Medium Modifications Research Articles

Jet tomography in high-energy nuclear collisions

When an energetic parton traversing the QCD medium, it may suffer multiple scatterings and lose energy. This jet quenching phenomenon may lead to the suppression of leading hadron productions as well as medium modifications of full jet observables in heavy-ion collisions. In this talk we discuss the nuclear modificationfactors and yield ratios of identified meson such as η, ρ0, φ, ω, and $ K_{\rm{S}}^0 $ as well as π meson at large pT in A+A collisions at the next to-leading order (NLO) with high-twist approach of parton energy loss. Then we discuss a newly developed formalism of combing NLO matrix elements and parton shower (PS) for initial hard production with parton energy loss in the QGP, and its application in investigating massivegauge boson(Z0/W±)tagged jet productions and b $ \bar {b} $ dijet correlations in Pb+Pb at the LHC.

Effective field theory calculations in open charm and charmonium production in media

Heavy quarkonium related observables are very useful to obtain information about the medium created in relativistic heavy ion collisions. The interaction of charmonium or bottomonium with the hot QCD medium created in these collisions can be efficiently described with the use of non-relativistic Effective Field Theories. In this proceedings, I will review recent progress in understanding quarkonium dynamics in a thermal medium with the use of potential non-relativistic QCD (pNRQCD). First, I will discuss the medium modifications of the decay width and the binding energy. Using pNRQCD power counting it is possible to identify in which temperature regimes a potential model can describe these modifications and what is the dominant physical process behind the thermal corrections in each case. After that, I will discuss the combination of pNRQCD with open quantum systems techniques. This allows making predictions about the nuclear modification factor that can be compared with experimental measurements.

Charmonium states in strong magnetic fields

The medium modifications of the masses of the charmonium states (J/$\psi$, $\psi$(3686) and $\psi$(3770)) in asymmetric nuclear matter in the presence of strong magnetic fields are studied using an effective chiral model. The mass modifications arise due to medium modifications of the scalar dilaton field, which simulates the gluon condensates of QCD within the effective hadronic model. The effects due to the magnetic field as well as isospin asymmetry are observed to be appreciable at high densities for the charmonium states, which can have consequences, e,g, in the production of the open charm mesons and the charmonium states, in the asymmetric heavy ion collisions at the compressed baryonic matter (CBM) experiments at the future facility at GSI. The presence of magnetic field leads to Landau quantization of the energy levels of the proton in the asymmetric nuclear matter. The effects of the anomalous magnetic moments of the proton and neutron on the masses of the charmonium states are studied and are observed to lead to larger masses of the charmonium states, as compared to when these effects are not taken into account.

STUDY AND CHARACTERIZATION GROWTH OF FOUR MICROALGAE SPECIES AND TEST ANTIMICROBIAL ACTIVITY

Abstract
 In this study to the growth characteristics of microalgae (Dunaliella salina, Nannochloropsis oculata, Tetrasel mis chuii & Chaetoceros calcitrans), in different mediums, namely Bold’s Basal Medium (BBM) and BBM modification of sea water. The results obtained from microalgae (N.oculata, T.chuii, C.calcitrans) are better grown on BBM media while microlaga D.salina grows well on BBM modification of sea water. Microalgae biomass is extracted by maceration method in hexane and methanol solvents. Test bacteria used gram positive (Staphylococcus aureus) and gram negative (Escherichia coli). Inhibitory zone diameter results were compared with antimicrobial sensitivity tests according to Clinical and Laboratory Standards Institute (CLSI). From the results of microalgae hexane and methanol extract antibacterial activity tests (D.salina, N.oculata, T.chuii, C.calcitrans) showed that the extract was not too sensitive to inhibit bacterial growth.
 
 Keywords: microalgae, medium, antimicrobial

Medium modification of the shape of small-radius jets in central Pb-Pb collisions at sqrt{s_{mathrm{NN}}}=2.76 TeV

We present the measurement of a new set of jet shape observables for track-based jets in central Pb-Pb collisions at sqrt{s_{mathrm{NN}}}=2.76 TeV. The set of jet shapes includes the first radial moment or angularity, g; the momentum dispersion, pTD; and the difference between the leading and sub-leading constituent track transverse momentum, LeSub. These observables provide complementary information on the jet fragmentation and can constrain different aspects of the theoretical description of jet-medium interactions. The jet shapes were measured for a small resolution parameter R = 0.2 and were fully corrected to particle level. The observed jet shape modifications indicate that in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by PYTHIA calculations, which were validated with the measurements of the jet shapes in proton-proton collisions at sqrt{s}=7 TeV. The comparison of the measured distributions to templates for quark and gluon-initiated jets indicates that in-medium fragmentation resembles that of quark jets in vacuum. We further argue that the observed modifications are not consistent with a totally coherent energy loss picture where the jet loses energy as a single colour charge, suggesting that the medium resolves the jet structure at the angular scales probed by our measurements (R = 0.2). Furthermore, we observe that small-R jets can help to isolate purely energy loss effects from other effects that contribute to the modifications of the jet shower in medium such as the correlated background or medium response.

Effect of anti-apoptotic drug Z-VAD-FMK on in vitro viability of dog follicles

It is recognized that ovarian follicular atresia is associated with apoptosis, and the most important effector of cell death is caspase-3. The aim of this study was to investigate the influence of anti-apoptotic drug Z-VAD-FMK on in vitro follicle growth in the domestic dog. Ovaries were obtained from peri-pubertal and adult domestic dogs, and cortical fragments recovered and incubated on 1.5% (w/v) agarose gel blocks within a 24-well culture plate containing Minimum Essential Medium Eagle-Alpha Modification (αMEM) supplemented with 4.2 μg/mL insulin, 3.8 μg/mL transferrin, 5 ng/mL selenium, 2 mM L-glutamine, 100 μg/mL of penicillin G sodium, 100 μg/mL of streptomycin sulfate, 0.05 mM ascorbic acid, 10 ng/mL of FSH and 0.1% (w/v) polyvinyl alcohol in humidified atmosphere of 5% CO2 and 5% O2. The cortices were randomly allocated in six treatments: 1) 10 ng/mL EGF (EGF V0); 2) 10 ng/mL of EGF plus 1 mM Z-VAD-FMK (EGF V1); 3) 10 ng/mL of EGF and 10 mM Z-VAD-FMK (EGF V10); 4) 1 mM Z-VAD-FMK; 5) 10 mM Z-VAD-FMK and (6) no EGF and Z-VAD-FMK supplementation (Control). The cortices were processed for histology and assessed for viability (based on morphology), density of structurally normal follicles, and diameter immediately after collection (non-culture Control) or after 3 or 7 days of in vitro incubation. Evaluation of mRNA expression of Cas3 in fresh cortices and those incubated for 3 days was performed using real-time PCR. Histological analysis revealed that in vitro incubation decreased (P < 0.05) follicle viability and density compared to the fresh, non-culture control. Addition of 10 μM of Z-VAD-FMK alone to the culture medium sustained follicle viability at Day 3, but did not impact follicle diameter when compared to the other treatment groups (p < 0.001); however, the beneficial benefit of this anti-apoptotic drug diminished after 7 days of incubation. Furthermore, Z-VAD-FMK supplementation did not impact Cas3 expression. The findings demonstrated that dog ovarian tissues are highly susceptible to in vitro incubation and Z-VAD-FMK supported short-term survival of dog follicles enclosed within the ovarian cortex.

Future outlook of plant growth regulators application influencing callus induction from different type explant &lt;i&gt;Hyoscyamus muticus&lt;/i&gt; L. &lt;i&gt;in vitro&lt;/i&gt;

The article shows the results concerning the problem of the influence of the hormonal composition of the medium on callus induction in isolated from different explants of Egyptian henbane areas (on the example of Hyoscyamus muticus L.). The authors study 11 variants of Murashige and Skoog medium supplemented with different concentrations and combination of auxins and cytokinins. It was important to find nutrient medium modification of Murashige and Skoog for callus induction. The article describes the fact that callus formation from different explant types of Hyoscyamus muticus L. in vitro was observed on Murashige and Skoog medium fortified with benzylaminopurine and naphthylacetic acid. It shows that the maximum callus induction was observed from root explants on Murashige and Skoog's medium supplemented with 0.5 mg/l of benzylaminopurine and 1.0 mg/l of naphthylacetic acid. And minimal callus formation was observed in the area with benzylaminopurine. Callus induction of leaf and stem explants both on the hormone-free nutrient medium and with the benzylaminopurine only was not observed. Thus, the results show that the frequency of callus formation with culturing root segment is higher compared to leaf and stem segment explants (on the example of Egyptian henbane in culture in vitro). This work aims to inducing callus formation from various explants of Egyptian henbane, which can be used for plant regeneration or as a source for in vitro production of secondary metabolites.

Impact of medium modifications of the nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter

Impact of the in-medium modified nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter is studied by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field model and the quark-meson coupling model are respectively adopted for the in-medium effective nucleon mass and nucleon form factors. We find that the cross sections of neutrino scattering in cold nuclear medium decreases when the in-medium modification of the nucleon weak and electromagnetic form factors are taken into account. This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density. The enhancement of the neutrino mean free path is estimated to be about 10--40\% compared with the values obtained without the medium modification of the nucleon form factors, and the enhancement is expected to accelerate the cooling of neutron stars.

Open bottom mesons in asymmetric nuclear matter in the presence of strong magnetic fields

The modifications of the masses of the $B$ and $\bar B$ mesons in asymmetric nuclear matter in the presence of strong magnetic fields, are investigated using a chiral effective model. The medium modifications of these open bottom mesons arise due to their interactions with the scalar mesons and the nucleons. In the magnetized nuclear matter, the proton has contributions from the Landau levels. In the chiral effective model, the masses of the $B$ and $\bar B$ are calculated from the leading term, namely the vectorial Weinberg Tomozawa term as well as from the next to leading order contributions, i.e., due to the scalar exchange and the range terms. Due to the Weinberg-Tomozawa term, the $\bar B$ mesons experience an attractive interaction in the symmetric nuclear matter, whereas the $B$ mesons have a repulsive interaction. Inclusion of the contributions from the scalar exchange and the range terms as well, leads to drop of the masses of both $B$ and $\bar B$ mesons. The effect of the isospin asymmetry breaks the mass degeneracy of the $B^+$ and $B^0$ (as well as of the $B^-$ and $\bar {B^0}$) mesons, and its effect is observed to be large at high densities. The effects of anomalous magnetic moments of the nucleons are taken into account in the present study of the masses of the open bottom mesons in magnetized nuclear matter.

D mesons in strongly magnetized asymmetric nuclear matter

The medium modifications of the open charm mesons ($D$ and $\bar D$) are studied in isospin asymmetric nuclear matter in the presence of strong magnetic fields, using a chiral effective model. The mass modifications of these mesons in the effective hadronic model, arise due to their interactions with the protons, neutrons and the scalar mesons (non-strange isoscalar $\sigma$, strange isoscalar, $\zeta$ and non-strange isovector, $\delta$), in the magnetized nuclear matter. In the presence of magnetic field, for the charged baryon, i.e., the proton, the number density as well as the scalar density have contributions due to the summation over the Landau energy levels. For a given value of the baryon density, $\rho_B$, and isospin asymmetry, the scalar fields are solved self consistently from their coupled equations of motion. The modifications of the masses of the $D$ and $\bar D$ mesons are calculated, from the medium modifications of the scalar fields and the nucleons. The effects of the anomalous magnetic moments of the nucleons on the masses of the open charm mesons are also investigated in the present work. The effects of isospin asymmetry as well as of the anomalous magnetic moments are observed to be prominent at high densities for large values of magnetic fields.

Sensitivity of jet substructure to jet-induced medium response

Jet quenching in heavy ion collisions is expected to be accompanied by recoil effects, but unambiguous signals for the induced medium response have been difficult to identify so far. Here, we argue that modern jet substructure measurements can improve this situation qualitatively since they are sensitive to the momentum distribution inside the jet. We show that the groomed subjet shared momentum fraction zg, and the girth of leading and subleading subjets signal recoil effects with dependencies that are absent in a recoilless baseline. We find that recoil effects can explain most of the medium modifications to the zg distribution observed in data. Furthermore, for jets passing the Soft Drop Condition, recoil effects induce in the differential distribution of subjet separation ΔR12 a characteristic increase with ΔR12, and they introduce a characteristic enhancement of the girth of the subleading subjet with decreasing zg. We explain why these qualitatively novel features, that we establish in Jewel+Pythia simulations, reflect generic physical properties of recoil effects that should therefore be searched for as telltale signatures of jet-induced medium response.

Low-mass dielectrons in pp, p–Pb and Pb–Pb collisions measured by the ALICE Experiment

Dielectrons produced in ultra-relativistic heavy-ion collisions at the LHC provide a unique probe of the system evolution as they are unperturbed by final-state interactions. The dielectron continuum is extremely rich in physics sources: on top of ordinary Dalitz and resonance decays of pseudoscalar and vector mesons, thermal black-body radiation is of particular interest as it carries information about the temperature of the hot and dense system created in such collisions. The dielectron invariant-mass distribution is furthermore sensitive to medium modifications of the spectral function of short-lived vector mesons that are linked to the potential restoration of chiral symmetry at high temperatures. Correlated electron pairs from semi-leptonic charm and beauty decays provide complementary information about the heavy-quark energy loss.

Medium modification of strange hadronic resonances at SIS, RHIC and LHC energies

The properties of strange pseudoscalar and vectors mesons as well as strange baryon resonances in dense matter are reviewed. Some open questions on the properties of strange hadrons in medium are addressed, such as the experimental signatures of inmedium effects coming from the hadronic phase on the final observables in heavy-ion collisions for the experimental conditions at SIS, RHIC and LHC energies.

Heavy Ion Acceleration at J-PARC

J-PARC, the Japan Proton Accelerator Research Complex, is an accelerator, which provides a high-intensity proton beam. Recently as a very attractive project, the acceleration of heavy ions produced by supplementary ion sources, called J-PARC-HI, is seriously contemplated by domestic as well as international communities. The planned facility would accelerate heavy ions up to U92+ with a beam energy 20 AGeV ([see formula in PDF] of 6.2 AGeV). The highlight of the J-PARC-HI project is its very high beam rate up to ~1011 Hz, which will enable the study of very rare events. Taking advantage of this high intensity, J-PARC-HI will carry out frontier studies of new and rare observables in this energy region: (i) nuclear medium modification of chiral property of vector mesons through low-mass di-lepton signal, (ii) QCD critical pointcharacterization through event-by-event fluctuation signals of particle production, (iii) systematic measurements related to the equation of state through collective flow signal or two-particle momentum correlation signal, or (iv) the search of hyper nuclei with multi strangeness including or exceeding S = 3. The current plan of J-PARC-HI aims to carrying out the first experimental measurements in 2025.

Improving In Vitro Somatic Embryos Production of Medjool and Khalas Date Palm Cultivars via Modification of Ammonium and Potassium Nitrate

Date palm is one of the most economically powerful fruit tree grown in Egypt. Although Egypt tops the list of date's product in the world. Egyptian date palm industry suffers from many constraints. Low-quality varieties and limited conventional propagation methods are the main obstacles. Extension of date palm plantations in various areas of Egypt and replanting trees to compensate loss due to diseases or human factors are reduced expected to lack adequate planting materials. The knowledge of the interplay between some fundamental medium parameters allows not only the optimization of the micropropagation system but also gives models to investigate and rationalize the process of induction and development of somatic embryogenesis itself. In vitro growth and development of produced embryos and plantlets has been improved by using of full MS salt strength. MS medium modification of some nutrients concentrations, i.e. NH4NO3(1237.5 mg/l) which recorded (13.20 and 9.60 embryos/explant for Medjool and Khalas respectively) at the end of three subculture. KNO3 which gave a higher score of mature somatic embryos (14.40 and 10.00 embryo/culture for Medjool and Khalas respectively) was obtained with 1425 mg/l KNO3 after three subcultures as compared to those obtained from any other treatment combination. The morphological response of somatic embryos production is controlled by some internal factors that fall under the influence of the genetic make-up of the plant and specialized for each genotype that is responsible for the production of somatic embryos (Medjool and Khalas cultivars). The genetic make-up is a decisive factor during somatic embryos production. There are differences between the two cultivars named, Medjool and Khalas. The produced somatic embryos at germination stage were transferred from the two experiments namely ammonium nitrate and potassium nitrate to multiplication and rooting stages for more in vitro growth for 12 weeks at three re-cultures. Individual shoots were cultured on modified MS basal medium in addition to IBA (1.0 mg/l), sucrose (30 g/l) and solidified with phyto-agar (8.0 g/l) for more in vitro growth and development. In vitro plantlets were transferred to acclimatization stage in plastic pots 5*18 cm diameter containing peatmoss, perlite and washed sand at equal volume. In vitro date palm plantlets produced from rooting stage grow well in the greenhouse during acclimatization stage without morphological abnormality. The growth and development of Medjool cultivar were better than Khalas during in vitro culture and ex vitro acclimatization.

Jet-hadron correlations relative to the event plane at the LHC with ALICE

In ultra relativistic heavy-ion collisions at the Large Hadron Collider (LHC), conditions are met to produce a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP). Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. The outgoing partons scatter and interact with the medium, leading to a manifestation of medium modifications of jets in the final state, known as jet quenching. Within the framework of perturbative QCD, jet production is well understood in pp collisions. We use jets measured in pp interactions as a baseline reference for comparing to heavy-ion collision systems to detect and study jet quenching. The jet quenching mechanism can be studied through the angular correlations of jets with charged hadrons and is examined in transverse momentum (pT) bins of the jets, pT bins of the associated hadrons, and as a function of collision centrality. A robust and precise background subtraction method is used in this analysis to remove the complex, flow dominated, heavy-ion background. The analysis of angular correlations for different orientations of the jet relative to the event plane allows for the study of the path-length dependence of medium modifications to jets. The event plane dependence of azimuthal angular correlations of charged hadrons with respect to the axis of an R=0.2 reconstructed full (charged + neutral) jet in Pb–Pb collisions at sNN=2.76 TeV in ALICE is presented. Results are compared for three angular bins of the jet relative to the event plane in mid-peripheral events. The yields relative to the event plane are presented and then quantified through yield ratio calculations. The results show no significant path-length dependence on the medium modifications.

Measuring medium-induced gluons via jet grooming

Jet substructure observables and applications of jet grooming techniques in heavy-ion collisions are still in its infancy and provide new alleys for studying medium modifications of perturbative degrees of freedom. We note that these measurements, given the right transverse momentum range, can be uniquely sensitive to rare medium-induced emissions inside of the jet cone. This corresponds to an infrared enhancement that would, for instance, affect the distribution of the groomed momentum-sharing variable zg measured using the SoftDrop procedure.

Measurements of the dielectron continuum in pp, p-Pb and Pb-Pb collisions with ALICE at the LHC

Dielectrons produced in ultra-relativistic heavy-ion collisions provide a unique probe of the whole system evolution as they are unperturbed by final-state interactions. The dielectron continuum is extremely rich in physics sources: thermal radiation is of particular interest as it carries information about the temperature of the hot and dense system created in such collisions. The dielectron invariant mass distribution is sensitive to medium modifications of the spectral function of vector mesons that are linked to the potential restoration of chiral symmetry. Correlated electron pairs from semi-leptonic charm and beauty decays provide information about the heavy-quark energy loss.A summary of the LHC Run-1 preliminary results in all three collisions systems (pp, p-Pb and Pb-Pb) is presented. Furthermore, the status of the ongoing Run-2 analyses is discussed with a focus on pp collisions collected with a high charged-particle multiplicity trigger, on new analysis methods to separate prompt from non-prompt sources, and on the usage of machine learning methods for background rejection.

The different energy loss mechanisms of inclusive and b-tagged reconstructed jets within ultra-relativistic heavy-ion collisions

The phenomenon of jet quenching provides essential information about the properties of hot and dense matter created in ultra-relativistic heavy-ion collisions. Recent results from experiments at the Large Hadron Collider (LHC) show evidence for an unexpectedly similar suppression of both light and heavy flavor jets. Furthermore, the role of radiative energy loss of heavy quarks is still under active discussion within the theoretical community. By employing the parton cascade Boltzmann Approach to Multi-Parton Scatterings (BAMPS), which numerically solves the 3+1 D Boltzmann equation both for light and heavy flavor partons, we calculate the nuclear modification factor of inclusive and b-tagged reconstructed jets in 0–10% central sLHC=2.76 A TeV Pb + Pb collisions. Based on perturbative QCD cross sections we find a suppression of both light and heavy flavor jets. While the inclusive jets are slightly too strong suppressed within Bamps in comparison with data, both elastic + radiative and only elastic interactions lead to a realistic b-tagged jet suppression. To further investigate light and heavy flavor energy loss we predict the R dependence of inclusive and b-tagged jet suppression. Furthermore, we propose the medium modification of b-tagged jet shapes as an observable for discriminating between different heavy quark energy loss scenarios.

Magnetic moments of octet baryons in hot and dense nuclear matter

We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within the chiral SU(3) quark mean field model. Further, for better insight into the medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence quarks, sea quarks and the sea orbital angular momentum of sea quarks. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.