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1.
Phys Rev Lett ; 133(9): 092301, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39270180

RESUMEN

This Letter presents the most precise measurement to date of the matter-antimatter imbalance at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV. Using the Statistical Hadronization framework, it is possible to obtain the value of the electric charge and baryon chemical potentials, µ_{Q}=-0.18±0.90 MeV and µ_{B}=0.71±0.45 MeV, with unprecedented precision. A centrality-differential study of the antiparticle-to-particle yield ratios of charged pions, protons, Ω baryons, and light (hyper)nuclei is performed. These results indicate that the system created in Pb-Pb collisions at the LHC is on average baryon-free and electrically neutral at midrapidity.

2.
Phys Rev Lett ; 133(8): 082501, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39241734

RESUMEN

The neutron-rich unbound fluorine isotope ^{30}F_{21} has been observed for the first time by measuring its neutron decay at the SAMURAI spectrometer (RIBF, RIKEN) in the quasifree proton knockout reaction of ^{31}Ne nuclei at 235 MeV/nucleon. The mass and thus one-neutron-separation energy of ^{30}F has been determined to be S_{n}=-472±58(stat)±33(sys) keV from the measurement of its invariant-mass spectrum. The absence of a sharp drop in S_{n}(^{30}F) shows that the "magic" N=20 shell gap is not restored close to ^{28}O, which is in agreement with our shell-model calculations that predict a near degeneracy between the neutron d and fp orbitals, with the 1p_{3/2} and 1p_{1/2} orbitals becoming more bound than the 0f_{7/2} one. This degeneracy and reordering of orbitals has two potential consequences: ^{28}O behaves like a strongly superfluid nucleus with neutron pairs scattering across shells, and both ^{29,31}F appear to be good two-neutron halo-nucleus candidates.

3.
Phys Rev Lett ; 133(7): 072501, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39213556

RESUMEN

Isomer spectroscopy of heavy neutron-rich nuclei beyond the N=126 closed shell has been performed for the first time at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. New millisecond isomers have been identified at low excitation energies, 985.3(19) keV in ^{213}Tl and 874(5) keV in ^{215}Tl. The measured half-lives of 1.34(5) ms in ^{213}Tl and 3.0(3) ms in ^{215}Tl suggest spins and parities 11/2^{-} with the single proton-hole configuration πh_{11/2} as leading component. They are populated via E1 transitions by the decay of higher-lying isomeric states with proposed spin and parity 17/2^{+}, interpreted as arising from a single πs_{1/2} proton hole coupled to the 8^{+} seniority isomer in the ^{A+1}Pb cores. The lowering of the 11/2^{-} states is ascribed to an increase of the πh_{11/2} proton effective single-particle energy as the second νg_{9/2} orbital is filled by neutrons, owing to a significant reduction of the proton-neutron monopole interaction between the πh_{11/2} and νg_{9/2} orbitals. The new ms isomers provide the first experimental observation of shell evolution in the almost unexplored N>126 nuclear region below doubly magic ^{208}Pb.

4.
Phys Rev Lett ; 133(2): 022301, 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-39073970

RESUMEN

The ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum (high p_{T}) hadron trigger in proton-proton and central Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV. A data-driven statistical method is used to mitigate the large uncorrelated background in central Pb-Pb collisions. Recoil jet distributions are reported for jet resolution parameter R=0.2, 0.4, and 0.5 in the range 7

5.
Phys Rev Lett ; 132(22): 222501, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38877923

RESUMEN

The known I^{π}=8_{1}^{+}, E_{x}=2129-keV isomer in the semimagic nucleus ^{130}Cd_{82} was populated in the projectile fission of a ^{238}U beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, E_{x}=2001.2(7) keV, and half-life, T_{1/2}=57(3) ns, of the I^{π}=6_{1}^{+} state based on γγ coincidence information. Furthermore, the half-life of the 8_{1}^{+} state, T_{1/2}=224(4) ns, was remeasured with high precision. The new experimental information, combined with available data for ^{134}Sn and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for ^{132}Sn, a doubly magic nucleus far-off stability. A comparison to analogous information for ^{100}Sn provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.

6.
Phys Rev Lett ; 132(22): 222303, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38877919

RESUMEN

K^{+}K^{-} pairs may be produced in photonuclear collisions, either from the decays of photoproduced ϕ(1020) mesons or directly as nonresonant K^{+}K^{-} pairs. Measurements of K^{+}K^{-} photoproduction probe the couplings between the ϕ(1020) and charged kaons with photons and nuclear targets. The kaon-proton scattering occurs at energies far above those available elsewhere. We present the first measurement of coherent photoproduction of K^{+}K^{-} pairs on lead ions in ultraperipheral collisions using the ALICE detector, including the first investigation of direct K^{+}K^{-} production. There is significant K^{+}K^{-} production at low transverse momentum, consistent with coherent photoproduction on lead targets. In the mass range 1.1

7.
Phys Rev Lett ; 132(16): 162302, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38701458

RESUMEN

The first measurement of the cross section for incoherent photonuclear production of J/ψ vector mesons as a function of the Mandelstam |t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, |y|<0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02 TeV. This rapidity interval corresponds to a Bjorken-x range (0.3-1.4)×10^{-3}. Cross sections are given in five |t| intervals in the range 0.04<|t|<1 GeV^{2} and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a |t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

8.
Phys Rev Lett ; 132(17): 172302, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38728735

RESUMEN

This Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at sqrt[s]=13 TeV. Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of 1.4<|Δη|<1.8 and a transverse momentum of 1

9.
Phys Rev Lett ; 132(8): 082501, 2024 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-38457706

RESUMEN

The structure and decay of the most neutron-rich beryllium isotope, ^{16}Be, has been investigated following proton knockout from a high-energy ^{17}B beam. Two relatively narrow resonances were observed for the first time, with energies of 0.84(3) and 2.15(5) MeV above the two-neutron decay threshold and widths of 0.32(8) and 0.95(15) MeV, respectively. These were assigned to be the ground (J^{π}=0^{+}) and first excited (2^{+}) state, with E_{x}=1.31(6) MeV. The mass excess of ^{16}Be was thus deduced to be 56.93(13) MeV, some 0.5 MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wave function during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2^{+} level presents a far more diffuse neutron-neutron distribution.

10.
ESMO Open ; 9(1): 102219, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38194881

RESUMEN

BACKGROUND: Despite the prognostic relevance of cachexia in pancreatic cancer, individual body composition has not been routinely integrated into treatment planning. In this multicenter study, we investigated the prognostic value of sarcopenia and myosteatosis automatically extracted from routine computed tomography (CT) scans of patients with advanced pancreatic ductal adenocarcinoma (PDAC). PATIENTS AND METHODS: We retrospectively analyzed clinical imaging data of 601 patients from three German cancer centers. We applied a deep learning approach to assess sarcopenia by the abdominal muscle-to-bone ratio (MBR) and myosteatosis by the ratio of abdominal inter- and intramuscular fat to muscle volume. In the pooled cohort, univariable and multivariable analyses were carried out to analyze the association between body composition markers and overall survival (OS). We analyzed the relationship between body composition markers and laboratory values during the first year of therapy in a subgroup using linear regression analysis adjusted for age, sex, and American Joint Committee on Cancer (AJCC) stage. RESULTS: Deep learning-derived MBR [hazard ratio (HR) 0.60, 95% confidence interval (CI) 0.47-0.77, P < 0.005] and myosteatosis (HR 3.73, 95% CI 1.66-8.39, P < 0.005) were significantly associated with OS in univariable analysis. In multivariable analysis, MBR (P = 0.019) and myosteatosis (P = 0.02) were associated with OS independent of age, sex, and AJCC stage. In a subgroup, MBR and myosteatosis were associated with albumin and C-reactive protein levels after initiation of therapy. Additionally, MBR was also associated with hemoglobin and total protein levels. CONCLUSIONS: Our work demonstrates that deep learning can be applied across cancer centers to automatically assess sarcopenia and myosteatosis from routine CT scans. We highlight the prognostic role of our proposed markers and show a strong relationship with protein levels, inflammation, and anemia. In clinical practice, automated body composition analysis holds the potential to further personalize cancer treatment.


Asunto(s)
Aprendizaje Profundo , Neoplasias Pancreáticas , Sarcopenia , Humanos , Pronóstico , Sarcopenia/complicaciones , Músculo Esquelético/patología , Estudios Retrospectivos , Composición Corporal , Neoplasias Pancreáticas/complicaciones , Neoplasias Pancreáticas/patología
11.
Case Reports Hepatol ; 2024: 5556907, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38249623

RESUMEN

Background: Acute liver injury is a life-threatening condition with disparate aetiology. Swift and adequate interdisciplinary treatment is essential to assure the best possible outcomes in these patients. Investigations to identify the cause of the condition and the implementation of quick and appropriate treatment can be lifesaving. Case Presentation. In October 2022, an otherwise healthy 66-year-old male presented at the University Hospital Essen with acute liver injury following an inclisiran injection for hypercholesterinaemia. Four weeks following admission, the patient fully recovered after initially receiving short-term cortisol therapy and open albumin (OPAL) dialysis, and the indices of liver, kidney, and coagulation function were normal at discharge. Conclusion: This is to our knowledge the first reported acute liver injury due to an inclisiran injection. Cortisol in combination with OPAL dialysis is an effective method for the treatment of acute liver injury caused by inclisiran injury, and in this case, it led to a near-complete reversal of the acute liver injury at the time of discharge.

12.
Phys Rev Lett ; 131(21): 212501, 2023 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-38072612

RESUMEN

The cluster structure of the neutron-rich isotope ^{10}Be has been probed via the (p,pα) reaction at 150 MeV/nucleon in inverse kinematics and in quasifree conditions. The populated states of ^{6}He residues were investigated through missing mass spectroscopy. The triple differential cross section for the ground-state transition was extracted for quasifree angle pairs (θ_{p},θ_{α}) and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using successively the Tohsaki-Horiuchi-Schuck-Röpke product wave function and the wave function deduced from antisymmetrized molecular dynamics calculations. The remarkable agreement between calculated and measured cross sections in both shape and magnitude validates the molecular structure description of the ^{10}Be ground-state, configured as an α-α core with two valence neutrons occupying π-type molecular orbitals.

14.
Nature ; 620(7976): 965-970, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37648757

RESUMEN

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10-21 s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.

16.
Phys Rev Lett ; 130(17): 172501, 2023 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-37172241

RESUMEN

We report on the first proton-induced single proton- and neutron-removal reactions from the neutron-deficient ^{14}O nucleus with large Fermi-surface asymmetry S_{n}-S_{p}=18.6 MeV at ∼100 MeV/nucleon, a widely used energy regime for rare-isotope studies. The measured inclusive cross sections and parallel momentum distributions of the ^{13}N and ^{13}O residues are compared to the state-of-the-art reaction models, with nuclear structure inputs from many-body shell-model calculations. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively. These multiple reaction mechanisms should be considered in analyses of inclusive one-nucleon removal cross sections measured at intermediate energies for quantitative investigation of single-particle strengths and correlations in atomic nuclei.

17.
J Cancer Res Clin Oncol ; 149(8): 5085-5094, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36334155

RESUMEN

PURPOSE: Systemic-inflammatory response parameters (SIR) are known prognostic markers in different tumour entities, but have not been evaluated in patients with iCCA treated with systemic chemotherapy. Therefore, we evaluated the impact of different SIR markers on the clinical course of patients with advanced iCCA treated at our center. METHODS: SIR markers were retrospectively evaluated in 219 patients with iCCA at the West-German-Cancer-Center Essen from 2014 to 2019. Markers included neutrophil/lymphocyte ratio (NLR), lymphocyte/monocyte ratio (LMR), CRP, and the modified Glasgow-Prognostic-Score (mGPS), which were correlated with clinico-pathological findings, response to chemotherapy (ORR), progression-free (PFS) and overall survival (OS) using Kaplan-Meier analyses, and Cox proportional models. RESULTS: Median overall survival (OS) of the entire cohort was 14.8 months (95% CI 11.2-24.4). Median disease-free survival (DFS) in 81 patients undergoing resection was 12.3 months (95% CI 9.7-23.1). The median OS from start of palliative CTX (OSpall) was 10.9 months (95% 9.4-14.6). A combined Systemic Inflammatory Score (SIS) comprising all evaluated SIR markers correlated significantly with ORR, PFS, and OSpall. Patients with a high SIS (≥ 2) vs. SIS 0 had a significantly inferior OSpall (HR 8.7 95% CI 3.71-20.38, p < 0.001). Multivariate analysis including known prognostic markers (ECOG, CA19-9, LDH, and N- and M-status) identified the SIS as an independent prognostic factor. CONCLUSIONS: Inflammatory markers associate with inferior survival outcomes in patients with iCCA. A simple SIS may guide treatment decisions in patients treated with systemic chemotherapy.


Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Humanos , Pronóstico , Estudios Retrospectivos , Inflamación/patología , Colangiocarcinoma/tratamiento farmacológico , Colangiocarcinoma/patología , Linfocitos/patología , Conductos Biliares Intrahepáticos , Neoplasias de los Conductos Biliares/tratamiento farmacológico , Neoplasias de los Conductos Biliares/patología
18.
Phys Rev Lett ; 131(24): 242501, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38181133

RESUMEN

We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

19.
Phys Rev Lett ; 129(21): 212502, 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36461972

RESUMEN

The new isotope ^{39}Na, the most neutron-rich sodium nucleus observed so far, was discovered at the RIKEN Nishina Center Radioactive Isotope Beam Factory using the projectile fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon on a beryllium target. Projectile fragments were separated and identified in flight with the large-acceptance two-stage separator BigRIPS. Nine ^{39}Na events have been unambiguously observed in this work and clearly establish the particle stability of ^{39}Na. Furthermore, the lack of observation of ^{35,36}Ne isotopes in this experiment significantly improves the overall confidence that ^{34}Ne is the neutron dripline nucleus of neon. These results provide new key information to understand nuclear binding and nuclear structure under extremely neutron-rich conditions. The newly established stability of ^{39}Na has a significant impact on nuclear models and theories predicting the neutron dripline and also provides a key to understanding the nuclear shell property of ^{39}Na at the neutron number N=28, which is normally a magic number.

20.
Phys Rev Lett ; 129(17): 172701, 2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36332266

RESUMEN

The ß-delayed one- and two-neutron emission probabilities (P_{1n} and P_{2n}) of 20 neutron-rich nuclei with N≥82 have been measured at the RIBF facility of the RIKEN Nishina Center. P_{1n} of ^{130,131}Ag, ^{133,134}Cd, ^{135,136}In, and ^{138,139}Sn were determined for the first time, and stringent upper limits were placed on P_{2n} for nearly all cases. ß-delayed two-neutron emission (ß2n) was unambiguously identified in ^{133}Cd and ^{135,136}In, and their P_{2n} were measured. Weak ß2n was also detected from ^{137,138}Sn. Our results highlight the effect of the N=82 and Z=50 shell closures on ß-delayed neutron emission probability and provide stringent benchmarks for newly developed macroscopic-microscopic and self-consistent global models with the inclusion of a statistical treatment of neutron and γ emission. The impact of our measurements on r-process nucleosynthesis was studied in a neutron star merger scenario. Our P_{1n} and P_{2n} have a direct impact on the odd-even staggering of the final abundance, improving the agreement between calculated and observed Solar System abundances. The odd isotope fraction of Ba in r-process-enhanced (r-II) stars is also better reproduced using our new data.

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