in the Hamiltonian with the aimof understanding and further overcoming some drawbacks of existing effective interactions in thedescription of spin-isospin properties in nuclei.
As briefly highlighted, we also plan to build a point coupling relativistic effective interaction where theeffective Lagrangian contains all possible channels allowed by the symmetries, that is, scalar, vector,pseudo-scalar, pseudo-vector and tensor terms all in both the isoscalar and isovector channels. Onlyfour of these channels will be fitted to experimental data and the rest will be fixed self-consistentlyduring the Hartree-calculations via the Fierz transformations. In this way the parameter spaceis reduced, the predictive power of the approach is not compromised and the tecnical difficultiesinherent in Fock terms are avoided keeping its effects in an effective but efficient way.
The recent experimental determination of the analyzing power in polarized electron scattering off208Pb by the PREx collaboration at the Jefferson Laboratory have settled a new puzzle for nucleartheoriticians. The analyzing power, or transverse asymmetry, is zero at the first Born approximationand non-zero in the experiment. Actually, it has been shown to be dominated by two photonexchange contributions in light nuclei. However, the same type of calculations fail dramaticallyfor the case of 208Pb. We plan to include to the effect of Coulomb distortions –thought to beimportant in heavy mass nuclei– in the calculations of this observable assuming an imaginary partin the optical potential that is though to simulate the effect of two (or more) photon exchange.
Related with the measurement of the analyzing power in polarized electron scattering, we are startinga collaboration with the experimental group at the Jefferson Laboratory responsible of the Mottpolarimeter with the aim of improving its performance. This will impact on many experimentsplaned before and after the upgrade of this important facility for the study of the fundamental
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interactions.
Finally, the Self-Confining Rare Isotope Target (SCRIT) facility is planed to become completelyoperative the next year and will become a world-unique experimental tool for the study of fundamentalproperties in exotic nuclei. The first measurements will determine the unknown electromagneticdistribution of unstable Sn (Z=50) isotopes via elastic electron scattering. The initial target willbe 132Sn predicted to be a doubly magic nucleus with spherical shape by succesful nuclear models.Although not planned yet, the measurement of the dipole response in exotic nuclei might be feasibleusing the SCRIT facility via the experimental study of inelastically scattered electrons at forwardangles. Motivated by this exciting experimental developements, we plan to investigate the influenceof the experimental determination of the electromagnetic charge radius and the electric dipolepolarizability in an exotic nucleus such as 132Sn on the characterization of the isovector properties ofthe nuclear effective interaction. If succesful, the measurement of this two observables employing thesame facility and for different isotopes will be strongly encouraged since systematic measurementswill reduce the experimental uncertainties on the studied quantities and, hopefully, on the propertiesof the symmetry energy around saturation density.
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