New aspects of the Hadron and Astro/Nuclear Physics

5 Nov 2018, 09:00 → 10 Nov 2018, 12:10 Asia/Tashkent

National University of Uzbekistan

Ulugbek Yakhshiev (Inha University, Incheon) , Yousuf Musakhanov (National University of Uzbekistan (NUUZ), Tashkent)

Brief Information

The National University of Uzbekistan (NUU, Tashkent, Uzbekistan) together with Inha University in Tashkent (IUT, Tashkent, Uzbekistan) and Inha University (IU, Incheon, Korea) organizing the International workshop “New aspects of the Hadron and Astro/Nuclear Physics”. The workshop will be an official international event devoted to the 100 years celebration of National University of Uzbekistan and will concentrate on the following scientific topics:

• Nonperturbative QCD, Confinement Problem,

• Heavy-Light and Heavy-Quark Systems,

• Strangeness Physics, Few-Body Systems,

• Matter under Extreme (high density and temperature) Conditions,

• Heavy-Ion Collisions, Synthesis of Superheavy Elements,

• Nuclear Astrophysics.

The workshop will be held at the Conference hall of Physics Department at the National University of Uzbekistan during the period November 5 (Monday) – November 10 (Saturday), 2018.

The workshop aim is to bring together theoreticians and experimentalists to discuss the modern problems of the hadron, nuclear and nuclear astrophysics. We encourage participation of young scientists, postdocs, PhD and master students.

Working language of the workshop will be English.

Organizing committee

• Bakhodir Irgaziev (NUU) 
• Zokirjon Kanokov (NUU, scientific secretary)
• Hyun-Chul Kim (Inha University)
• Yousuf Musakhanov (chair, NUU)
• Alisher Sanetullaev (IUT)
• Ulugbek Yakhshiev (co-chair, Inha University)
• Rakhim Yarmukhamedov (NUU)

Sponsored by 

Monday, 5 November

Registration at Physics Department

Reception at Physics Department

Tuesday, 6 November

Registration

Opening ceremony

1 Welcome speech by President of Academy of Sciences of Uzbekistan

Speaker: Prof. Bekhzod Yuldashev (Academy of Sciences of Uzbekistan)

2 Welcome speech by Rector of National University of Uzbekistan

Speaker: Prof. Avazjon Marakhimov (National University of Uzbekistan)

3 Welcome speech by Rector of Inha University in Tashkent

Speaker: Mr Muzaffar Djalalov (Inha University in Tashkent)

Hadron Physics I

4 Yc-N dibaryon resonances in the phenomenological potential model

Two-body $J^{\pi}= 0^+$, $1^+$ and $2^+$ resonances of the $Y_c$ ($=\Lambda_c$, $\Sigma_c$, or $\Sigma_c^*$) and N systems are analyzed by the use of the complex scaling method. We employ the $Y_c N$ phenomenological potentials, which are composed of the long-range meson-exchange force and the short-range quark exchange force. We find four Feshbach-type resonance states slightly below the $\Sigma_c N$ or $\Sigma_c^* N$ threshold. It is found that the four resonances form two pairs of the heavy-quark doublets in agreement with the heavy quark spin symmetry.

Speaker: Prof. Makoto Oka (ASRC, Japan Atomic Energy Agency)

OKA-TAashkent-11-06-f.pdf

5 Monopoles and Confinement: new results and state of the art.

It is shown that the existence and the creation of a monopole in Non Abelian Gauge Theories are gauge invariant and Abelian Projection independent concepts.
This puts on a firmer basis the construction of an order parameter for confinement.It also suggests a reinterpretation of old lattice data on monopoles.

Speaker: Prof. Adriano Di Giacomo (Pisa University and INFN)

TashDiGiacomo.pdf

Coffee break

Hadron Physics I

6 Skyrmions and Kaon-Nucleon interactions

We investigate kaon-nucleon interactions in the Skyrme model with the new quantization method. It is based on the bound state approach but is more suited to the weakly bound system. The spatially extended structure of the nucleon as a soliton enables to express the interaction as an $r$-dependent potential. We find that for the isospin 0 antikaon-nucleon system the potential consists of an attractive pocket in the intermediate range and of short range repulsion, resulting in a weakly bound state corresponding to the $\Lambda$(1405). The method is extended to the coupling to $\pi-\Sigma$ channel for a realistic description of the kaon-nucleon system as well as hyperon resonances.

Speaker: Prof. Atsushi Hosaka (RCNP, Osaka University)

2018_1105_Tashkent.pdf

Lunch

Hadron Physics II

7 Status of LAMPS at RAON for nuclear symmetry energy

A new radioactive ion beam accelerator RAON is being constructed at the Institute for Basic Science (IBS) in Korea. Among various experimental devices, the large-acceptance multipurpose spectrometer (LAMPS) will be available in the high-energy experimental hall at RAON. The main goal of the LAMPS detector system is to investigate the nuclear equation of state and symmetry energy at supra-saturation densities, which are essential to understand the effective nuclear interactions and several astrophysical objects like neutron stars. In this presentation, various promising observables at RAON that are sensitive to the nuclear symmetry energy are going to be discussed. Then, the status of the development and construction of the detector elements, in particular the time-projection chamber (TPC) and the forward neutron detector array, for the LAMPS setup will be discussed.

Speaker: Prof. Byungsik Hong (Korea University)

Hong_v1.pdf

8 Short range interaction in pi J/psi-DDbar* channel

Recently, the study of the exotic hadron is of current interest in the Nuclear and Hadron physics. In particular, the charged quarkonia, such as Zc(3900), having the genuinely exotic structure attract a lot of interest. The exotic states near the hadron-hadron threshold have been considered to be a hadronic molecule, while the hadron-hadron interaction is not established yet in the heavy flavor sectors. In this study, we focus on the interaction in the pi J/psi-DDbar* coupled-channel. The short-range interaction is described by the quark exchange diagram. We also find the difference between the results of the meson exchange picture and the quark exchange one.

Speaker: Dr Yasuhiro Yamaguchi (RIKEN)

11_6_Uzbekistan_yamaguchi.pdf

Coffee break

Student Session I

9 Hadronic Paschen-Back effect in P-wave charmonia under strong magnetic fields

QCD dynamics under a strong magnetic field is of great interest to the field of relativistic heavy-ion collisions and magnetars. In this talk, I will discuss a new effect we recently found in Ref.[1], 'Hadronic Paschen-Back effect (HPBE)', which is analogous to the Paschen-Back effect observed in atomic physics.
This effect is induced by the interplay between a strong magnetic field and finite orbital angular momenta in hadronic systems. It allows the wave functions to drastically deform and leads to anisotropic decays. Such a decay gives a possibility to measure the strength of the magnetic field in heavy-ion collision at LHC, RHIC and SPS, which has not experimentally been measured. As an example of HPBE, I will report our results [1] of the mass spectra, wave functions, and mixing ratios of P-wave charmonia in a wide range of magnetic fields by using the potential model and a numerical few-body technique. Furthermore, I will talk about a systematic study for the radiative decays of P-wave quarkonia by HPBE based on potential non-relativistic QCD in Ref.[2].

[1] S. Iwasaki, M. Oka, K. Suzuki, T. Yoshida, “Hadronic Paschen-Back effect,” arXiv:1802.04971
[2] S. Iwasaki, K. Suzuki, “Quarkonium radiative decays from the Hadronic Paschen-Back effect,” Phys. Rev. D98, 054017 (2018)

Speaker: Mr Sachio Iwasaki (Tokyo Institute of Technology & Japan Atomic Energy Agency)

Tashkent2018_Iwasaki_Sachio.pdf

10 Dynamical gluon mass at non-zero temperature in instanton vacuum model

Speaker: Mr Shirinbek Baratov (National University of Uzbekistan)

Baratov Sh.pdf

11 Heavy quarkonium potential at nonzero temperature in instanton liquid model

Distribution of direct instanton contribution to the static heavy quarks potential at nonzero temperature in the instanton liquid model with defining the expectation value of Wilson loop will be discussed. There will be given plot of the potential as a function of the distance between quarks in different temperatures.

Perturbative one gluon exchange potential with the consideration of the instanton interactions has form
$$V(r)=\lambda\cdot\bar{\lambda} g^2\int\frac{d^3k}{(2\pi)^3}\exp(i\vec{k}\vec{r})D_{44}(k)$$ where $$ D_{44}(k)=(\vec{k}^2+M_{g}(\vec{k},T)^2)^{-1}.$$ Considering the temperature dependence of dynamical gluon mass we calculate one gluon exchange potential and the results will be given as plots. As a conclusion there will be given temperature dependence of heavy quarks potential as a sum of static instanton contribution and one gluon exchange potentials $$V_{HQP}=V_{dir.inst.}+V_{one~gluon} $$

Speaker: Mr Nurmukhammad Rakhimov

Rakhimov N.pdf

12 Magnetic fields of relativistic magnetized compact stars in the braneworld

The exterior electromagnetic fields of slowly rotating relativistic magnetized star in the braneworld are studied in detail. The dependence of the electromagnetic energy losses of the rotating magnetized star from the brane tension is also calculated and has been combined with the astrophysical data on pulsar period slow down in order to get constraints on the brane parameter. We have found the upper limit for the brane parameter as $Q ≲ 3\times 10^{11}$cm$^2$.

Speaker: Mr Abdullo Hakimov (Ulugh Beg Astronomical Institute of the Uzbek Academy of Scienses)

Hakimov_WorkShop.pdf

13 Can a test magnetic field serve as a cosmic censor?

Einstein gravity pronounced that black hole can be formed as a consequence of gravitational collapse, and Penrose later proposed in 1969 that a singularity would always be hidden behind a horizon. This is what is called Cosmic Censorship Conjecture (CCC). There exists no proof of the conjecture that it has remained unproven yet in either way, true or false. Thus, the physical possibility of destroying a near-extremal black hole due to over-spinning/over-charging process could be valid. The magnetic field, although small, affects the motion of charged particles drastically due to the large Lorentz force, as the electromagnetic force is much stronger than the gravity. We will focus here on the aspect of destroying horizon of a near extremal black hole in testing CCC. Then, the effect of the test magnetic field can be tested as an alternative tool to restore the CCC. We show that a test magnetic field would act as a cosmic censor beyond a certain threshold value.

Speaker: Mr Sanjar Shaymatov (Ulugh Beg Astronomical Institute)

shaymatov_NUUz_2018.pdf

14 Plasma magnetosphere of slowly rotating magnetized neutron star in braneworld

Plasma magnetosphere surrounding rotating magnetized neutron star in the braneworld has been studied. Goldreich-Julian charge density in plasma magnetosphere is analyzed for the misaligned neutron star with two different values of the inclination angle ($\chi=0$ and $\chi=\pi/2$) between magnetic field and rotation axis.The system of Maxwell equations in spacetime of slowly rotating star in braneworld is converted into second-order differential equation for electrostatic potential. Analytical solution of this equation indicates the braneworld modification of an accelerating electric field and charge density along the open field lines by brane tension. The implication of this effect to the magnetospheric energy loss problem is underlined. It was found that for initially zero potential and field on the surface of a neutron star, the amplitude of the plasma mode created by Goldreich-Julian charge density will increase in the presence of the negative brane charge. Finally we derive the equations of motion of test particles in magnetosphere of slowly rotating star in the braneworld. Then we analyze particle motion in the polar cap and show that brane tension can significantly change conditions for particle acceleration in the polar cap region of the neutron star.

Speaker: Mr Rayimbaev Javlon ( Ulugh Beg Astronomical Institute)

Rayimbaev2.11.2018.pdf

Wednesday, 7 November

Nuclear Astrophysics I

15 Allowed Gamow-Teller (GT) strengths and $\beta^+$ decay rates for Odd-A nuclei

In a recent study by Cole et al. [A. L. Cole et al., Phys. Rev. C 86 (2012) 015809], it was concluded that quasi-particle random phase approximation (QRPA) calculations show larger deviations and overestimate the total experimental Gamow–Teller (GT) strength. It was also concluded that QRPA calculated electron capture rates exhibit larger deviation than those derived from the measured GT strength distributions. The main purpose of this study is to probe the findings of the Cole et al. paper. This study gives useful information on the performance of QRPA-based nuclear models. As per simulation consequences, the electron capture (EC) rates on medium-heavy nuclei have a key impact on decreasing the ratio of electron-to-baryon of the stellar matter during the late stages of stars formation. Stellar model mostly rely on EC rates tables, based on the theoretical approaches, which should be tested against the available measured data.
In this work we present the computation of allowed charge-changing transitions for odd-A ($^{45}$Sc and ${}^{55}$Mn) fp-shell nuclei by using the deformed pn-QRPA models. The GT transition strength is compared with theoretical (including shell and other QRPA models) and measured charge-changing reaction results. For stellar applications the corresponding electron captures (EC) rates are computed and compared with previous theoretical and measured results. It was observed that our results are in good accordance with measured data. At higher stellar temperature calculated EC rates by pn-QRPA are higher than the independent particle model and shell model rates. It was further concluded that at low temperature and high density region the positron emission rates can be neglected.

Speaker: Prof. Jameel-Un Nabi (GIK Institute)

odd A Russia conf.pptx

16 Asymptotic theory of charged-particle transfer reactions and nuclear astrophysics

In the present work, a new asymptotical theory is proposed for the peripheral sub- and above-barrier transfer $A(x,y)B$ reaction in the framework of a three-body model, where $x=y+a$, $B=A+a$ and $a$ is a transferred particle. The asymptotic theory is based on the idea of the fact that, firstly, a peripheral reaction is governed by the nearest to the physical region $(-1\le\cos\theta\le 1)$ singularity (ζ) of the reaction amplitude (θ is the scattering angle in the c.m.s.). Secondly, the dominant role played by the nearest singularity is the result of the surface nature of this reaction. The dominant contribution to the peripheral reaction comes from the surface and outer regions of nuclei corresponding to $R \le R_{ch}$, where $R$ and $R_{ch}$ are the relative distance between the center of mass of the colliding nuclei and the channel radius, respectively. The regions for the reaction amplitude decomposed on the partial waves ($l$), correspond to the several lowest partial waves with $l < kR_{ch}$ ( $l=0,1,2,$ and $k$ is a wave number of the colliding nuclei) for sub-barrier energies $(k= (2\mu E)^{1/2}/\hbar \rightarrow 0$, $E\rightarrow 0$ and $\mu$ is the reduced mass of the colliding nuclei) and to the peripheral partial waves with $l\ge kR_{ch}>>1$ for the above-barrier energies ($E =10 -15 {\rm MeV}/N$).
In the proposed asymptotic theory, the main advantage of the dispersion method and the distorted wave Born approximation (DWBA) are combined. There the allowance of the contribution of the three-body ($A$, $y$ and $a$) Coulomb dynamics of the transfer mechanism to the peripheral partial amplitudes, which is determined by the nearest singularity of the reaction amplitude located at $\cos\theta = \zeta$, is done properly.
The explicit form of the differential cross section for the reaction under consideration is derived. This form is expressed in terms of the product of the squared asymptotic normalization coefficients (ANCs) for $y+a x$ and $A+a B$. The ANCs determine the amplitude of the tail of the radial overlap functions for the bound state wave functions of the x and B nuclei in the $(y+a)$ and $(A+a)$ channels, respectively. The asymptotic theory is applied for the analysis of the experimental differential cross sections (DCSs) both of the sub-barrier $^{19}$F($p,\alpha){}^{16}$O reaction and of the above-barrier $^{16}$O(${}^3$He, d)${}^{17}$F, ${}^9$Be(${}^{10}$B, ${}^9$Be)${}^{10}$B and ${}^{11}$B(${}^{12}$C, ${}^{11}$B)${}^{12}$C reactions measured by other authors.
As a result, the values of the squared ANCs for ${}^{16}$O+$t\rightarrow{}^{19}$F, ${}^{16}$O$+p\rightarrow{}^{17}$F,${}^9$Be$+p\rightarrow{}^{10}$B and ${}^{11}$B+$p\rightarrow{}^{12}$C are determined. They are to be equal 583.346.1, 1.350.14, 6216632, 4.350.19 and 311.613.3 fm$^{-1}$ for ${}^{16}$O $+t\rightarrow{}^{19}$F, ${}^{16}$O$ +p\rightarrow{}^{17}$F(g.s), ${}^{16}$O $\rightarrow{}^{17}$F(0.429 MeV), ${}^9$Be$ +p\rightarrow{}^{10}$B and ${}^{11}$B$ +p\rightarrow{}^{12}$C, respectively.
The ANC values for ${}^{16}$O$ +t\rightarrow{}^{19}$F, ${}^{16}$O$ +p\rightarrow{}^{17}$F and ${}^9$Be$ +p \rightarrow{}^{10}$B are used for the estimation of cross section of the nuclear-astrophysical ${}^19$F$(p,\alpha){}^{16}$O reaction at sub-barrier projectile energies 250, 350 and 450 keV. They also used for the estimation of astrophysical S factors corresponding to the nuclear-astrophysical ${}^{16}$O$(p,\gamma){}^{17}$F and
${}^9$Be$(p,\gamma){}^{10}$B reactions at zero energy. The obtained results are compared with those from other authors.
This work has been supported in part by the Ministry of Innovations and Technologies of the Republic of Uzbekistan (grant No. HE F2-14) and by the Ministry of Education and Science of the Republic of Kazakhstan (grant No AP05132062).

Speaker: Prof. Rakhim Yarmukhamedov (Institute of Nuclear Physics, Academy of Sciences of Uzbekistan)

asym-theory-report Yarmkh - final.pdf

Coffee break

Nuclear Astrophysics II

17 Nuclear astrophysics and resonant reactions: exploring the threshold region with the Trojan Horse Method

Resonant reactions play an important role in astrophysics as they might significantly enhance the cross section with respect to the direct reaction contribution and alter the nucleosynthetic flow. Moreover, resonances bear information about states in the intermediate compound nucleus formed in the reaction. However, nuclear reactions in stars take place at energies well below ∼1 MeV and the Coulomb barrier, exponentially suppressing the cross section, and the electron screening effect, due to the shielding of nuclear charges by atomic electrons, make it very difficult to provide accurate input data for astrophysics.
Therefore, indirect methods have been introduced; in particular, the Trojan Horse Method (THM) (see Ref. [1] for a review of the method) makes use of quasi-free reactions with three particles in the exit channel, a + A → c + C + s, to deduce the cross section of the reaction of astrophysical interest, a + x → c + C, under the hypothesis that A shows a strong x + s cluster structure. In recent years, a generalized R-matrix approach has been introduced [2], allowing one to deduce the resonance parameters from the THM cross section accounting for half-off-energy-shell effects. In this way, THM can be used to perform a full spectroscopic study of low-energy and sub threshold resonances. For the latter, the ANC can be deduced as well, establishing an alternative high accuracy approach to determine this crucial parameter and leading to an unification of the two mentioned indirect methods.
In this presentation we will briefly discuss the theory behind the method, to make clear its do- main of applicability, the advantages and the drawbacks, and some experimental applications of this extended approach based on the generalised R-matrix [2]. Two recent cases will be shortly reviewed: the 19F(p,α)16O reaction, which is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars, and the 12C+12C reaction, which plays a critical role in astrophysics to understand stellar burning scenarios in carbon-rich environments.
19F(p,α)16O data stop at about 200 keV, making it necessary to extrapolate its trend at lower energies. The THM was thus used to access this energy region, by extracting the quasi-free contribution to the 2H(19F,α16O)n reaction. The THM measurement shows the presence of resonant structures not observed before, showing up right at astrophysical energies, which cause an increase of the reaction rate at typical stellar temperatures [3]. Recent direct measurements [4] reaching down to about 120 keV confirmed earlier THM predictions, validating such indirect approach.
Finally, the recent investigation of the 12C+12C fusion reactions will be presented [5]. The THM was applied to the 12C(14N,α20Ne)2H and 12C(14N,p23Na)2H three-body processes at 30 MeV of beam energy in the quasi-free kinematical regime, where 2H from the 14N Trojan Horse nucleus is spectator to the 12C+12C two-body processes. The 12C(12C, α)20Ne and 12C(12C,p)23Na cross sections at astrophysical energies were extracted, between 1 and 2 MeV center-of-mass energies, at odds with direct measurements stopping at 2.14 MeV, still at the beginning of the astrophysical region. A strong resonant behavior of the cross section associated to 24Mg levels was observed causing a strong enhancement of the reaction at the relevant temperatures [6].
[1] R.E. Tribble et al., Rep. Prog. Phys. 77 (2014) 106901.
[2] A.M. Mukhamedzhanov, Phys. Rev. C 84 (2011) 044616.
[3] M. La Cognata et al., Astrophys. J. 805 (2015) 128.
[4] M. La Cognata et al., Phys. Rev. Lett. 87 (2012) 232701.
[5] A. Cumming et al., Astrophys. J. 646 (2006) 429.
[6] A. Tumino et al., Nature 557 (2018) 687

Speaker: Dr Marco La Cognata (Laboratori Nazionali del Sud - Istituto Nazionale di Fisica Nucleare)

Tashkent-LaCognata.pptx

18 Probing the Early Universe through nuclear physics

Big Bang Nucleosynthesis (BBN) requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of d(d,p)t, d(d,n)3He and 3He(d,p)4He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM) to study reactions of relevance for the BBN and measure their astrophysical S(E)-factor. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01<T9 <10). These value were then used as input physics for primordial nucleosynthesis calculations in order to evaluate their impact on the calculated primordial abundances and isotopical composition for H, He and Li. New results on the 7Be(n,a)4He reaction rate were also taken into account.These were compared with the observational primordial abundance estimates in different astrophysical sites. Reactions to be studied in perspective will also be discussed

Speaker: Dr Rosario Pizzone (Dr.)

Pizzone.pptx

Lunch

Nuclear Astrophysics III

19 THM implication for stellar nucleosynthesis: a couple of examples

In recent years, the Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of several reactions of interest for Astrophysics. We present two cases in which the application of THM reaction rates has modified the prediction of stellar nucleosynthesis. In the first case, the determination of the strengths of the 20 keV and 65 keV resonances in the $^{18}$O(p,α)$^{15}$N and $^{17}$O(p,α)$^{15}$N reactions, respectively, allows to state that the oxygen isotopic mix found in some pristine meteorites is the signature of low-temperature proton-capture nucleosynthesis typical of evolved low mass stars. In the second case the studies of the $^{19}$F(p,α)$^{16}$O and $^{19}$F(α,p)$^{16}$O reactions via the Trojan Horse Method hint to an enhancements in efficiency of fluorine destruction by H and He-burning of AGB stars, which are considered the main source of fluorine in galaxies.

Speaker: Dr Sara Palmerini (INFN Perugia)

PALMERINI-UZ.pdf

20 Indirect methods in nuclear astrophysics with radioactive ion beams

Speaker: Prof. Silvio Cherubini (Catania University & INFN-LNS, Italy)

21 Theoretical study of the direct alpha+d → 6Li +gamma astrophysical capture process in a three-body model: Astrophysical S-factor, reaction rates and primordial abundance

The astrophysical S-factor and reaction rate of the direct capture process $\alpha+d \rightarrow {}^6{\rm Li} + \gamma$, as well as the abundance of the 6Li element are estimated in a three-body model. The initial state is factorized into the deuteron bound state and the $\alpha+d$ scattering state. The final nucleus $^6$Li(1+) is described as a three-body bound state $\alpha+ n + p$ in the hyperspherical Lagrange-mesh method. Corrections to the asymptotics of the overlap integral in the $S$- and $D$-waves have been done for the E2 S factor. The isospin forbidden $E1$ S-factor is calculated from the initial isosinglet states to the small isotriplet components of the final $^6$Li(1+) bound state. It is shown that the three-body model is able to reproduce the newest experimental data of the LUNA collaboration for the astrophysical S-factor and the reaction rates within the experimental error bars. The estimated $^6$Li/H abundance ratio of (0.67 ± 0.01) × 10−14 is in a very good agreement with the recent measurement (0.80 ± 0.18) × 10−14 of the LUNA collaboration.

Speaker: Dr Ergash Tursunov (Institute of Nuclear Physics, AS RUz)

WORKSHOP_2018_Tursunov.ppt

Coffee break

Student Session II

22 Determination of the asymptotic normalization coefficient (nuclear vertex constant) for $\alpha+d\rightarrow {}^6{\rm Li}$ from the new direct measured $d(\alpha,\gamma){}^6{\rm Li}$ data and its implication for extrapolating the $d(\alpha,\gamma){}^6{\rm Li}$ astrophysical $S$ factor at extremely low energies

In the present work, the results of the analysis of the experimental astrophysical $S$ factors (AS) $S^{\exp}(E)$ [1,2] for the nuclear-astrophysical $d(\alpha,\gamma){}^6{\rm Li}$ reaction directly measured at extremely low energies E are presented. One notes that the $d(\alpha,\gamma){}^6{\rm Li}$ reaction is of great interest as one of the sources of the 6Li creation in the early Universe [1].
The analysis is performed within the modified two-body potential method [3]. The method involves two additional conditions that verify the peripheral character of the direct radiative capture reaction $d(\alpha,\gamma){}^6{\rm Li}$: 1) $R(E,b)= const$ for arbitrary variation of the free model parameter b for each fixed experimental value of the energy $E$; 2) the ratio $C_d^2 = S^{\exp}(E)/R(E,b)$ must not depend neither from b and nor from the energy E for each experimental point $ E=E_i$, where $R(E,b)=S^{(sp)}(E;b)/b^2$ and $i=1,2,…N (N =4)$ is a number of experimental points for $S^{\exp}(E_i)$. Here $S^{(sp)}(E;b)$ is a single-particle astrophysical $S$ factor and $b$ is the amplitude of the tail of the radial $s$-component wave function of the bound ${}^6Li (=\alpha+d)$ state, which is calculated in the framework of the shell model using the phenomenological Woods-Saxon potential with the geometric parameters (a radius $r_o$ and a diffuseness a). The value of $b$ strongly changes as a function $(r_o, a)$-pair, i.e., $b= b (r_o, a)$. Fulfilment of the conditions, firstly, it makes it possible to remove the model dependence of the calculated direct $S(E)$ on the geometric parameters $r_o$, and a both for the two-body bound $(\alpha + d)$ state and the $d$-scattering one in minimum being within the experimental errors. It allows, secondly, us to determine “experimental” value of $C_d^2 [=(C_d^{\exp})^2]$ and its uncertainty by model-independent way. The obtained $(C_d^{exp})^2$ values can be implemented in the expression $S(E)= (C_d^{\exp})^2 R(E,b)$ for obtaining the extrapolated values of S(E) and its uncertainties within the energy range $E< E_1$, including $E=0$.
Variation of values of the parameters ro, and a is done in the wide range (1.13≤ r0 ≤1.37 fm, 0.58≤ a ≤0.72 fm, 2.37≤b≤ 2.86 fm$^{-1/2}$ ) and is shown that the reaction is strongly peripheral. As a result, the ANC $(C_d^{exp})^2$, NVC $|C_d^{exp}|^2$ and $S(0)$ values were obtained. They are equal to $(C_d^{exp})^2 = 5.33\pm 0.35 {\rm fm}^{-1}$, $|C_d^{\exp}|^2 =0.43\pm 0.03$ fm and $S(0)= 1.32\pm 0.09$ MeV·nb, which can be considered as determined from the direct measured data of the $S^{\exp}(E)$ for the first time. The obtained results are compared with those from other authors.
This work has been supported in part by the Ministry of Innovations and Technologies of the Republic of Uzbekistan (grant No. HE F2-14).

1. R. Robertson, P. Dyer, R. Warner et al. Phys. Rev. Lett. 47 (1981) 1867.
2. D. Trezzi, M. Anders, M. Aliotta, et al. Astro. Phys. 89 (2017)57.
3. S. B. Igamov, R. Yarmukhamedov. Nucl. Phys. A 781 (2007) 247.

Speaker: Mr K. Tursunmakhatov (Institute of Nuclear Physics, Academy of Sciences of Uzbekistan)

K.Tursunmaxatov.pptx

23 The role of the N/Z-ratio in colliding nuclei during the fusion of sulfur and lead

One of the most interesting problems in heavy-ion physics is an identification of the reactions which are called deep-inelastic collisions, quasifission and fusion-fission. These reactions are called binary reactions and their mechanisms are in competition to synthesis of superheavy elements in the different stages of formation of evaporation residue which is considered as a superheavy element. The products of the binary reactions are characterized by the angular, mass (charge) and energy distributions. The mass distribution of quasifission products can overlap with the products of deep-inelastic collisions but the difference between their angular and energy distributions allow us to separate them at analysis of the experimental data.

By using dinuclear system (DNS) model the capture and fusion cross sections are calculated for the reactions $^{34}$S+$^{208}$Pb and $^{36}$S+$^{206}$Pb which are leading same compound nucleus (CN) $^{242}$Cf. The characteristics of the reaction products and cross sections are determined by the properties of the intermediate DNS formed at the capture stage of the projectile nucleus by the target nucleus. The behavior of the DNS depends on the initial beam energy, angular momentum and properties of the interacting nuclei such as shape and shell effects.

The difference between fusion cross sections at the energy near to Coulomb barrier is studied to explain the phenomenon observed in the JAEA [1]. The results show that at the energy near to Coulomb barrier the capture occurs for the wide range of angular momentum in the reaction $^{36}$S+$^{206}$Pb comparing to the $^{34}$S+$^{208}$Pb. However, the difference between observed cross sections of the evaporation residues of the $^{34}$S+$^{208}$Pb and $^{36}$S+$^{206}$Pb reactions formed in the 2n and 3n channels has been explained by the effect of the $N/Z$-ratio in colliding nuclei at formation of the DNS during the capture and its transformation into a compound nucleus.

1. J. Khuyagbaatar, et al., Phys.Rev. C 86, 064602 (2012)

Speaker: Mr Bakhodir Kayumov (INP AS RUz)

Kayumov.pdf

24 $^3$He(α, γ)$^7$Be and $^3$H(α, γ)$^7$Li reaction rates and its implications for Big Bang nucleosynthesis

The astrophysical S-factor and reaction rates of the direct capture processes $^3$He(α, γ)$^7$Be and $^3$H(α, γ)$^7$Li, as well as the abundance of the $^7$Li/H element are studied in the framework of the two-body model with potentials of a simple Gaussian form, which describe correctly the phase shifts in the s, p, d, and f waves, as well as the binding energy and the asymptotic normalization constant of the ground p3/2 and the first excited p1/2 bound states. It is shown that the E1 transition from the initial s wave to the final p waves is strongly dominant in both capture reactions. On this basis the s-wave potential parameters are adjusted to reproduce the new data of the LUNA Collaboration around 100 keV and the newest data at the Gamov peak estimated with the help of the observed neutrino fluxes from the sun, S34(23+6−5 keV) = 0.548 ± 0.054 keVb for the astrophysical S factor of the capture process $^3$He(α,γ )$^7$Be. The resulting model describes well the astrophysical S factor in the low-energy big-bang nucleosynthesis region of 180–400 keV; however, it has a tendency to underestimate the data above 0.5 MeV. The energy dependence of the S factor is mostly consistent with the data and the results of the no-core shell model with continuum, but substantially different from the fermionic molecular dynamics model predictions. Two-body potentials, adjusted for the properties of the 7Be nucleus, $^3$He + α elastic scattering data, and the astrophysical S factor of the $^3$He(α, γ)$^7$Be direct capture reaction, are able to reproduce the properties of the 7Li nucleus, the binding energies of the ground 3/2− and first excited 1/2− states, and phase shifts of the 3H + α elastic scattering in partial waves. Most importantly, these potential models can successfully describe both absolute value and energy dependence of the existing experimental data for the mirror astrophysical $^3$H(α, γ)$^7$Li capture reaction without any additional adjustment of the parameters. Finally, the estimated $^7$Li/H abundance ratio of (5.08±0.13) x 10-10 is in a very good agreement with the recent measurement (5.0 ± 0.3) × 10−10 of the LUNA collaboration.

Speaker: Mr Sobir Turakulov (Institute of Nuclear Physics, Academy of Sciences RUz)

S.Turakulov.pptx

25 Collision centrality dependencies of charged pion production in 12C+181Ta collisions at 4.2 A GeV/c

Speaker: Ms Shakhnoza Kanakova (National University of Uzbekistan)

СС ready.pptx

26 Modified activation method for measurement of the yield of astrophysical reactions

Speaker: Mr Olimjon Tojiboyev (Institute of Nuclear Physics, Academy of Sciences RUz)

presentation-Tojiboyev.pdf

Banquet

Friday, 9 November

Nuclear matter and Nuclei

27 Nuclear Halos and Efimov Effect: A three-body approach

The advent of Radioactive Ion Beam facilities and subsequent explosive growth in the studies of neutron rich nuclei near the drip line have opened up new vistas in modern nuclear physics. The discovery of halo structures, both 1-neutron and 2-neutron halos, in neutron-rich, light nuclei has been a significant development in nuclear structure studies. The 2-neutron halo nuclei can have both Borromean or non-Borromean properties and can be ideally modeled as three-body systems. A variety of theoretical techniques have been applied over the years to investigate the structural properties of 2-neutron halo nuclei. Of all these techniques, three-body approaches appear to be very successful and effective. In this talk we will summarise our efforts, over the years, to calculate different structural properties of 2-n halo nuclei, like, $^{11}$Li, $^{14}$Be, $^{20}$C etc. We will also talk about our search for the elusive Efimov effect in such nuclei. We will show the possible presence of Efimov states in certain non-Borromean 2n halo nuclei, their evolution to resonances with increasing neutron-core ( 2-body) interaction and emergence as an asymmetric Fano resonance.

Speaker: Prof. Indranil Mazumdar (Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research)

TashkentTalk_Indranil.ppt

28 Various aspects of nuclear matter studied with direct reactions

Speaker: Prof. Tomohiro Uesaka (RIKEN, Japan)

Coffee break

Nuclear matter and Nuclei

29 From Nucleons to Nuclei (chiral soliton approach)

We discuss "the modelling of nuclear physics" in the framework of in-medium modified chiral soliton model. We discuss the hadron structure changes in nuclear matter, Equations of State of symmetric and asymmetric nuclear matter, properties of neutron stars and finite nuclei properties at same footing, starting from the same Lagrangian.

Speaker: Prof. Ulugbek Yakhshiev (Inha University )

Lunch

Neutron stars, black holes, gravitational waves

30 Impact of Neutron Star Merger and Supernova Nucleosynthesis on Gravitational Wave, Element Genesis and Neutrino Physics

GW170817/SSS17a was an event of the century that opened a new window to multi-messenger astronomy and nuclear astrophysics. Optical and near-infrared emissions among many other observables suggest that their total energy release is consistent with radiative decays of r-process nuclei predicted theoretically although no specific r-process element was identified. Core-collapse supernovae (both MHD Jet-SNe and ν-SNe) are viable candidates for the r-process. MHD Jet-SNe explain the “universality” in the observed elemental r-process abundance pattern in metal poor stars. Neutron star merger (NSM), on the other hand, could not contribute to the early Galaxy for cosmologically long merging time-scale for slow GW radiation. Nevertheless, NSM is still a possible explanation for the solar-system r-process abundance. We propose a novel solution to this twisted problem by carrying out NSM and SN r-process nucleosynthesis calculations with Galactic chemo-dynamical evolution [1-4].
We also discuss the impact of SN nucleosynthesis on the physics of neutrino oscillations. The elements at A = 80-100 originate from many processes such as r-, s-, rp-, γ-, ν-, νp-processes [5,6]. We find that νp-process operates strongly with amounts of free neutrons being supplied even on proton-rich (Ye > 0.5) condition via p(ν, e+)n reactions when one takes account of the effects of collective neutrino oscillations [7]. Reaction flows can reach the production of abundant p-nuclei 94Mo, 96Ru, etc. This nucleosynthetic method turns out to be a unique probe indicating still unknown neutrino-mass hierarchy.
[1] S. Shibagaki, T. Kajino, G. J. Mathews et al., ApJ 816 (2016), 79.
[2] T. Kajino & G. J. Mathews, Rep. Prog. Phys. 80 (2017), 084901.
[3] Y. Hirai, T. Kajino et al., ApJ 814 (2015), 41; MNRAS 466 (2017), 2472-2487.
[4] T. Kajino et al., Prog. Part. Nucl. Phys. (2018), in press.
[5] T. Kajino, G. J. Mathews & T. Hayakawa, J. Phys. G41 (2014), 044007.
[6] T. Hayakawa, T. Kajino et al., Phys. Rev. Lett. 121 (2018), 102701.
[7] H. Sasaki, T. Kajino, T. Takiwaki et al., Phys. Rev. D96 (2017), 043013.

Speaker: Prof. Taka Kajino (Beihang University & The University of Tokyo)

31 Energetic and Optical Properties of Gravitational Compact Objects

End state of evolution of isolated and binary massive stars/black holes including various observational astrophysical properties of magnetized neutron stars and black holes are discussed. The energetics of rotating black holes and neutron stars is also analyzed. The possibilities of probing black holes nature through the study of their optical properties areexplored in detail.

Study the photons motion around rotating black holes, in particular, the discovery and analysis of the form of silhouettes of these objects, setting and effective implementation of relevant radiostronomical observations on the proof of the existence of the black hole horizon and retrieval of information events on the central object in our galaxy within the Black Hole Cam (BHC) and Event Horizon Telesop (EHT) international projects is one of the most important tasks of modern astrophysics. A general formalism to describe the black hole shadow as an arbitrary polar curve expressed in terms of a Legendre expansion is applied to the specific black holes. The developed formalism offers a number of routes to characterize the distortions of the curve boundaring shadow with respect to reference circles. These distortions are implemented in a coordinate independent manner by different teams analyzing the same data. It has been shown that the new formalism provides an accurate and robust description of noisy observational data, with smaller error variances when compared to previous measurements of the distortion.

Speaker: Prof. Bobomurat Ahmedov (Ulugh Beg Astronomical Institute, Astronomicheskaya 33, Tashkent 100052, Uzbekistan and National University of Uzbekistan, Tashkent 100174, Uzbekistan)

ahmedov_NUUz-talk-2018.pdf

Coffee break

Nuclear reactions

32 Fragmentation of 1.2A GeV/C $^{10}$C in nuclear emulsion

It is discussed the experimental results and their comparison with multi-source thermal model calculations by fragmentation of isotope $^{10}$C to much lighter nuclear such as $^8$Be, $^4$He and etc. Conclusions obtained basing on investigation and angle distribution analysis fragments relative direction projectile particles and also spectrum of distribution on transverse momentum of fragments from $^{10}$C allows possibility of using multi-source thermal model at energy of interactions 1.2 A GeV.

Speaker: Prof. Rahmatullo Bekmirzaev (Jizzax State Pedagogical Institute)

fragmenttezis1.doc

33 Three-nucleon force effects on the proton elastic scattering with 10C

Speaker: Dr Alisher Sanetullaev (Inha University in Tashkent)

Alisher_NATHANP2018.pdf

34 Singular structure of the QED effective action

The equations for the QED effective action derived in [3] are considered using
singular perturbation theory. The effective action is divided into regular and singular
(in coupling constant) parts. It is shown that expression for the regular part coincides
with usual Feynman perturbation series over coupling constant, while the remainder
has essential singularity at the vanishing coupling constant: e → 0. This means that
in the frame of quantum field theory it is impossible ”to switch off” electromagnetic
interaction in general and pass on to ”free electron”.

Speaker: Prof. Biruniy Fayzullaev (National University of Uzbekistan)

singQED_NUUZ_Conf_18.pdf

Preliminary remarks

Saturday, 10 November

100 years of NUU

35 Application of the theory of open quantum systems to nuclear physics problems

Speaker: Prof. Zakirjan Kanakov (National University of Uzbekistan)

Workshop2018.pdf

36 Phenomenological analysis of properties rotational states of collective excitation isotopes

Speaker: Prof. Pazliddin Uzmanov (Namangan Engineering-Technology Institute)

Final remarks