## Current professional information

Present Status: Postdoctoral researcher
Grant: H2020 Marie Sklodowska-Curie
Juan de la Cierva-Incorporación
Length: Since September 2017

Institution: Institut de Física d'Altes Energies (IFAE)
Universitat Autònoma Barcelona (UAB)
Address: Edifici Cn, Universitat Autònoma de Barcelona
E-08193 Bellaterra (Barcelona), España
Phone: +34 935 814284
Fax: +34-935-814337
E-mail: jsegovia@ifae.es
jorge.segonza@gmail.com

ResearcherID: C-7202-2015
ORCID-ID: 0000-0001-5838-7103

Specialization (UNESCO codes):
Elementary Particles (221202)
Quantum Field Theory (221212)

I am currently a Marie Sklodowska-Curie and Juan de la Cierva postdoctoral researcher at the Institut de Física d'Altes Energies (IFAE) of the Universidad Autònoma de Barcelona (Barcelona, Spain). Since my starting date in September 2017, I am studying with A. Pineda the physics of heavy quarks using the effective field theory approach. An example is the high precision determination of standard model parameters such as quark masses using nonrelativistic effective field theories, but another one is the development of novel effective field theories to systematically study the so-called XYZ mesons. There is growing evidence that these particles are new forms of matter such as quark-gluon hybrids, mesonic molecules and tetraquarks. Our primary focus is on the hybrid candidates which are supposed to be the only bound states in Quantum Chromodynamics (QCD) which explicitly manifest gluonic degrees of freedom. Note that this research line is the continuation of my work done with N. Brambilla when I was an Alexander von Humboldt postdoctoral fellow within her group at the Physik-Department of the Technische Universität München (Munich, Germany). Besides my research duties at IFAE, I am actively involved in the very vibrant academic life of Universidad Autònoma de Barcelona, for instance: I am teaching theory lectures of Physics in the Mathematics degree, I am tutoring undergraduate and master students and I am participating in the IFAE's mentoring program.

## News

### Aug 20-23, 2017

The 11th International Workshop on the Physics of Excited Nucleons Nstar 2017 will be held at the University of South Carolina, Columbia, SC

Synergistic efforts between experimentalists and theorists have already demonstrated our capability to address some open key problems of hadron physics on the nature of hadron mass, quark-gluon confinement, and their emergence from QCD via the exploration of the baryon structure and spectrum including the search for the new states of hadron matter such as hybrid and 'multi-quark' baryons. The purpose of this workshop is to share the latest results on various aspects of low-energy QCD dynamics in terms of N* resonances, and to discuss the future developments.

### May 28 - Jun 3, 2017

The FAIRness 2017 is the fifth edition in a series of workshops designed to bring together excellent international young scientists with research interests focused on physics at FAIR.

The topics of the workshop cover a wide range of aspects in both theoretical developments and current experimental status, concentrated around the four scientific pillars of FAIR. There will be an inspiring mixture of new theoretical developments and experimental research: Atomic and plasma physics; biophysics; material sciences and applications; Nuclear structure, astrophysics and reactions; Physics of hot and dense nuclear matter; QCD phase transitions and critical point; Hadron Spectroscopy, Hadron Structure, Hadrons in matter and Hypernuclei; Experimental programs APPA, CBM, HADES, NUSTAR, PANDA, as well as BES, NICA and the RHIC beam energy scan.

### Dec 5-8, 2016

The Science Week 2016 of the Excellence Cluster Universe will be held in Munich, Germany

For the 10th time, the Cluster hosts its annual 'Science Week'. From 5 to 8 December 2016 Cluster scientists and invited guests will present their current research work in the fields of astrophysics, cosmology, particle and nuclear physics. The Science Week is an interdisciplinary event and directed to all scientists who want to gain insight into the current state of all Cluster research areas A-I. Everybody is welcome.

### Oct 17-21, 2016

The 3rd edition of the Nonperturbative QCD series will be held in Seville, Spain

This will be a meeting on Nonperturbative aspects of QCD and Hadro-Particle Physics (locally) organized by the Nuclear and Particle Physics research group at the Universities of Huelva (UHU), Hispalense (USE) and Pablo de Olavide (UPO) in Seville, Spain. This meeting aims to bring together experts in Nuclear, Hadron and Particle Physics in order to facilitate the communication, and discern and highlight those features of their common foundation which should provide a means of bridging the gap between the fundamental interactions between elementary particles and an explanation of nuclear forces.

### Aug 28 - Sep 3, 2016

XII Quark Confinement and the hadron spectrum (Confinement12) will be held in Thessaloniki, Greece.

Inaugurated in 1994 in Como, Italy, this series of conferences has become an important forum for scientists working on strong interactions, stimulating exchanges among theorists and experimentalists as well as across related fields. The twelfth edition of this conference series will take place in Thessaloniki (Greece) from 29th August to 3rd September 2016 in Makedonia Palace conference centre. Thessaloniki, founded more than 2500 years ago in the north Greece, overlooking the gulf of Thermaikos, has always been a meeting point for people of different cultures. Today, a modern city with marks of the past, is an inspiring place welcoming international events and conferences.

### May 16-20, 2016

The international conference Baryons 2016 will be held at Florida State University in Tallahassee, Florida, USA.

The BARYONS series of international conferences started in 1970 at Duke University, and since then it has been held roughly every three years in important cities around the world. Following the successful conferences in Osaka, Japan in 2010 and Glasgow, Scotland in 2013, the next in the series will be held in 2016 in Tallahassee, Florida. The conference will highlight the physics of baryons and related subjects in particle, nuclear, and astrophysics. The main issues to be discussed are our understanding of the structure and reactions of baryons from the fundamental theory of the strong interaction, Quantum Chromodynamics (QCD). In particular, the highly non-perturbative phenomena of quark confinement, mass generation, and spontaneous breaking of chiral symmetry will be addressed. Recent developments of new and forthcoming facilities in the world will also be showcased. We strongly encourage the participation of young scientists, including students and postdocs.

### March 8, 2016

The web page of the Seccion Exterior of the Real Sociedad Española de Fisica has been launched. You can visit it here

### October 12-16, 2015

The workshop Nucleon Resonances: From Photoproduction to High Photon Virtualities will be held at ECT* (Trento)

The workshop will be devoted to the study of the nucleon resonance spectrum and structure as it becomes accessible through the electromagnetic excitation of the nucleon (EmNN*) in exclusive meson production. It will focus on: (a) the baryon spectrum in exclusive meson photoproduction, (b) the search for new baryon states in combined studies of exclusive photo- and electroproduction, (c) electroexcited N* states and their structure at photon virtualities up to 5 GeV2, and (d) the extension of these studies in the near future up to 12 GeV2. This will give us the unique opportunity to establish the baryon spectrum from experimental photoproduction data under minimal model dependence as well as to explore the complex interplay of quark-gluon and meson-baryon degrees of freedom in the N* structure and the transition from quark-gluon confinement towards perturbative QCD as it is revealed in the structure of excited nucleons with different quantum numbers. The workshop will focus particularly on new results from ELSA, JLab, and MAMI and the development of future strategies, methods, and approaches to extract, predict, and understand the baryon spectrum and its EmNN* photo- and electrocouplings based on QCD. It will thus address key problems of contemporary hadron physics: dynamical generation of hadron mass by strong interaction in the non-perturbative regime, dynamical breaking of the QCD Lagrangian symmetries, and the nature of quark-gluon confinement in light baryons. The workshop aims to strengthen already existing, and to initiate new, international collaborations, particularly with EU research institutions and universities, and to create opportunities to facilitate and stimulate further discussions and growth in this field.

### September 21-25, 2015

The workshop Light-Cone 2015 will be held at INFN Frascati National Laboratories

LC2015 belongs to a conference series that started in 1991 under the supervision of the International Light Cone Advisory Committee and showed, year by year, to play a vital role in promoting the research towards a rigorous description of hadrons and nuclei, based on Light-Cone quantization methods. A strong relation with the experimental activity represents an important commitment of the Light-Cone community, with the ambition "to assist in the development of crucial experimental tests at hadron facilities". To emphasize this goal, the LC2015 venue will be the INFN National Laboratories in Frascati. In anticipation of opportunities afforded by new facilities, such as the 12 GeV upgrade of Th. Jefferson Natl. Lab, the FAIR facility at GSI, J-PARC, and other facilities around the globe, we aim to have a scientific program that could have a stimulating impact on the forefront research development of nuclear, hadron and particle physics. In particular, LC2015 will address the following topics: 1) Hadron Physics in present and future facilities, 2) Nonperturbative methods in quantum field theory, 3) AdS/CFT - Theory and applications, 4) Light-front field theory in QCD and QED, 5) Few-body problems on the Light Cone, 6) Lattice Gauge Theories, and 7) Relativistic models of nuclear and hadronic structures.

### June 15-17, 2015

The Spanish Hadron Excellence Network celebrates its first meeting at IFIC (Valencia)

The groups included in the Hadron Spanish Excellence Network are deeply involved in the development of some of the Hadronic Physics most advanced techniques, namely: Effective Field Theories, dispersive approaches, lattice QCD, Regge Theory, or finite density and temperature formalisms. Still, not all the groups master all these techniques, whereas progress in the field requires the combination of different formalisms to keep up with the level of excellence. Hence, the purpose of this network is to facilitate the communication and foster the collaboration within different Spanish Hadron Physics groups, while consolidating the existing research programs. For this purpose, the network provides financial support to the members of the groups to meet in order to establish or consolidate collaborations, to organize seminars to present to one group the techniques developed and used by other groups, as well as to organize workshops to introduce all techniques, where members of all groups may participate, particularly the youngest ones.

## Last publications

### Canonical description of the new LHCb resonances

Abstract. The LHCb Collaboration has recently observed four $J/\psi\phi$ structures called X(4140), X(4274), X(4500) and X(4700) in the B^{+}\to J/\psi\phi K^{+} decays. We study them herein using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components. The X(4140) resonance appears as a cusp in the J/\psi\phi channel due to the near coincidence of the D_{s}^{+-}D_{s}^{\ast+-} and J/\psi\phi mass thresholds. The remaining three X(4274), X(4500) and X(4700) appear as conventional charmonium states with quantum numbers 3^{3}P_{1}, 4^{3}P_{0} and 5^{3}P_{0}, respectively; and whose masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds. A particular feature of our quark model is a lattice-based screened linear confining interaction that has been constrained in the light quark sector and usually produces higher excited heavy-quark states with lower masses than standard quark model predictions.

### Dissecting nucleon transition electromagnetic form factors

Abstract. In Poincar\'e-covariant continuum treatments of the three valence-quark bound-state problem, the force behind dynamical chiral symmetry breaking also generates nonpointlike, interacting diquark correlations in the nucleon and its resonances. We detail the impact of these correlations on the electromagnetically-induced nucleon-$\Delta$ and nucleon-Roper transitions, providing a flavour-separation of the latter and associated predictions that can be tested at modern facilities.

### Molecular components in P-wave charmed-strange mesons

Abstract. Results obtained by various experiments show that the Ds0*(2317) and Ds1(2460) mesons are very narrow states located below the DK and D*K thresholds, respectively. This is markedly in contrast with the expectations of naive quark models and heavy quark symmetry. Motivated by a recent lattice study which addresses the mass shifts of the c\bar{s} ground states with quantum numbers J^P=0^+ (Ds0*(2317)) and J^P=1^+ (Ds1(2460)) due to their coupling with S-wave D^{(*)}K thresholds, we perform a similar analysis within a nonrelativistic constituent quark model in which quark-antiquark and meson-meson degrees of freedom are incorporated. The quark model has been applied to a wide range of hadronic observables and thus the model parameters are completely constrained...

### Understanding the nucleon as a Borromean bound-state

Abstract. Analyses of the three valence-quark bound-state problem in relativistic quantum field theory predict that the nucleon may be understood primarily as a Borromean bound-state, in which binding arises mainly from two separate effects. One originates in non-Abelian facets of QCD that are expressed in the strong running coupling and generate confined but strongly-correlated colour-antitriplet diquark clusters in both the scalar-isoscalar and pseudovector-isotriplet channels. That attraction is magnified by quark exchange associated with diquark breakup and reformation. Diquark clustering is driven by the same mechanism which dynamically breaks chiral symmetry in the Standard Model. It has numerous observable consequences, the complete elucidation of which requires a framework that also simultaneously expresses the running of the coupling and masses in the strong interaction. Planned experiments are capable of validating this picture.

### Completing the picture of the Roper resonance

Abstract. We employ a continuum approach to the three valence-quark bound-state problem in relativistic quantum field theory to predict a range of properties of the proton's radial excitation and thereby unify them with those of numerous other hadrons. Our analysis indicates that the nucleon's first radial excitation is the Roper resonance. It consists of a core of three dressed-quarks, which expresses its valence-quark content and whose charge radius is 80% larger than the proton analogue. That core is complemented by a meson cloud, which reduces the observed Roper mass by roughly 20%. The meson cloud materially affects long-wavelength characteristics of the Roper electro-production amplitudes but the quark core is revealed to probes with Q^2 > 3m^2 .

### Charmed-strange meson spectrum: Old and new problems

Abstract. The LHCb Collaboration has recently reported the observation for the first time of a spin-3 resonance in the heavy quark sector. They have shown that the D^0 K^- structure seen in the Bs^0 -> D^0 K^- pi^+ reaction and with invariant mass 2.86 GeV is an admixture of a spin-1 and a spin-3 resonances. Motivated by the good agreement between our theoretical predictions some time ago and the properties extracted from the experiment of the Ds1*(2860) and Ds3*(2860) states, we perform an extension of the study of the strong decay properties of the DsJ*(2860) and present the same analysis for the Ds1*(2700) and DsJ(3040) mesons. This provides a unified and simultaneous description of the three higher excited charmed-strange resonances observed until now. For completeness, we present theoretical results for masses and strong decays of the low-lying charmed-strange mesons and those experimental missing states which belong to the spin-multiplets of the discovered Ds1*(2700), DsJ*(2860) and DsJ(3040) resonances. The theoretical framework used is a constituent quark model which successfully describes hadron phenomenology from light to heavy quark sectors.

## Lectures

• Physics for Mathematicians. I am teaching theory lectures of the subject Physics to be delivered in the Bachelor of Mathematics at Universitat Autonòma de Barcelona. One can find the corresponding material of the subject here

• Quantum Mechanics. I have been involved on the development of the exercise lectures associated with this subject under the supervision of Prof. Dr. Nora Brambilla. One can find the corresponding material of the subject here

• Quantum Field Theory 2. I have taught the exercise lectures associated with this subject under the supervision of Prof. Dr. Nora Brambilla. One can find the corresponding material of the subject here

• Physics Applied to Biology. I have been instructor of the Laboratory courses associated with this subject under the supervision of Prof. Dr. Begoña Quintana. One can find the corresponding material of the subject here