Records |
Author |
Richard, J.M.; Valcarce, A.; Vijande, J. |
Title |
Stable heavy pentaquarks in constituent models |
Type |
Journal Article |
Year |
2017 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
Volume |
774 |
Issue |
|
Pages |
710-714 |
Keywords |
|
Abstract |
It is shown that standard constituent quark models produce ((c)over-barcqqq) hidden-charm pentaquarks, where c denotes the charmed quark and q a light quark, which lie below the lowest threshold for spontaneous dissociation and thus are stable in the limit where the internal (c)over-barc annihilation is neglected. The binding is a cooperative effect of the chromoelectric and chromomagnetic components of the interaction, and it disappears in the static limit with a pure chromoelectric potential. Their wave function contains color sextet and color octet configurations for the subsystems and can hardly be reduced to a molecular state made of two interacting hadrons. These pentaquark states could be searched for in the experiments having discovered or confirmed the hidden-charm meson and baryon resonances. |
Address |
[Richard, J. -M.] Univ Lyon, Inst Phys Nucl Lyon, IN2P3, CNRS UCBL, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France, Email: j-m.richard@ipnl.in2p3.fr; |
Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
|
Edition |
|
ISSN |
0370-2693 |
ISBN |
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Medium |
|
Area |
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Expedition |
|
Conference |
|
Notes |
WOS:000414973200093 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
3408 |
Permanent link to this record |
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Author |
Richard, J.M.; Valcarce, A.; Vijande, J. |
Title |
Few-body quark dynamics for doubly heavy baryons and tetraquarks |
Type |
Journal Article |
Year |
2018 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
Volume |
97 |
Issue |
3 |
Pages |
035211 - 10pp |
Keywords |
|
Abstract |
We discuss the adequate treatment of the three- and four-body dynamics for the quark model picture of double-charm baryons and tetraquarks. We stress that the variational and Born-Oppenheimer approximations give energies very close to the exact ones, while the diquark approximation might be somewhat misleading. The Hall-Post inequalities also provide very useful lower bounds that exclude the possibility of stable tetraquarks for some mass ratios and some color wave functions. |
Address |
[Richard, Jean-Marc] Univ Lyon, Inst Phys Nucl Lyon, CNRS UCBL IN2P3, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France, Email: j-m.richard@ipnl.in2p3.fr; |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2469-9985 |
ISBN |
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Medium |
|
Area |
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Expedition |
|
Conference |
|
Notes |
WOS:000428505400005 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
3543 |
Permanent link to this record |
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Author |
Quintero-Quintero, A.; Patiño-Camargo, G.; Soriano, A.; Palma, J.D.; Vilar-Palop, J.; Pujades, M.C.; Llorca-Domaica, N.; Ballester, F.; Vijande, J.; Candela-Juan, C. |
Title |
Calibration of a thermoluminescent dosimeter worn over lead aprons in fluoroscopy guided procedures |
Type |
Journal Article |
Year |
2018 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
Volume |
38 |
Issue |
2 |
Pages |
549-563 |
Keywords |
backscatter correction factor; TLD; lead apron; fluoroscopy; eye lens dose |
Abstract |
Fluoroscopy guided interventional procedures provide remarkable benefits to patients. However, medical staff working near the scattered radiation field may be exposed to high cumulative equivalent doses, thus requiring shielding devices such as lead aprons and thyroid collars. In this situation, it remains an acceptable practice to derive equivalent doses to the eye lenses or other unprotected soft tissues with a dosimeter placed above these protective devices. Nevertheless, the radiation backscattered by the lead shield differs from that generated during dosimeter calibration with a water phantom. In this study, a passive personal thermoluminescent dosimeter (TLD) was modelled by means of the Monte Carlo (MC) code Penelope. The results obtained were validated against measurements performed in reference conditions in a secondary standard dosimetry laboratory. Next, the MC model was used to evaluate the backscatter correction factor needed for the case where the dosimeter is worn over a lead shield to estimate the personal equivalent dose H-p(0.07) to unprotected soft tissues. For this purpose, the TLD was irradiated over a water slab phantom with a photon beam representative of the result of a fluoroscopy beam scattered by a patient. Incident beam angles of 0 degrees and 60 degrees, and lead thicknesses between the TLD and phantom of 0.25 and 0.5 mm Pb were considered. A backscatter correction factor of 1.23 (independent of lead thickness) was calculated comparing the results with those faced in reference conditions (i.e., without lead shield and with an angular incidence of 0 degrees). The corrected dose algorithm was validated in laboratory conditions with dosi-meters irradiated over a thyroid collar and angular incidences of 0 degrees, 40 degrees and 60 degrees, as well as with dosimeters worn by interventional radiologists and cardiologists. The corrected dose algorithm provides a better approach to estimate the equivalent dose to unprotected soft tissues such as eye lenses. Dosimeters that are not shielded from backscatter radiation might underestimate personal equivalent doses when worn over a lead apron and, therefore, should be specifically characterized for this purpose. |
Address |
[Quintero-Quintero, A.; Patino-Camargo, G.] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Valencia, Spain, Email: ccanjuan@gmail.com |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0952-4746 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:000428913900001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
3552 |
Permanent link to this record |
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Author |
Valcarce, A.; Vijande, J.; Richard, J.M.; Garcilazo, H. |
Title |
Stability of Heavy Tetraquarks |
Type |
Journal Article |
Year |
2018 |
Publication |
Few-Body Systems |
Abbreviated Journal |
Few-Body Syst. |
Volume |
59 |
Issue |
2 |
Pages |
9 - 7pp |
Keywords |
|
Abstract |
We discuss the stability of tetraquark systems with two different masses. After some reminders about the stability of very asymmetric QQ (q) over bar(q) over bar tetraquarks, we demonstrate that in the all-heavy limit q -> Q, the system becomes unstable for standard color-additive models. We also analyze the consequences of symmetry breaking for Qq (Q) over bar(q) over bar configurations: we find a kind of metastability between the lowest threshold Q (Q) over bar + q (q) over bar and the highest one, Q (q) over bar + (Q) over barq, and we calculate the width of the resonance. Our results are consistent with the experimental observation of narrow hadrons lying well above their lowest decay threshold. |
Address |
[Valcarce, A.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: valcarce@usal.es; |
Corporate Author |
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Thesis |
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Publisher |
Springer Wien |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
0177-7963 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:000427011200005 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
3574 |
Permanent link to this record |
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Author |
Gimenez-Alventosa, V.; Gimenez, V.; Ballester, F.; Vijande, J.; Andreo, P. |
Title |
Correction factors for ionization chamber measurements with the 'Valencia' and 'large field Valencia' brachytherapy applicators |
Type |
Journal Article |
Year |
2018 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
Volume |
63 |
Issue |
12 |
Pages |
125004 - 10pp |
Keywords |
skin applicator; Valencia applicator; large field Valencia applicator; HDR brachytherap; brachytherapy dosimetry; Monte Carlo |
Abstract |
Treatment of small skin lesions using HDR brachytherapy applicators is a widely used technique. The shielded applicators currently available in clinical practice are based on a tungsten-alloy cup that collimates the source-emitted radiation into a small region, hence protecting nearby tissues. The goal of this manuscript is to evaluate the correction factors required for dose measurements with a plane-parallel ionization chamber typically used in clinical brachytherapy for the 'Valencia' and 'large field Valencia' shielded applicators. Monte Carlo simulations have been performed using the PENELOPE-2014 system to determine the absorbed dose deposited in a water phantom and in the chamber active volume with a Type A uncertainty of the order of 0.1%. The average energies of the photon spectra arriving at the surface of the water phantom differ by approximately 10%, being 384 keV for the 'Valencia' and 343 keV for the 'large field Valencia'. The ionization chamber correction factors have been obtained for both applicators using three methods, their values depending on the applicator being considered. Using a depth-independent global chamber perturbation correction factor and no shift of the effective point of measurement yields depth-dose differences of up to 1% for the 'Valencia' applicator. Calculations using a depth-dependent global perturbation factor, or a shift of the effective point of measurement combined with a constant partial perturbation factor, result in differences of about 0.1% for both applicators. The results emphasize the relevance of carrying out detailed Monte Carlo studies for each shielded brachytherapy applicator and ionization chamber. |
Address |
[Gimenez-Alventosa, V.] Univ Politecn Valencia, CSIC, Ctr Mixto, Inst Instrumentac Imagen Mol I3M, E-46022 Valencia, Spain, Email: Javier.vijande@uv.es |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9155 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000434682500004 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
3609 |
Permanent link to this record |