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7/16/2018 IWND2018 1 International Workshop on Nuclear Dynamics IWND2018 Hozhou, China, June 10-14, 2018 THANNAMANDI , JAMMU & KASHMIR, INDIA

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Page 1: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 1

International Workshop on Nuclear Dynamics IWND2018

Hozhou, China, June 10-14, 2018

THANNAMANDI , JAMMU & KASHMIR, INDIA

Page 2: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 2

[email protected]

Symmetric and asymmetric fragmentation reactions at intermediate energy heavy-ion collisions using isospin-

dependent quantum molecular dynamics model

International Workshop on Nuclear Dynamics IWND2018

Hozhou, China, June 10-14, 2018

Arun Sharma

(In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India)

Department of Physics, Govt. Degree College Thannamandi, J&K, India

By

Page 3: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 3

Points to discuss

Dynamics of nearly symmetric and asymmetric nuclear reactions.

Confrontation of Isospin-dependent quantum molecular dynamics model results with measurements as well as with other available calculated results using different models. Isospin Effects via Coulomb forces and momentum-dependent interactions on the onset of multifragmentation.

Page 4: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 4

Symmetric Nuclear Reactions

Asymmetric Nuclear Reactions

Significant Share of Excitation

energy is stored in the form of

compressional energy

Significant Share of Excitation

energy is stored in the form of

thermal energy

Asymmetric nuclear matter has gained interest because the dynamics of asymmetric collisions is different from that of symmetric reactions

“η” is the mass asymmetry (= [AT -AP ] / [AT +AP]; AT /AP are the masses of the target/projectile)

Page 5: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 5

M O T I V A T I O N

QMD type models face problems to handle dynamics of asymmetric reactions but they work well for symmetric reactions.

Page 6: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 6

Isospin-Dependent Quantum Molecular Dynamics (IQMD) Model

• Initialization: Generate the Projectile/Target (P/T).

• Propagation: Nucleons of P/T propagate under the

influence of mean field.

• Nucleon-Nucleon (nn) Collisions: Nucleons scatter

if they come too close.

Ch. Hartnack, Rajeev K. Puri, J. Aichelin, J. Konopka, S.A. Bass, H. StÄocker, W. Greiner2, EPJA 1, 151 (1998).

Page 7: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

PRINCIPLE: RUNS

INITIALIZATION

COLLISION PART

PROPAGATION PART

i

i

i

i

H

td

d

H

td

d

r

p

p

r

∑ t

10,000-10,00,000

Store at 0.1 fm/c time difference from initial to final time

7/16/2018 7 IWND2018

Page 8: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

pdpdrdrdtprfrrVtprfm

pj

i ij

ij

i

ii

i

),,(),(),,(2

2

C. Hartnack et al., Eur. Phys. J A 1, 151 (1998).

Propagation

ij

sym

ij

MDI

ij

Coul

ij

Yukawa

ij

Skyrme

ijVVVVVrrV ),(

VTH P.E. K.E.

,r

Hp;

p

Hr

i

i

.

i

i

.

7/16/2018 8 IWND2018

Page 9: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 9

0 3 6 9 12 1510

1

103

105

107

109

1011

1013

1015

1017

1019

1021

1023

1025

1027

Present

Data

30 MeV

(x 106 )

25 MeV

(x 104 )

115 MeV

(x 1022

)

105 MeV

(x 1020

)

95 MeV

(x 1018

)

45 MeV

(x 1010

)

65 MeV

(x 1012

)

75 MeV

(x 1014

)

85 MeV

(x 1016

)

35 MeV

(x 108 )

20 MeV

(x 102 )

dN

/dZ

f (m

b)

40

18Ar+

45

21Sc

Zf

E / A

15 MeV

( x 100 )

Nearly symmetric reactions

The Charge distributions become steeper with increase in beam energy reflecting the violence of collisions. This behavior is opposite to that with increase of impact parameter

The charge distributions are fitted with power law

∝ Z -ɽ from 3≤Z≤12

T. Li et al., Phys. Rev. C 49, 1630 (1994). (source of data)

Page 10: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 10

0 25 50 75 100 1250

1

2

3

4

5

6

Present

Data

40

18Ar+

45

21Sc

Energy (MeV/nucleon)

Ç

The extracted parameter “ɽ” is plotted against the incident energy and rather than sharp minima flatness behavior is observed at low energies.

Our calculations reproduces the experimental extracted “ɽ” values.

Page 11: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 11

0 10 20 30 40 50 60 70 8010

-5

10-3

10-1

101

103

IQ1

IQ2

IQ3

Present

Data

32 MeV/nucleon

129

54Xe+

120

50Sn

d

N/d

Zf

(a)

}ImQMD

0 10 20 30 40 50 6010

-5

10-3

10-1

101

103

39 MeV/nucleon

(b)

Zf

0 10 20 30 40 50 6010

-5

10-3

10-1

101

103

(c)45 MeV/nucleon

0 5 10 15 20 25 3010

-3

10-2

10-1

100

101

102

Present

AMD/DS

AMD/D

Data 50 MeV/nucleon

Zf

dN

/dZ

f129

54Xe+

120

50Sn

The results of ImQMD model have been shown for three sets of equation of state [labeled as IQ1, IQ2 and IQ3]

AMD model calculations are truncated at finite time (of 300 fm/c) and decay of excited fragments is done by statistical decay code.

Prog. Part. Nucl. Phys. 53, 501 (2004) ,Source of data

Phys. Rev. C 87, 066615 (2013) & Chin. Phys. C 37, 114101 (2013), Source of data

Page 12: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 12

10-3

10-2

10-1

100

101

dN/d

Zf

(a)

84

36Kr+

197

79Au

35 MeV/nucleon

Zf

55 MeV/nucleon(b)

70 MeV/nucleon(c)

0 3 6 9 1210

-3

10-2

10-1

100

100 MeV/nucleon(d)

0 3 6 9 12

200 MeV/nucleon(e)

0 3 6 9 12

400 MeV/nucleon(f)

Present

Data

0

4

8

12

(c)

(b)

(a) QMD (unfiltered)

QMD (filtered)

QMD+SMM (unfiltered)

QMD+SMM (filtered)

Data

Present

0

4

8

12

(III)

(II)

(I)

Present (IICS+RFM)

Present (WSP)

Present (RFM)

IIIII

I

30 60 100 200 4000

50

100

150

84

36Kr+

197

79Au

Present

Present (RFM)

Energy (MeV/nucleon)

<N

C>

<N

IMF

s>

<

NIM

Fs> IQMD overcomes the apprehension at low

incident energies.

INVESTIGATION OF DIFFERENT RESULTS USING QMD AND IQMD

MODELS

Phys. Rev. C 55, R2132 (1997) & Phys. Rev. C 49, R2271 (1994)

Page 13: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 13

10-4

10-3

10-2

10-1

100

101

102

Present

FREESCO-I

FREESCO-II

Copenhagen

Data

25 MeV/nucleon

50 MeV/nucleon16

8O+

80

35Br

dN

/dZ

f

(a) (b)

10-4

10-3

10-2

10-1

100

101

(c)

75 MeV/nucleon

Zf

(d)

150 MeV/nucleon

0 10 20 3010

-4

10-3

10-2

10-1

100

101

(e)

100 MeV/nucleon

0 10 20 30 40

(f)

200 MeV/nucleon

10-4

10-3

10-2

10-1

100

101

102

(b)(a)

dN/d

Zf

Present

FREESCO-I

FREESCO-II

Copenhagen

QMD

Data

25 MeV/nucleon

16

8O+

108

47Ag

100 MeV/nucleon

10-4

10-3

10-2

10-1

100

101

(c)

50 MeV/nucleon

Zf

(d)

150 MeV/nucleon

0 10 20 30 4010

-4

10-3

10-2

10-1

100

101

(e)

75 MeV/nucleon

0 10 20 30 40 50

(f)

200 MeV/nucleon

Calculations also include results of two statistical models i.e, FREESCO and Copenhagen, which describe the breakup of excited nuclear matter and a dynamical approach namely, quantum molecular dynamics (QMD) model.

Nu

cl. Ph

ys. A 5

09

, 19

5 (1

99

0) d

ata Sou

rce

Page 14: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 14

10-4

10-3

10-2

10-1

100

Present

Data

16

8O+

80

35Br

200 MeV/nucleon

dN

/dZ

f

(a)

0 5 10 15 20 25 30 3510

-4

10-3

10-2

10-1

16

8O+

108

47Ag

(b)

Zf

10-4

10-3

10-2

10-1

100

101

102

Present

GEMINI

Data

25 MeV/nucleon

197

79Au+

12

6C

25 MeV/nucleon

dN

/dZ

f

(a)

10-4

10-3

10-2

10-1

100

101

102

(b)

SMM

197

79Au+

64

29Cu

35 MeV/nucleon

0 10 20 30 40 50 60 70 8010

-4

10-3

10-2

10-1

100

101

102

197

79Au+

64

29Cu(c)

Zf

Semi-cental colliding geometry leads to less violent collisions and extended tail towards higher Zf when compared with most central collisions

Extended charge distribution tail

Nucl. Phys. A 724, 455 (2003)

Page 15: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 15

0 5 10 15 2010

-3

10-2

10-1

100

101

102

Present

Percolation (unfiltered)

Percolation (filtered)

Data

50 MeV/nucleon

36

18Ar+

197

79Au

0 5 10 15 20 25

80 MeV/nucleon

36

18Ar+

197

79Au

0 5 10 15 2010

-3

10-2

10-1

100

101

102

(c)

110 MeV/nucleon

36

18Ar+

197

79Au

Zf

0 5 10 15 20 25

(d)

(b)

50 MeV/nucleon

129

54Xe+

79,197Au

dN

/dZ

f

(a)

0

40

80

120

160

200(a)

<N

IMF

s><

NL

CP

s>

40

18Ar+

64

29Cu

<A

max

f>

(b) 40

18Ar+

108

47Ag

(c) 40

18Ar+

197

79Au

Energy (MeV/nucleon)

0

10

20

30

(d)

Present

SMM

Berlin

Evap.

Data

(e)

(f)

0 30 60 90 1200

3

6

9

12(g)

Present

0 30 60 90 120

(h)

0 30 60 90 120

(i)

SOME MORE CALCULATIONS

COVERING GOOD RANGE OF ASYMMETRY PARAMETER

R. Sun et al., Phys. Rev. C 61, 061601 (R) (2000).

Page 16: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 16

Results are published in the international Journal of Nuclear Physics A

Multifragmentation of nearly symmetric and asymmetric reactions within a dynamical model.

Arun Sharma et al.,

Nuclear Physics A 945, 95 (2016) (Elsevier-North Holland) [Impact factor- 1.98]

Page 17: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 17

A microscopic analysis of isospin effects on the onset of multifragmentation

in light and heavy charged systems via Coulomb forces

Page 18: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 18

M O T I V A T I O N

Critical energy point of the liquid-gas phase transition has been said to occur at intermediate energy and it may also be associated with the emission of fragments.

This critical energy point is related with the onset of Multifragmentation.

Page 19: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 19

The onset of multifragmentation and its connection to the nuclear liquid-gas phase transition has been reported both experimentally and theoretically.

Also both Coulomb forces and momentum dependent interactions affect the multifragmentation phenomenon. Recent interest of the community has shifted to isospin physics. The basic cause of this shift is the availability of radioactive ion beams. Accordingly, most of the theoretical models have also been upgraded to include isospin degree of freedom.

We tried to probe the effect of Coulomb forces in the presence of momentum-dependent interactions on the onset of multifragmentation i.e., critical energy point in light and heavy colliding systems.

M O T I V A T I O N

Page 20: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 20

10-1

100

101

102

103

104

105

Soft

SMD

40

18Ar+

45

21Sc

E (MeV/nucleon) =

Coulomb On

15

(b)

20

(c)

25

dN

/dZ

f

(d)

30

Zf

10-1

100

101

102

103

104

(e)

35

(f)

45

(g)

65

(h)

75

0 5 1010

-1

100

101

102

103

104

(i)

85

0 5 10

(j)

95

(a)

0 5 10

(k)

105

0 5 10 15

(l)

115

Charge distributions become steeper with

increasing beam energy

Charge distributions for intermediate mass fragments are fitted

with power law

Onset of multifragmentation in light charged system

In the presence of Coulomb forces

Page 21: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 21

0 25 50 75 100 1250

1

2

3

4

5

6

7 Soft

SMD

40

18Ar+

45

21Sc

Energy (MeV/nucleon)

Coulomb OnValues of critical exponent for

both the equations of state increase with

incident energy

Critical exponent vs energy

Here, we do not observe any

minima in the extracted values of tau when plotted

against incident energy

Onset of multifragmentation may occur at lower incident energies

Page 22: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 22

Charge distributions are less steeper in

this case

10-1

100

101

102

103

104

105

Soft

SMD

40

18Ar+

45

21Sc

E (MeV/nucleon) =

Coulomb Off

15

(b)

20

(c)

25

dN

/dZ

f

(d)

30

Zf

10-1

100

101

102

103

104

(e)

35

(f)

45

(g)

65

(h)

75

0 5 1010

-1

100

101

102

103

104

(i)

85

0 5 10

(j)

95

(a)

0 5 10

(k)

105

0 5 10 15

(l)

115

In the absence of Coulomb forces

Coulomb forces can affect the

calculated charge distributions as well

as the onset of multifragmentation,

Page 23: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 23

0 25 50 75 100 1250

1

2

3

4

5

6

7

Soft

SMD

40

18Ar+

45

21Sc

Energy (MeV/nucleon)

Ç

Coulomb Off

Interestingly, the effect of Coulomb forces is visible

even for the light charged system

Solid arrow corresponds to the minimum in the

extracted tau values for soft equation of state

The steepening of charge distributions in the

absence of Coulomb forces gets slow down

Our calculations are consistent with T. Li et al., Phys. Rev. C 49, 1630

(1994).

Page 24: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 24

Accuracy of the critical energy point

10-1

100

101

102

103

104

105

Soft

SMD

40

18Ar+

45

21Sc

E (MeV/nucleon) =

Coulomb Off

15

(b)

20

(c)

25

dN

/dZ

f

(d)

30

Zf

10-1

100

101

102

103

104

(e)

35

(f)

45

(g)

65

(h)

75

0 5 1010

-1

100

101

102

103

104

(i)

85

0 5 10

(j)

95

(a)

0 5 10

(k)

105

0 5 10 15

(l)

115

0 25 50 75 100 1250.0

0.1

0.2

0.3

0.4Coulomb Off Soft 40

18Ar+

45

21Sc

Energy (MeV/nucleon)

Ç

Exponential fits are used to fit the intermediate mass

fragments

Page 25: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 25

Onset of multifragmentation in heavy charged system

10-3

10-2

10-1

100

101

dN/d

Zf

(a)

84

36Kr+

197

79Au

35 MeV/nucleon

Zf

55 MeV/nucleon

(b)

70 MeV/nucleon

(c)

0 3 6 9 1210

-3

10-2

10-1

100

100 MeV/nucleon(d)

0 3 6 9 12

200 MeV/nucleon(e)

0 3 6 9 12

Soft

SMD

400 MeV/nucleon(f)

Coulomb On

30 60 100 200 4001.0

1.5

2.0

2.5

3.0

Soft

SMD

Energy (MeV/A)

84

36Kr+

197

79Au Coulomb On

The distributions decrease monotonically with increase in

the fragment's charge at all incident energies

Trends in the displayed values of tau for both soft and SMD

cases are almost in accordance with those observed for light

charged systems

Page 26: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 26

10-3

10-2

10-1

100

101

dN

/dZ

f

(a)

84

36Kr+

197

79Au

35 MeV/nucleon

Zf

55 MeV/nucleon

(b)

70 MeV/nucleon

(c)

0 3 6 9 1210

-3

10-2

10-1

100

100 MeV/nucleon(d)

0 3 6 9 12

200 MeV/nucleon(e)

0 3 6 9 12

Soft

SMD

400 MeV/nucleon(f)

Coulomb Off

30 60 100 200 4001.0

1.5

2.0

2.5

3.0

Soft

SMD

Energy (MeV/A)

84

36Kr+

197

79Au

Coulomb Off

Both equations of state lead to the onset of

multifragmentation

Page 27: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 27

0 15 30 45 6010

-6

10-4

10-2

100

102

104

Present

Data

32 MeV/nucleon

129

54Xe+

119

50Sn

0 15 30 45 60

39 MeV/nucleon

0 15 30 4510

-6

10-4

10-2

100

102

104

(c)

45MeV/nucleon

Zf

0 15 30 45

(d)

(b)

50 MeV/nucleon

dN

/dZ

f

(a)

Present aim is to concentrate on the yield

of intermediate mass fragments which lie in the

range 3≤Z≤12 to extract the critical exponents as well

as critical energy

Confrontation of IQMD model results with experimental measurements of INDRA collaboration for intermediate mass fragments

Calculated results for the yield of fragments are in nice

agreement with measured ones. Thus, IQMD

model is reliable in explaining the critical

exponents (first order liquid-gas phase transition in the

nuclear matter) at intermediate energy heavy-ion collisions.

Sou

rce of d

ata, Ph

ys. Rev. C

67

, 06

46

13

(20

03

).

Page 28: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 28

These results are published in the European Physical Journal A (Springer)

Isospin effects via Coulomb forces on the onset of multifragmentation in light and heavy charged systems.

Arun Sharma and Arun Bharti Eur. Phys. J. A. 52, 42 (2016) (Springer-Italy) [Impact factor- 2.73]

Page 29: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 29

It has been predicted that IQMD model with various refined ingredients is able to reproduce the measurements of asymmetric reactions and refutes the apprehension raised earlier that molecular dynamics approaches failed to give appropriate results (when compared with measurements) in the asymmetric heavy-ion collisions.

Apart from this, investigations have been made to probe the reason behind the different outcomes of a reaction for the multiplicity of intermediate mass fragments in asymmetric reaction with two different approaches (i.e., QMD and IQMD models). Interestingly, for the first time, it has been put forward that ingredients like symmetry potential and initial large Fermi-momentum of nucleons are responsible for the better reproduction of measured results for asymmetric reactions using IQMD model and these ingredients led to different results compared to results of the QMD model.

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7/16/2018 IWND2018 30

It has been found that Coulomb forces influence the onset of multifragmentation and result in the shift of the critical energy point towards lower and higher incident energies with and without their presence, respectively.

It has been noted that for the highly charged system, the critical energy point is sharp when compared with light charged system.

Very interestingly, the critical energy point predicted by the IQMD model is completely consistent with the one extracted using Percolation model by other research groups. Present Status Now we are working to probe role of different clusterization algorithms (as we have good number of these algorithims) on onset of multifragmentation.

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7/16/2018 IWND2018 31

It has been predicted that IQMD model with various refined ingredients is able to reproduce the measurements of asymmetric reactions and refutes the apprehension raised earlier that molecular dynamics approaches failed to give appropriate results (when compared with measurements) in the asymmetric heavy-ion collisions.

Apart from this, investigations have been made to probe the reason behind the different outcomes of a reaction for the multiplicity of intermediate mass fragments in asymmetric reaction with two different approaches (i.e., QMD and IQMD models). Interestingly, for the first time, it has been put forward that ingredients like symmetry potential and initial large Fermi-momentum of nucleons are responsible for the better reproduction of measured results for asymmetric reactions using IQMD model and these ingredients led to different results compared to results of the QMD model.

Page 32: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018

Further Reading: (http://www.worldscientific.com/worldscibooks/10.1142/10429)

32

We have made significant contribution to this book

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7/16/2018 IWND2018 33

Page 34: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018 IWND2018 34

Edited the abstract book (comprising of near about 100 abstracts) of one

day State level Science Conference held at GDC Thannamandi in Feb. 2017.

I was co-organizing secretary of the conference.

Edited the abstract book (comprising of near about 130 abstracts) of Two

day National Science Conference held at GDC Thannamandi on 19-20

March, 2018. Also I was organizing secretary of this conference.

http://gdcscienceconference.website/

Other work:

As organizing Secretary

As Co-organizing Secretary

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7/16/2018 IWND2018 35

Rohit Kumar, Samiksha Sood, Arun Sharma, Rajeev K. Puri, ACTA PHYSICA

POLONICA B , Vol. 49 (2018).

Use of Simulated Annealing Technique for Finding Most Bound Structures in Nuclear Reactions

Samiksha Sood, Ishita Puri, Rohit Kumar, Arun Sharma and Rajeev K. Puri International Journal of Pure and Applied Physics. ISSN 0973-1776 Volume 13, Number 1 (2017), pp. 201-204. On the relative role of temperature of fragments within the framework of quantum molecular dynamics model

Rohit Kumar, Arun Sharma, Samiksha Sood and Rajeev K. Puri International Journal of Pure and Applied Physics. ISSN 0973-1776 Volume 13, Number 1 (2017), pp. 17-20. Isospin effects on fragmentation in the asymmetric reactions induced by neutron-rich

targets. Arun Sharma AIP Conf. Proc. 1728, 020175 (2016) .

On the cluster formation and phase transition in nuclear disassembly using variety of

clusterization algorithms (Submitted in NPA)

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7/16/2018 IWND2018 36

Analysis of colliding matter in terms of symmetry energy and cross-section using computational method Arun Sharma, Sakshi Gautam and, Arun Bharti, AIP Conf. Proc. 1675, 030099 (2015). Study of Intermediate Energy Heavy-ion Collisions in Asymmetric Colliding Nuclei Using Computational Methods

Arun Sharma, Rohit Kumar, Samiksha Sood, and Rajeev K. Puri International Journal of Pure and Applied Physics. ISSN 0973-1776 Volume 13, Number 1 (2017), pp. 21-25.

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7/16/2018 IWND2018 37

ACKNOWLEGEMENTS

I acknowledge the HPC team at IUAC, Delhi for giving me access of High performance computer cluster facility and being helpful in different queries regarding the use of the facility.

I would also like to thank HPC team at Department of Physics, Panjab University, Chandigarh for giving me access of the facility in the department.

I am thankful to Prof. Ch. Hartnack from Subatech, France for fruitful discussions.

I am thankful to Prof. Rajeev K. Puri, Panjab University Chandigarh for guiding me and helping me in various stages of my research work.

Page 38: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

7/16/2018

It is not an end……It’s a first step towards new beginning…….

38 IWND2018

Page 39: IWND2018 - phys-hutc.net fileArun Sharma (In collaboration with Prof. Rajeev K. Puri, Panjab University, Chandigarh, India) Department of Physics, Govt. Degree College Thannamandi,

IWND2018

Big quark-gluon p + n low mass nuclei neutral atom star dispersion of TODAY

Bang plasma formation formation formation formation heavy elements

time 10-6s 10-4s 3 min 400,000 yr 109 yr >109yr 15x109yr

Copyright 1998 Contemporary Physics Education Project (CPEP)

...so much “heat” that we are actually forming a window back in time

7/16/2018 39

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7/16/2018 IWND2018 40

In this model, baryons are represented by Gaussian-shaped density

distributions.

)2

)(exp()2

1)(exp(

1),,(

2

22

22

Ltpp

Ltrrtprf

iii

.

ij

sym

ij

Coul

ij

Yukawa

ij

Skyrme

ijVVVVrrV )(

2)()(

1

21

rrrrtrrt

)()/)((

)/)(exp(2

3rr

eZZ

rr

rrt

ji

rrPPtt '1

2

'5ln 24

).(1

33

0

6 jiji rrTTt

,

V ijmdi

+

+

+

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7/16/2018 IWND2018 41

(4)

Here t6 = 4C with C = 32 MeV and Zi and Zj denote the charges of the ith and jth baryon,

and T3i and T3j are their respective T3 components (i.e. 1/2 for protons and -1/2 for

neutrons). The parameters µ and t1,....,t4 are adjusted to the real part of the nucleonic

optical potential. For the density dependence of the nucleon optical potential, standard

Skyrme-type parametrization is employed. The momentum dependence Vijmdi of the

nucleon-nucleon interactions, which may optionally be used in IQMD, is fitted to the

experimental data in the real part of the nucleon optical potential. We also use the

standard energy-dependent free nucleon-nucleon cross section. The elastic and inelastic

neutron-proton and proton-proton cross sections are discussed in detail in Ref. [33]. The

neutron-neutron cross section is taken to be equal to proton-proton cross section and

neutron-proton (np) cross section is approximated three times the proton-proton

(neutron-neutron) cross section due to the reason that proton-proton (pp) scattering

occurs only in states of total isospin T = 1 whereas np exists for T = 0 and 1. Two

particles collide if their minimum distance d fulfils

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7/16/2018 IWND2018 42

Parameters corresponding to the static and momentum-dependent potentials. K (MeV) α (MeV) β (MeV) γ δ (MeV) ε EOS 200 -356 303 1.17 - - Soft 380 -124 71 2.00 - - Hard 200 -390 (-3189)† 320 (-3176)† 1.14 (1.011)† 1.57 21.54 SMD 380 -130 (-63.13)† 59 (-49.42)† 2.09 (2.12)† 1.57 21.54 HMD

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7/16/2018 IWND2018 43

STABILITY TESTS

0 2 4 6 8 10 120.00

0.05

0.10

0.15

0.20

0.25

t=0fm/c

t=5fm/c

t=15fm/c

t=25fm/c

197

79Au

radius (fm)

den

sity

(r

) (f

m-3

)

0

2

4

6

8

0

2

4

6

0

2

4

6

0 50 100 150 2000

2

4

6

0.000

0.075

0.150

0.225

0.300

0.000

0.075

0.150

0.225

0 50 100 150 2000.000

0.075

0.150

0.225

0.000

0.075

0.150

0.225

rms

(r)

[fm

]

Time (fm/c)

Time (fm/c)

197

79Au

120

50Sn

6

3Li

40

20Ca

rms

(p)

[GeV

/c]