We study the properties of K and K mesons in nuclear matter at finite temperature from a chiral unitary approach in coupled channels that incorporates the s and p waves of the kaon-nucleon ...interaction. The in-medium solution accounts for Pauli blocking effects, mean-field binding on all the baryons involved, and {pi} and kaon self-energies. We calculate K and K (off-shell) spectral functions and single-particle properties. The K effective mass gets lowered by about -50 MeV in cold nuclear matter at saturation density and by half this reduction at T=100 MeV. The p-wave contribution to the K optical potential, due to {lambda},{sigma}, and {sigma}* excitations, becomes significant for momenta larger than 200 MeV/c and reduces the attraction felt by the K in the nuclear medium. The K spectral function spreads over a wide range of energies, reflecting the melting of the {lambda}(1405) resonance and the contribution of YN{sup -1} components at finite temperature. In the KN sector, we find that the low-density theorem is a good approximation for the K self-energy close to saturation density due to the absence of resonance-hole excitations. The K potential shows a moderate repulsive behavior, whereas the quasiparticle peak is considerably broadened with increasing density andmore » temperature. We discuss the implications for the decay of the {phi} meson at GSI Schwerionen Synchrotron energies as well as in the future Facility for Antiproton and Ion Research project.« less
We study the properties of heavy mesons using a unitarized approach
in a hot pionic medium, based on an effective hadronic theory. The
interaction between the heavy mesons and pseudoscalar Goldstone ...bosons
is described by a chiral Lagrangian at next-to-leading order in the
chiral expansion and leading order in the heavy-quark mass expansion so
as to satisfy heavy-quark spin symmetry. The meson-meson scattering
problem in coupled channels with finite-temperature corrections is
solved in a self-consistent manner. Our results show that the masses of
the ground-state charmed mesons
D(0^-)
D
(
0
−
)
and
D_s(1^-)
D
s
(
1
−
)
decrease in a pionic environment at
T\neq 0
T
≠
0
and they acquire a substantial width. As a consequence, the behaviour of
excited mesonic states (
D_{s0}^*(2317)^\pm
D
s
0
*
(
2317
)
±
and
D_0^*(2300)^{0,\pm}
D
0
*
(
2300
)
0
,
±
),
generated dynamically in our heavy-light molecular model, is also
modified at
T\neq 0
T
≠
0
.
The aim is to test our results against Lattice QCD calculations in the
future.
Strangeness in Neutron Stars Tolos, Laura
EPJ Web of Conferences,
2024, Letnik:
291
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In this contribution I briefly review the dynamics of strange mesons and baryons with dense nuclear matter, paying a special attention to their pres ence in the inner core of neutron stars and the ...consequences for the structure of these compact stars.
•A critical examination of monochloramine standard synthesis conditions has been performed.•A comparative study for determination of monochloramine by using different colorimetric methods has been ...carried out.•Influence of the pH of mobile phase and the volume of sample processed by using IT-SMPE Capillary LC DAD have been investigated and optimized.•A selective and sensitive method for determination of monochlormine in water based in capillary HPLC has been developed.•Better LOD and LOQ were found with respect other procedures for determination of monochloramines.
Due to the difficulties of working with chloramines, a critical examination of monochloramine standard preparation has been performed in order to select the best synthesis conditions. The analyte has been determined by in-tube solid phase extraction coupled to capillary liquid chromatography with UV detection (IT-SPME Capillary LC DAD). Potential factors affecting the response of monochloramine such as the pH of mobile phase and the volume of sample processed by IT-SPME Capillary LC DAD have been investigated and optimized. According to the results of the study, 0.1mL or 4.0mL of sample at neutral pH were loaded in the chromatographic system. A sensitive and selective method has been developed for the determination of monochloramine in water. Validation of the method has been performed. The linear range was 0.09-5mg/L with linear regression coefficients (R2) greater than 0.995. Method reproducibility expressed as relative standard deviation (RSD, %), was lower than 15%. The limits of detection (LODs) were 0.029 and 0.01mg/L by processing 0.100mL or 4mL of the samples, respectively, being below the maximum residues levels allowed for this compound. The sensitivity achieved by the developed method was better than that obtained by the reference method. The developed method was applied to water samples (tap and swimming pool water).
In this contribution we review the dynamics of hyperons with nucleons and nuclear matter, paying a special attention to hypernuclei. We also discuss the presence of hyperons in the inner core of ...neutron stars and the consequences for the structure of these compact stars.
The present status in the field of strange mesons in nuclei and neutron stars is reviewed. In particular, the
K̅N
interaction, that is governed by the presence of the Λ(1405), is analyzed and the ...formation of the
K̅NN
bound state is discussed. Moreover, the properties of
K̅
in dense nuclear matter are studied, in connection with strangeness production in nuclear collisions and kaon condensation in neutron stars.
Display omitted
•A simultaneous immobilization of TMB and HRP on a PDMS support has been carried out.•Two immobilization methods of the enzyme have been tested and compared.•The developed biosensor ...has been applied to H2O2 determination in real samples.•Relative standard deviation of the method was lower than 10%.•This biosensor simplifies significantly the analytical measurements.
An efficient approach to enhance the performance of colorimetric biosensors has been developed. The biosensor is based on the co-immobilization of the reagent 3,3′,5,5′-teramethylbencidine (TMB) and the enzyme horseradish peroxidase (HRP) in a PDMS-TEOS-SiO2NPs support. The HRP, in presence of H2O2, catalyzes the oxidation of TMB, producing a blue color. The generated biosensor, doped with the substrate (TMB) and the enzyme (HRP) (entrapped or adsorbed), has been used to determine H2O2 in real samples. Firstly, the immobilization of TMB and HRP in the composite has been studied in order to find the best suitable configuration. The kinetic parameters Vmax (maximum reaction rate) and Km (substrate affinity) of the different assayed systems have been determined and compared. Secondly, the analytical properties of the H2O2 method have been obtained. From the analytical point of view, no significant differences were observed between the adsorption and entrapment immobilization procedures used for the HRP. This method is simple, inexpensive, highly sensitive and selective for the determination of H2O2, with detection limits of 1.3μM and a good linearity over the range 4.2–72μM. The LOD can be improved to 0.4μM by acidifying the solution with sulphuric acid. Precision was also satisfactory (relative standard deviation, RSD<10%). Results were compared to those obtained by the conventional derivatization method in solution. The developed biosensor is a reagent-release support which significantly simplifies the analytical measurements, because it avoids the need to prepare derivatization reagents and sample-handling, and it allows in situ measurements.
PDF
