International Conference on Recent Issues in Nuclear and Particle Physics (RINP2)
Lipika Auditorium, Visva-Bharati, Santiniketan
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Registration & breakfast
Registration and Breakfast
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INAUGURAL SESSION
Lighting Lamp and inaugurating the session (10 minutes)
Welcome address by the convener (5 minutes)
Opening Remark: By Departmental Head, Department of Physics, Visva-Bharati and other dignitaries (15 minutes)
Keynote Address: “Opportunities for Nuclear and Particle Physics in India” by Prof. Amit Roy, Ex-Director, IUAC, New Delhi (35 minutes)
Vote of thanks: By one of the Conveners (5 minutes)
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1
Lighting Lamp etc
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2
Welcome speech by Anagha Chakraborty
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3
Opening Remark: By Departmental Head and other Dignitaries
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Opportunities for Nuclear and Particle Physics in India
Research in Nuclear and Particle Physics has been pursued in India over the past eight decades. It has gone through ups and downs in the past and currently many opportunities exist for pursuing research in these fields both in the country and abroad. I shall discuss some of these possibilities in this talk.
Speaker: Prof. Amit Roy (Ex-IUAC) -
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Vote of Thanks of Swarup Kumar Majee
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1
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11:05
High Tea
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Plenary: Session I
Talk 2: "Looking for dark matter: usual and unusual ways" by Biswarup Mukhopadhyaya, HRI, India (35 minutes)
Talk 3: “Nuclear Reactions using VEC: (1977 – 2017), A Journey over 4 decades” by C. Bhattacharya, VECC, India ( 35 minutes)-
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Looking for dark matter: usual and unusual waysSpeaker: Prof. Biswarup Mukhopadhyaya (Harish-Chandra Research Institute, Allahabad, India)
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7
Present and Future Developmental Activities of Modern Ion Accelerators and associated Research Facilities
Developments of various modern ion accelerators in India for delivering ion beams in a wide range of the energy have created new opportunities in carrying out innovative research and developmental activities. Focused research in the areas of nuclear physics, atomic and molecular physics, materials science and radiation biology using these state of the art accelerators are being carried out in the Country by a large number of researchers from all over India and abroad. Some of the innovative and interesting research and developmental activities undertaken by different accelerator centres in the country will be discussed systematically.
Speaker: Prof. D. Kanjilal (Inter-University Accelerator Centre (IUAC) Aruna Asaf Ali Marg, New Delhi 110067)
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6
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12:40
Photo Session
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13:00
Lunch
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Plenary Session II
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Composite Higgs PhenologySpeaker: Prof. Gautam Bhattacharyya (Saha Institute of Nuclear Physics)
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Building up for the next decade @ GANIL
The GANIL facility has a wide range beams ranging from intense stable and short-lived unstable beams (ISOL and fragmentation) including a variety of unique and state of art equipments. These are used to study the evolution of the properties of the quantum many body system, the nucleus, as a function of the three axis of nuclear physics namely excitation energy, angular momentum and the asymmetry of neutrons and protons.
In this talk we will introduce the facility and give an overview of the arsenal of tools and their upgrades at GANIL that provide new vistas for searching and understanding the simple and regular patterns that are found in the structure of complex nuclei and also to understand the dynamics of colliding nuclei. Highlights of recent results will be presented. The talk will also highlight among others the recent experiments done using the AGATA gamma array especially with the VAMOS spectrometer. The potential of the production of new isotopes around and beyond the neutron shell N=126 for nuclei below Pb by multinucleon transfer will also be shown. The current status of the of LINAC along with the associated equipment (SPIRAL2 phase 1) and future plans will also be discussed.Speaker: Prof. A. Navin (Grand Accélérateur National d'Ions Lourds, Caen, France) -
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Flavourful axion phenomenology
We provide a comprehensive discussion of the phenomenology of flavourful axions, including both standard Peccei-Quinn (PQ) axions, associated with the solution to the strong CP problem, and non-standard axion-like particles (ALPs). Presenting the general flavourful axion-fermion and axion-photon coupling, we calculate flavour-violating decays of mesons and leptons involving a flavourful axion. We also derive the mixing between axions and mesons which affects the meson oscillation probability and mass difference, and also contributes to meson decays into axions and axion decays into two photons. These effects may be relevant for ALPs. Finally we describe the phenomenology of a particular "A to Z" Pati-Salam model, in which PQ symmetry arises accidentally due to discrete flavour symmetry. Here all axion couplings are fixed by a fit to flavour data, leading to sharp predictions and correlations between flavour-dependent observables.
Speaker: Prof. Eung Jin Chun (ejchun@kias.re.kr) -
11
Systematics of β- and γ-bands in the A = 160 region
By considering the nucleus as a vibrating liquid drop, and assuming the potential to be a function of the elongation β, and triaxiality γ, of the nucleus, the Bohr Hamiltonian can be solved to give the so-called K=0+, β-vibrational and K=2+ γ-vibrational bands. However, as summarized in the review by Garrett[1], very few of the observed 0+2 bands in deformed nuclei possess the properties expected of a β vibration. It is likely that the nature of the 0+2 levels in deformed regions differ according to the precise location of the Fermi level, and contain admixtures of β-vibrational, two-phonon, pairing, and shape-coexisting states.
At iThemba LABS, a systematic investigation of low-lying levels in the mass 160 region has been made. An extensive set of data on the low-lying, positive-parity bands in the nuclides between N = 88 and 92 and Sm to Yb has been obtained from γ-γ coincidence measurements following fusion-evaporation reactions optimized of the population of low-spin states. Some these results point to the role of quadrupole pairing in forming 0+2 bands[2].
In this work, the energies and electromagnetic properties of the so-called β- and γ-bands of nuclei in this region are compared with the solutions of a five dimensional collective Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with moments-of-inertia and mass parameters determined by constrained self-consistent relativistic mean-field calculations using the PC-F1 relativistic functional[3,4]. This model is able to account for features such as vibrations and shpe-coexistence on al equal footing.
A good qualitative agreement is found between the measured energies and of the in-band/out-of-band branching ratios across the entire region.
P.E. Garrett, J. Phys.G 100, R1 (2001).
J.F. Sharpey-Schafer et al., Eur. Phys. J. A47, 6 (2011).
T. Niksic et al., Phys. Rev. C79, 034303 (2009).
Z.P. Li et al., Phys. Rev. C79, 054301 (2009).Speaker: Prof. R. Bark et al (iThemba LABS, South Africa) -
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A Pictorial History of Nuclear Instrumentation
The progress of nuclear instrumentation in the last hundred years is described. Some of the landmark discoveries, which became possible due to the development of new instrumentation, are explained. A connection between the early developments and the state of the art instrumentation is made.
Speaker: Prof. Ranjan Kumar Bhowmik (Inter University Accelerator Centre (Ex))
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8
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16:30
Tea Break
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Plenary Session III
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Nuclear Reactions using VEC: (1977 – 2017), A Journey over 4 decades
The Variable Energy Cyclotron (VEC), at Kolkata, recently completed its 40 years of operation in 2017. Several milestones have been achieved in experimental nuclear physics, using the light and heavy ions beams from this cyclotron during the last four decades. In this talk, an overview of the intense research activities carried out in nuclear reaction studies, using beams from cyclotron during the last four decades will be presented.
Speaker: Prof. C. Bhattacharya (Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata, INDIA chandana@vecc.gov.in ) -
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MSSM with Non-Standard Soft Interactions
Non-holomorphic soft supersymmetry breaking interactions will be discussed in relation to MSSM. Unlike MSSM, it is possible to have a higgsino as a single component type of dark matter candidate while having a low electroweak fine-tuning. Muon g-2 may also be enhanced. We will also explore the bottom squark sector by studying the 2b plus missing transverse energy signal at the LHC. We will probe parameter space that may potentially have an enhanced event rate than MSSM.
Speaker: Prof. Utpal Chattopadhyay (School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 India) -
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Weakly Bound Neutron-Rich Nuclei and Cosmic Phenomena
The study of single particle and bulk properties of the neutron-rich nuclei constrains fundamental issues of Nuclear physics like limits of existence of the quantum many body system ( atomic nucleus) and equation of state of neutron-rich matter etc [1-7]. This information has also important impact in understanding cosmic phenomena, like neutron star, nucleosynthesis, evolution of star etc...[1,6,7]. The state of art of Coulomb breakup of the neutron-rich nuclei has been used to explore those properties [1-9]. The unambiguous information on detailed components of the ground-state wave-function along with quantum numbers of the valence neutron of the nuclei obtained from the measurement of threshold strength along with the g-ray spectra following Coulomb breakup [1,3-5,9]. The shape of this threshold strength is a finger-print of the quantum numbers of the valence neutron. We investigated the ground-state properties of neutron-rich Na, Mg, Al nuclei around, island of inversion, N ~20 using this method at GSI, Darmstadt. Very clear evidences have been observed for melting and merging of long cherished magic shell gaps at N = 20,28 [4,9]. The evanescent neutron-rich nuclei imprint their existence in stellar explosive scenarios (r-process etc.). The indirect measurements are the only possible access to the information which is a valuable input to the model for star evolution process [6]. Some valuable bulk properties of the neutron-rich nuclei like density dependent symmetry energy, neutron skins etc. [7] play a key role in understanding densest object in the universe, the neutron star. I shall discuss our experimental investigation to obtain those information.
[1] Ushasi Datta et al., https://arxiv.org/abs/1810.08996
[2] A.Leistenschneider et al., Phys. Rev. Lett.86, 5442 (2001). P.Adrich et al., Phys. Rev. Lett.95 132501, (2005)
[3] U.DattaPramanik et al, Phy. Lett. B 551, 63 (2003).
[4] S. Chakraborty et al., Phy. Rev. C 96, 034301 (2017).
[5] A.Rahaman et al, J.Phys. G 44 ,045101 (2017).
[6] Ushasi Datta Pramanik , Prog. in part. Nucl. Phys.59, 183 ( 2007).
[7] ] A. Klimkiewicz et al., Phys. Rev. C76, 051503 (2007). D.M.Rossi et al., Phys.Rev.Lett.111, 242503 (2013)
[8] C.A.Bertulani and G.Baur, Physics Report 163, 299 (1988).
[9] Ushasi Datta et al., Phys. Rev. C 94, 034304 (2016).Speaker: Prof. Ushasi Datta (Saha Institute Of Nuclear Physics )
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13
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Poster Session with Tea & Snacks
Poster Session with Tea & Snacks
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Evening Lecture: Public Lecture
Evening Lecture by
Prof. Amitava Raychaudhuri (Palit Professor, University of Calcutta)-
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The knowns and unknowns of Neutrinos
In this talk the goal is to bring out why neutrinos hold a prominent place in today's physics. The neutrino is uncharged and interacts very weakly. As a consequence, over long distances it is a faithful messenger for information about its source, e.g., the sun. But the weakness of its interaction also makes neutrinos quite difficult to detect. The story of the neutrino is exciting and is yet to reach its completion. In this introductory talk, meant for non-experts, we discuss how we arrived at the present state of our knowledge about neutrinos and indicate the open issues which are being actively pursued.
Speaker: Prof. Amitava Raychaudhuri (University of Calcutta)
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16
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Dinner
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08:00
Breakfast
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Plenary Session IV
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The India based Neutrino Observatory, mini-ICAL and a shallow ICAL
The genesis of the India based Neutrino Observatory project is described briefly. The flagship experiment is based on a 51,000 ton magnetised iron calorimeter (ICAL) which aims to determine the mass ordering of the 3 tiny neutrino masses through a measurement of atmospheric muon neutrinos and muon anti-neutrinos. An 85 ton 4mx4mx10 layer mini- ICAL detector with 10 glass RPCs has been built and is presently taking data at the rented premises of INO at Madurai. The delay in starting construction at the preferred site in the Theni district in Tamil Nadu has encouraged us to look at other options for locating the ICAL detector including the possibility of a shallow depth ICAL together with an efficient cosmic veto shield. The first steps towards examining this possibility are outlined.
Speaker: Prof. V.M. Datar (INO Cell, TIFR) -
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Astroparticle physics of neutrinos
Neutrinos with energies ranging from meV to EeV pervade the universe,
and play crucial roles in astrophysics and cosmology. This talk will describe
the rich phenomenology of these astrophysical neutrinos, and how their
future observations will enrich our knowledge of particle physics,
astrophysics, and cosmology.Speaker: Prof. Amol Dighe -
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Investigation of nuclear overlaps near the neutron dripline
Direct reactions are known to provide access to crucial nuclear structure information e.g. the quantum overlap between the ground state wave function of an initial nucleus and the states populated by the reaction. The case of light nuclei is of particular interest as direct reaction experiments involving isotopes at the dripline can be implemented, providing access to the nuclear overlaps at the extreme of the chart. Moreover, the possibility to perform full ab initio calculation of overlaps and use those as nuclear structure inputs in reaction calculations may provide a stringent test of these models. I will present results focusing on the <Li|Be> overlaps through the study of proton transfer reaction on neutron-rich Lithium isotopes. I will also introduce present investigations of clustering properties of light nuclei close to the neutron dripline using cluster knockout reactions. An experimental programme on the topic has just started at RIKEN/RIBF facility in Japan, accompanied by theoretical developments in reaction calculations [1]. In such experiments, multineutron systems, which represent a subject of interest in nowadays Nuclear Physics can also be investigated. Recent studies and outlooks on the topic will be briefly discussed.
[1] M.Lyu et al., Phys. Rev. C 97, 044612 (2018)Speaker: Prof. D.Beaumel (Institut de Physique Nucléaire, CNRS/IN2P3, Université de Paris Sud, Université de Paris-Saclay, 91406 Orsay, France)
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11:00
Tea Break
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Plenary Session V
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How atomic nuclei polarize
Empirical drops in ground-state nuclear polarizabilities indicate deviations from the effect of giant dipole resonances and may reveal the presence of shell effects in semi-magic nuclei with neutron magic numbers N = 50, 82 and 126. Similar drops of polarizability in the quasi-continuum of nuclei with, or close to, magic numbers N = 28, 50 and 82, could reflect the continuing influence of shell closures up to the nucleon separation energy. These findings strongly support recent large-scale shell-model calculations in the quasi-continuum region, which describe the origin of the low-energy enhancement of the photon strength function as induced paramagnetism, and assert the generalized Brink-Axel hypothesis as more universal than originally expected.
Speaker: Prof. J. N. Orce (Institution: Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa) -
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Spectroscopy of nuclei at the N~Z line at GANIL
Nuclei in the vicinity of the N~Z line form a unique laboratory for studying many different phenomena among which the interplay of T=0 and 1 states at low energy, the role of neutron–proton pairing correlations, the shape coexistence along the N=Z line, the role of isospin symmetry and to which extent it is violated. A special emphasis is put on the heaviest N=Z nuclei located to the doubly magic N=Z=50, 100Sn nucleus, a key element in the Segré chart to adjust the interaction used in shell-model calculations as well as to delineate precisely the proton dripline. In addition, and connected to this latter point, these nuclei lie along the explosive rp-process nuclear synthesis pathway and, hence, their low-lying structure may be of interest in determining reaction rates.
For these numerous motivations, nuclei lying at or close to the N=Z line have been extensively studied at GANIL and in particular in the last months using a complex experimental setup consisting of the AGATA tracking array, the NEDA neutron detector and the DIAMANT charged particle detector. This powerful coupling of efficient detectors, made it possible to address several of the key questions mentioned above. This experimental campaign, as well as earlier results obtained along the N=Z line, will be presented and some of the main topics which, have been addressed, will be reviewed in a more detailed way.Speaker: Prof. G de France ( GANIL, for the AGATA-NEDA-DIAMANT collaborations) -
22
EMMA- the recoil mass spectrometer at TRIUMF
The ElectroMagnetic Mass Analyser (EMMA) is a new experimental facility at TRIUMF. Located after the ISAC-II accelerator, EMMA is a symmetric QQEDEQQ-type mass spectrometer capable of separating recoiling nuclear reaction products from the beam. With the low emittance radioactive beams delivered from ISAC-II at energies up to at least 6.5 A MeV, EMMA is designed for fusion evaporation and transfer reactions of interest in nuclear structure and astrophysics studies. A vacuum mode separator, EMMA disperses ions according to mass/charge in the focal plane. During successful commissioning runs over the last year, the angular, energy, and mass acceptances as well as the dispersion were characterized. EMMA is currently being coupled with the TIGRESS γ-ray detector array, to perform detailed in-beam spectroscopy. Today, we present the current status of the EMMA mass spectrometer as it begins its experimental life.
Speaker: Dr Nicholas Esker (TRIUMF) -
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Looking for Extra Dimensions at the Large Hadron ColliderSpeaker: Prof. Anindya Datta (University of Calcutta)
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20
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13:00
Lunch
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Parallel Session Nuclear Physics
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Nuclear Structure properties significant to neutrinoless double beta decay of 124Sn
The decay rate of neutrinoless double beta process is expected to give the first direct measure of the neutrino mass, if the corresponding nuclear matrix element can be reliably calculated [1]. A major complication in extracting the neutrino mass from the half-life of this decay is the uncertainty in the nuclear matrix element. There are certain experimental observable that may be placed to constrain the calculations of the matrix element [2]. One of the main ingredients in calculating the nuclear matrix element is the wave functions of the initial and final states, which are usually calculated based on different nuclear models [1, 2]. Single-nucleon transfer reactions can be used to probe the occupancy and vacancy of valence orbitals which can help to characterize the ground-state wave functions. The precise measurement of both neutron addition and removal cross-sections can be used to determine the occupation of valence orbits relevant to 0ν2β-decay, following the Macfarlane and French sum rules [3]. The method consists of requiring a normalization such that for a given orbit characterized by total angular momentum j, the sum of the measured occupancy and vacancy on the same target add up to the degeneracy of the orbit 2j+1. It has been shown that such measurements allowed for a detailed description of the energy and vacancy of the valence orbitals of 76Ge and 76Se, where 76Ge is a candidate for 0ν2β-decay. The results indicated that the Fermi surface is much more diffuse than in theoretical calculations [4]. Similar measurements have been recently performed on 130Te and 130Xe [5]. Both 76Ge and 130Te are subject of research for 0ν2β-decay programs known as GERDA, Majorana (for 76Ge) and CUORE (for 130Te).
In the present talk a brief review of the research activities in this direction along with the results from our recent measurements to study neutron pickup and stripping transfer cross- sections on one of the 0ν2β-decay candidate 124Sn and its daughter 124Te will be presented. This nucleus is the focus of neutrino-less double beta decay study, at the upcoming underground India based Neutrino Observatory (INO). This information will be useful for constraining calculations of the nuclear matrix element for the 0ν2β-decay of 124Sn. References [1] H. Ejiri, and F. Simkovic, Rep. Prog. Phys. 75, 106301 (2012). [2] S. J. Freeman and J. P. Schiffer, J. Phys. G: Nucl. Part. Phys. 39, 124004 (2012). [3] M. H. Macfarlane and J. B. French, Rev. Mod. Phys. 32, 567 (1960). [4] J. P. Schifferet al., Phys. Rev. Lett. 100, 112501 (2008). [5] T. Bloxhamet al, Phys. Rev. C 82, 027308 (2010).
*Electronic address: aradhana@barc.gov.inSpeaker: Prof. A. Shrivastava (1Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085, India and 2Homi Bhabha National Institute, Anushaktinagar, Mumbai - 400094, India ) -
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Nuclear Structure and Decay Data Evaluation
Nuclear Data evaluation is a very essential part of Experimental nuclear research. The Nuclear Structure and Decay Data Evaluation evaluation is a source to many new experiments and new ideas, besides the standardization of experimental data.
Mass A=139 data evaluation led to a new experiment for measuring the half life of 139Ba which had several past measurements not in agreement. The same mass chain evaluation also dealt with several discrepancies, which were settled amicably. Similarly data evaluation
of many other mass chains has led to new questions. One important question is the quantum of measurement of half-life
values in all the experimentally known nuclei. The analysis throws up interesting numbers on these measurements, indicating large
number of nuclei have very small number of half life values measured.
Same is the story on the quantum of measurement of values of spins and parity values of these nuclei. In the talk
I will present some of these numbers.
Speaker: Prof. P.K.Joshi (President IJSO Faculty member, Member EC, BASE. Room No. 106, NIUS building Homi Bhabha Centre for Science Education, Tata Institute of Fundamental Research V.N.Purav Marg Mankhurd Mumbai 400 088 India) -
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Measurement of fusion excitation functions around the Coulomb Barrier for 18O + 116Sn systemSpeaker: Dr Kushal Kalita (Gauhati University)
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27
Isomers and the evolution of structure in Hg, Tl and Pb isotopes
The structure of nuclei around the line of stability with A~200 exhibits diverse excitation modes ranging from collective rotation, including decoupled and semi-decoupled bands, and isomeric states whose decay rates span a large range from enhanced to hindered in comparison with single-particle estimates. The evolution of collectivity and the gradual predominance of intrinsic excitations with increasing $Z$ from Hg ($Z$=80) to Pb ($Z$=82), as well as along an isotopic chain approaching the neutron shell closure at $N$=126, is evident. Isotopes of Hg, Tl and Pb which lie in this transitional region offer insight into the complex underlying nuclear interactions.
The excited level structure of a number of isotopes, $viz$. $^{197-202}$Hg, $^{199-203}$Tl and $^{202-204}$Pb, have been studied using fusion-evaporation and multi-nucleon transfer reactions. The experiments have been performed at the Inter-University Accelerator Centre and the Argonne National Laboratory with $\gamma $-ray coincidence data being recorded using the Indian National Gamma Array (INGA) and Gammasphere spectrometers. An extensive analysis of the data obtained in these experiments has been performed [1] resulting in considerable extension of the known level structure and identification of new isomeric states.
While the data have revealed a number of facets of the structure of these nuclei, a common theme is the observation of isomers with half-lives ranging from a few nanoseconds to hundreds of microseconds. The gamut of responsible excitation mechanisms is exemplified by the disparate configurations and decay modes of the isomers. A total of 12 isomers have been newly identified in Hg, Tl and Pb isotopes [2,3,4] and several previously established ones have been confirmed. These results allow for a systematic and thorough examination of nuclear structure in this region. An understanding of these results, particularly those for isomers, has been obtained in the context of empirical calculations using single-particle and pair-gap energies, and residual interactions obtained from experimental data and shell model calculations performed with the Oxbash code using the KHH7B interaction. The detailed results will be presented at the conference.
[1] S.K. Tandel $et$ $al$., Physics Letters B 750 (2015) 225.
[2] S.G. Wahid, S.K. Tandel $et$ $al$., Proceedings of the DAE Symposium on Nuclear Physics 63 (2018) 228.
[3] Poulomi Roy, S.K. Tandel $et$ $al$., Proceedings of the DAE Symposium on Nuclear Physics 63 (2018) 238.
[4] Saket Suman, S.K. Tandel $et$ $al$., Proceedings of the DAE Symposium on Nuclear Physics 63 (2018) 176.Speaker: Prof. S.K. Tandel (UM-DAE Centre for Excellence in Basic Sciences)
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24
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Parallel Session Particle Physics
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28
Signatures of Synchrotron Radiation from the Annihilation of Dark Matter at the Galactic Centre
We propose a fermionic dark matter model by extending Standard Model with a Dirac fermion and a real pseudoscalar. The fermion dark matter particle interacts with the Standard Model sector via the Higgs portal through a dimension five interaction term as also through a pseudoscalar interaction term. The parameter space of the model is then constrained by using the vacuum stability and perturbativity condition as also with the LHC constraints. They are finally constrained by the PLANCK results for dark matter relic densities. The direct detection limits are then ensured to have satisfied by the model. We then explore within the framework of the model, the possible signatures of synchrotron radiation from the annihilations of dark matter in the Galactic Centre region when the end product is $e^{+}e^−$. We consider the observational data from the radio telescopes namely SKA, GMRT and Jodrell Bank telescopes and compare our calculated synchrotron flux density with them and also with the results predicted by these experiments. We predict that the low frequency radio telescopes like GMRT, SKA, if operate at the peak frequencies obtained from our calculations should get a better r.m.s sensitivity.
Speaker: Prof. Debasish Majumdar (Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, HBNI 1/AF Bidhannagar, Kolkata 700064, India) -
29
Non-equilibrium statistical mechanics, Fermion dark matter and SN1987A cooling
Light dark matter(1 − 30 MeV) particles which can be pair
produced in electron-positron annihilation e − e + → χ χ inside the
supernova SN1987A core, take away the energy released in the supernova
SN1987A explosion. Working within the framework of q-deformed scenario
(non-equilibrium statistics) and using the Raffelt’s criteria on the
energy loss rate and the optical depth criteria on the free streaming
of the dark matter fermion, we find that the lower bound on the scale
Λ of the dark matter effective theory to be Λ ∼1.0E+07 TeV for m χ =
30 MeV. We will briefly address our recent work on the supernova and relic density constraints on leptophillic operators.Speaker: Dr PRASANTA DAS (B) -
30
Confinement and de-confinement aspects of fermion in lower dimensional field theoretical model and its symmetry, e.g. BRST and field dependent BRST
Lower dimensional field theoretical models, e.g. Schwinger model, Chiral Schwinger model, Non-Confining Schwinger model, Thirring-Wess model and its Chiral generation known as Chiral Thirring-Wess model are of great interest because the models can explain the mass generation via dynamical symmetry breaking. It was known that the Schwinger can explain the confinement of fermions. However, in the Non-confining Schwinger model fermions are found to get liberated. The usual Chiral Schwinger model also fails to describe the confinement aspect of fermions. But Chiral Schwinger model with a particular counter term can explain the confinement aspect of fermions too. All these models are exactly solvable and exact bosonization of these models are possible. The Schwinger model is the eldest of all. Only Schwinger is gauge invariant at the quantum mechanical level. Other models are not so. But Gauge invariant, as well as BRST invariant reformulation, of all these models is found possible. Extension of phase space is needed to make these models gauge symmetric. Since extension of phase space is needed to make these models invariant under gauge and BRST transformations. It is important to ensure that physical contents must remain unchanged in presence of the extension of phase space required to make these models Gauge as well as BRST symmetric. There are different approaches to show it. Field dependent BRST (FFBRST) transformation is a current development in this direction. These systematic developments related to these lower dimensional models will be the subject of my presentatio
Speaker: Dr Anisur Rahaman (Hooghly Mohsin College) -
31
Signatures of parton saturation at small-x
The parton saturation behaviour at small-x is shown in a semi-analytical solution of the nonlinear GLR-MQ equation with parton recombination corrections, which resembles the widely discussed BK saturation of gluons. The effect of gluon shadowing on the small-x and moderate-Q^2 behaviour of gluon and singlet quark distribution function is examined. The computed results are compared with different experimental data as well as global parametrizations. It is very fascinating to observe that the strong growth of parton density corresponding to the linear QCD evolution equations at small-x can be tamed by gluon shadowing. Our predictions for nonlinear parton density are also compared with the results for the integrated gluon density obtained from the BK equation. The resulting analytic expression for nonlinear gluon density further allows us to predict the logarithmic derivative of the singlet structure function dF_2^S(x,Q^2)/dlnQ^2 which also shows a tamed behavior in the small-x region due to shadowing corrections. The present calculation suggests that the saturation of parton density towards small-x can be interpreted as a dynamical balance between the splitting and the recombination processes of partons, without incorporating any other mechanism.
Speaker: Dr mayuri devee (University of Science and Technology, Meghalaya)
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28
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15:40
Tea Break
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Plenary Session VI
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32
Particle Physics implications of neutrinoless double beta decaySpeaker: Prof. Palash Pal (University of Calcutta)
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33
Supersymmetry: Present and Future
Discovery of Higgs boson confirms once again the stupendous success of
the Standard Model (SM) of particle physics. Nevethless, there are many
experimental and theoretical issues which SM fails to address convincingly,
leading us to think about more bigger description of the SM, i.e. beyond the
standard model physics. Among several beyond standard models, the supersymmetry
is the most popular candidate. In Large Hadron Collider experiment(LHC),
at CERN, Geneva, after the discovery of Higgs boson, the major thrust
area is to look for the signature of supersymmetry. Unfortunately,
so far no signal is found in data, resulting exclusions of masses
of various sparticles. However, the experiments still will
continue to look for it in future experiments with more energy and data.
In this talk we will discuss the various issues explaining the present status
of Supersymmetry and the future prospect of finding of it.
Speaker: Prof. Monoranjan Guchait (Tata Institute of Fundamental Research (TIFR)) -
34
Expanding Horizons of the Seniority Isomers
Nuclear isomers are beginning to play an ever important role in unravelling the nuclear structure changes at higher spins and excitations. The seniority isomers constitute a separate class of isomers which are not exactly spin isomers. Very recently, we have shown the emergence of a new class of seniority isomers for the first time, which decay by odd-multipole transitions. This finding has led to many additional findings and explanations of some of the longstanding puzzles in nuclear structure physics. For example, we could address one of the long standing puzzles in nuclear structure physics, that of a asymmetric and double hump behavior of the B(E2; 2+→0+) values across the chain of Sn isotopes. Using the simple Generalized Seniority approach, we are able to show that a change of dominating orbitals from g7/2 to h11/2 after the mid-shell is responsible for the observed behavior. This simple yet robust interpretation is supported by the shell model calculations. We further strengthen this interpretation by expanding the Generalized seniority approach to magnetic moments and quadrupole moments, which is also able to explain the observed features in other isotopic chains.
References:
Odd – tensor electric transitions in high-spin Sn-isomers and generalized seniority
BhoomikaMaheshwari and Ashok Kumar Jain
Physics Letters B 753, 122 (2016).
Asymmetric behavior of the B(E2 ↑; 0+ → 2+) values in 104 – 130Sn and generalized seniority
BhoomikaMaheshwari , Ashok Kumar Jain and Balraj Singh
Nuclear Physics A952, 62 (2016).
Generalized Seniority States and Isomers in Tin Isotopes
A.K. Jain and BhoomikaMaheshwari
PhysicaScripta92, 074004 (2017).
Δv= 2 seniority changing transitions in yrast 3- states and B(E3) systematics of Sn isotopes
BhoomikaMaheshwari, Swati Garg and A.K. Jain
Pramana – J. of Phys., Rapid Communication, 89, 75 (2017).
g-factor calculations from the generalized seniority approach
BhoomikaMahshwari and A.K. Jain
EPJ Web of Conf. 178, 02006 (2018).
Generalized Seniority Schmidt Model and g-factors in semi-magic nuclei
Under Review.Invited talk at the International Conference on “Recent Issues in Nuclear & Particle Physics”, February 3-5, 2019, Visva Bharti (Central University), Santi Niketan – 731235, West Bengal
Speaker: Prof. A.K. Jain (Amity Inst. Of Nucl. Sc. & Tech., Amity University, NOIDA *Department of Physics, University of Malaya, Kuala Lumpur, Malaysia) -
35
The Digital Way to the Heart of the Nucleus : Free Knowledge & Deep TruthsSpeaker: Prof. S.S. Ghugre (UGC-DAE-Consortium for Scientific Research, Kolkata 700 098, India)
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36
Is neutrino its own antiparticle?
The mass and nature of neutrinos play an important role in theories beyond the standard model. It is now well established that neutrinos have a non-zero mass, but whether the neutrino and anti-neutrino are the same (Majorana particle) or distinct (Dirac particle) is still an open question. At present, neutrinoless double beta decay (NDBD or 0𝜈𝛽𝛽), is perhaps the only experiment which can provide an answer to this key question. The normal double beta decay (2𝜈𝛽𝛽) process has been experimentally observed in 13 nuclei so far with a half-life in the range - 𝑇1/2~1018 𝑡𝑜 1024𝑦. The 0𝜈𝛽𝛽 decay violates conservation of lepton number and has implication in understanding the matter-antimatter asymmetry in the universe. Further, the nuclear β decay and double beta decay can provide the information on absolute effective mass of the neutrinos. Given the significance of the NDBD, there is a widespread interest worldwide employing a variety of novel techniques. This talk will give a brief overview of ongoing as well as proposed NDBD experiments, with an emphasis on challenges involved in these experiments. This talk will highlight various R&D aspects of the TIN.TIN (The India-based Tin Detector) to search for 0𝜈𝛽𝛽 in 124𝑆𝑛.
Speaker: Prof. Vandana Nanal (TIFR)
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32
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Poster Session with Tea & Snacks
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Cultural Program: 1. Esraj 2. Manipuri Dance
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Conference Dinner
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08:00
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Breakfast
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Plenary Session VII
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37
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 has 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, 11Li, 14Be, 20C 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 (Dept. of Nucl.& Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400 005, India) -
38
Beyond the Standard Model with Flavour
Flavour Physics is perhaps the only way to look beyond the Standard Model if the new particles are beyond the direct production reach of the LHC. While the three-generation CKM picture works very well, there are enough reasons to believe that this is only an effective theory. In this talk, I will discuss about the way flavour data can act as a window to the unexplored land of new physics, about some of the interesting anomalies and the possible patterns of new physics they point to.
Speaker: Prof. Anirban Kundu (University of Calcutta) -
39
Signature of supersymmetry and L_mu - L_tau gauge boson at Belle-II
In this talk we will discuss a proposal that the $\gamma$ + missing energy signal at the Belle-II detector will be a smoking gun for supersymmetry (SUSY) in the presence of a gauged $L_\mu - L_\tau$ symmetry. A striking consequence of breaking the enhanced symmetry appearing in the limit of degenerate (s)leptons is the non-decoupling of the radiative contribution of heavy charged sleptons
to the $\gamma - Z^\prime$ kinetic mixing. The signal process, $e^+ e^- \rightarrow \gamma Z^\prime \rightarrow \gamma$ + missing energy, is an outcome of this ubiquitous feature. We take into account the severe constraints laid down on gauged $L_\mu - L_\tau$ models by several low-energy observables and show that any significant excess in all but the highest photon energy bin would be an undeniable signature of such heavy scalar fields in SUSY coupling to $Z^\prime$. The number of signal events depends crucially on the logarithm of the ratio of stau to smuon mass in the presence of SUSY. In addition, the number is also inversely proportional to the $e^+-e^-$ collision energy, making a low-energy, high-luminosity collider like Belle-II an ideal testing ground for this channel. This process can probe large swathes of the slepton mass ratio vs the additional gauge coupling ($g_X$) parameter space. More importantly, it can explore the narrow slice of $M_{Z^{\prime}}-g_X$ parameter space still allowed in gauged $L_\mu - L_\tau$ models for superheavy sparticles.Speaker: Prof. Sourov Roy (Indian Association for the Cultivation of Science, Kolkata) -
40
Radii measurements of exotic nuclei
With large neutron-to-proton ratios far from the line of stability, nuclei develop exotic structures. Systematic studies of nuclear radii closer to the drip line have demonstrated the change of nuclear properties, such as the emergence of nuclear halo, development of neutron skin and the nuclear deformation. Halo nuclei show unexpected behavior, such as, large interaction cross section which in turn, points to large matter radius [1] and narrow momentum distribution of the valence neutrons. In this context, nuclei with two neutron halo are intriguing systems to understand the correlation between the two halo neutrons and the core. Borromean nuclei are such systems where the nucleus is bound with two halo nucleons but the combination of core and one halo nucleon is unbound. Two-neutron halos in Borromean nuclei have been identified along the dripline in the p-sd shell in 6He, 11Li, 14Be, 17,19B and 22C but its occurrence beyond the sd-shell, has not been fully investigated. Beyond sd-shell, in the N = 20 island of inversion region, one neutron halo configuration was found in 31Ne [2, 3] and 37Mg [4, 5].
An important question is how unusually the large extension of the neutron wave function influences the protons. This can be investigated by measuring the root mean square (rms) radii of the proton distribution. Charge radius which is a fundamental nuclear ground-state property, seems to be changing with the increase of valence neutrons. The proton radius is also necessary to understand the spatial correlation between the halo and the core. Furthermore, it is also crucial to determine the neutron-skin thickness if the matter radius is known. Complimentary to the traditional methods for determining the charge radius (or proton radius) which are isotope shift measurements and electron scattering measurements, charge-changing cross section measurement is a new tool which can be applied very well for stable nuclei and as well as for exotic nuclei far from the beta-stability line [6-8]. The radii are obtained from the cross sections through finite range Glauber model analysis of the reaction.
The rare isotope facility at GSI is unique in having energies up to 1 A.GeV. Experiments for precise radii measurements are best suitable at this energy as a wide variety of isotopes of interest could be fully ionized. It is also possible to perform such studies for light nuclei at beam energies around 200-300 MeV/u that are available at RIKEN.
In this presentation, I will discuss how the proton and matter distribution radii measurements of nuclei far from the line of stability can unfold the exotic structures.
References:
[1] I. Tanihata et al., PRL 55, 2676 (1985).
[2] M. Takechi et al., PLB 707, 357 (2012).
[3] T. Nakamura et al., PRL 112, 142501 (2014).
[4] N. Kobayashi et al., PRL 112, 242501 (2014).
[5] M. Takechi et al., PRC 90, 061305(R) (2014).
[6] A. Estrade et al., PRL 113, 132501 (2014).
[7] R. Kanungo et al., PRL 117, 102501 (2016)
[8] S. Terashima et al., Prog. in Theor. Exp. Phys. 101D02 (2014).Speaker: Dr Soumya Bagchi (GSI Helmholtzzentrum)
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37
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11:30
Tea Break
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Plenary Session VIII
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41
An overview of recent experimental results in nuclear cluster physics over the whole nuclear chart
This presentation will highlight some of most recent results concerning experiments
devoted to the understanding of cluster structures in atomic nuclei. Selected topics will
cover results from experimental studies on 12 C, self-conjugated and non-self-conjugated
nuclei, clustering effects in nuclear reactions with light partners, including those of interest
in nuclear astrophysics, and in the region of heavier mass nuclei. Effects attributable to
clustering will be further discussed in processes such as fission and quasifission, in the
heavy and superheavy mass region, where shell closures definitively play a role.Speaker: Prof. E. Vardaci (Dipartimento di Fisica “E. Pacini”, Universitá di Napoli "Federico II", 80126 Napoli, Italy and Istituto Nazionale di Fisica Nucleare, 80126 Napoli, Italy) -
42
Nuclear reactions and astrophysical s-process
Astrophysical s-process is among the principla processes which are responsible for creation of heavy elements beyond the iron peak nuclei. Radiative neutron capture reactions in the vicinity of nuclear shell closures are important to understand the abundance of various heavy elements. Semi-microscpic calculation has been carried out in isotopes near magic numbers for neutron capture reactions. Results of some of these calculations will be presented and their implications for elemental abundance will be discussed.
Speaker: Prof. Gautam Gangopadhyay (Department of Physics University of Calcutta) -
43
Nuclear Data Evaluation and ApplicationsSpeaker: Dr sukhjeet dhindsa
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41
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13:00
Lunch
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Parallel Session Nuclear Physics
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44
Nuclear structure studies at VECC using INGA
The study of the excited states in nuclei is the key to understand not only the structure of nuclei but also the modes of generation of angular momentum in nuclei and different quantum mechanical symmetries in nuclei. In order to predominantly excite a particular set of states in a nucleus, one has to choose a suitable reaction. For example, the heavy-ion induced fusion reaction mostly populates the high-spin yrast states while the lower spin and non-yrast states are populated mostly by light-ion induced reactions. Moreover, the higher spin states of heavy nuclei near the stability line can only be populated by light-ion induced reactions. At VECC, the K-130 cyclotron can provide both heavy ion and light ion beams at higher energies which gives the opportunity to access a wide range of nuclei in the nuclear chart. Therefore, a variety of structural phenomena can be experimentally addressed. Recently, an experimental campaign using the INGA (Indian National Gamma Array) setup with up to 10 Compton suppressed clover HPGe Detectors has been completed at VECC with an aim to exploit the advantages of the unique beams available at VECC in the study of the excited states in nuclei by \gamma-ray spectroscopy technique. A PIXIE-16 based digital data acquisition system, setup by the UGC-DAE-CSR, Kolkata Centre, was used in this campaign. A total of 23 experiments were carried out by different users from Universities and Institutions in India and abroad. The highlights of some of the experiments and the results will be presented.
Speaker: Dr Gopal Mukherjee (Vriable Energy Cyclotron Centre) -
45
Recent trends in the neutron and proton induced reaction cross section data for advanced reactor applications
The light particle induced reaction cross-section data are of prime interest for the different areas like radiation dose estimation, radiation damage, fuel cycle assessments, transmutation of long lived nuclei and many more. The future nuclear reactors like Accelerator Driven Subcritical systems (ADSs), International Experimental Thermonuclear Reactor (ITER) and fast breeder reactors demand the neutron and proton induced reaction cross-sections data at high incident energies. The data will also be helpful for the advancement of medical accelerators and for the medical isotope production. We have made an attempt to understand the nature of the cross-section data for reactor fuel materials (238U, 232Th) [1, 2] and structural materials (Sn, Tb, W, Gd, Ni, Al, In) [3,4,5] within the neutron energies from threshold to 22 MeV. The proton induced reaction cross-sections were also measured for the reactor structural materials (Ag, Ti, Nb, and Sn) [6, 7] within 10-22 MeV energies. In addition to this, we have also measured the cross-sections for the most demanding medical isotope 99mTc using two production routes 100Mo(n, 2n)99mMo [8] and 100Mo(p, 2n)99mTc.The experiments were carried out at the 14UD BARC-TIFR Pelletron accelerator utilizing the activation and off-line γ-ray measurement technique for both neutron and proton irradiations. The quasi-monoenergetic neutrons of desired energies were generated using the 7Li(p, n) (Eth = 1.88 MeV) reaction. The nuclear model codes like, TALYS-1.9 [9], ALICE-2014 [10] and EMPIRE-3.2.3 [11] were used for the theoretical predictions. The uncertainty in each measured data was calculated using the error propagation method [1]. The uncertainties together with the correlation coefficients were calculated for each case and were found to be within the range of 10-20%. The recent work emphasis the vitality of the reaction cross-section data for the reactor based applications. The work also highlights that the precise reaction cross-section data is achievable within 20% uncertainty by using the 7Li(p, n) reaction as the neutron generator.
REFERENCES
[1]. Siddharth Parashari et al., Phys. Rev. C 98 (2018) 014625.
[2]. S. Mukherjee et al., App. Rad. Isot. 143 (2019) 72–78.
[3]. Siddharth Parashari et al., Appl. Rad. Iso. 133 (2018) 31–37.
[4]. R. Makwana et al., Phys. Rev. C 96 (2017) 024608.
[5]. B.K. Soni et al., Appl. Rad. Iso. 141 (2018) 10-14.
[6]. Siddharth et al., Nucl. Phys. A 978 (2018) 160-172.
[7]. Siddharth et al., Nucl. Phys. A 979 (2018) 102-112.
[8]. Siddharth Parashari et al., 2018 19th International Scientific Conference on Electric Power Engineering (EPE). ) https://doi.org/10.1109/EPE.2018.8395960.
[9]. A. J. Koning et al., TALYS user manual a nuclear reaction program, User manual. NRG-1755 ZG PETTEN, The Netherlands (2015).
[10]. M. Blann, Phys. Rev. C 54 (1996)1341.
[11]. M. Herman, et al., EMPIRE-3.2 Malta modular system for nuclear reaction calculations and nuclear data evaluation, INDC(NDS)-0603, BNL-101378-2013.Speaker: Prof. S. Mukherjee (Department of Physics, Faculty of Science, The M.S. University of Baroda, Vadodara-390002, India *sk.mukarejee-phy@msubaroda.ac.in ) -
46
Who is game changer in heavy-ion fusion reaction dynamics?
In heavy-ion fusion reactions, the energy of the projectile couples with the intrinsic degrees of freedom of the target during the collision process and this leads to a dissipative phenomenon. Consequently, the dissipation in the system causes the angular momentum hindrance during the fusion process. Here we have focused on the dissipative behavior of the fusing nuclei and its dependency on the incident energy. The dissipative evolution of the system depends not only on the entrance channel mass asymmetry but also on the incident energy, which was not mentioned in earlier studies. Moreover, the dissipative behavior of the fusing nuclei is also compared with respect to the entrance channel parameters like mass asymmetry α and the Coulomb interaction term ZPZT. The dissipation phenomenon decreases when the mass asymmetry increases and it increases when the Coulomb interaction term ZPZT increases.
Speaker: Dr Ajay Kumar (Department of Physics, Banaras Hindu University, Varanasi-221005, India) -
47
Fission dynamics in the Super Heavy Nuclei
Search for the new elements has been one of the major area of research activity in physics and
chemistry over last few decades. Elements up to 294Og (atomic number Z = 118) have been synthesized
successfully using fusion evaporation route, where either double magic nuclei 208Pb (in the synthesis
of Z = 104 -113) or 48Ca (Z = 114 - 118) were extensively used due to extra stability achieved from their
spherical shell structure. But for the synthesis of elements beyond Z = 118, 48Ca beam can no longer
be used as in that case the other reaction partner required would be highly radioactive and currently
impossible to produce in sufficient quantities.
So it is extremely important to understand the reaction dynamics and its dependence on entrance
channel parameters like shell structure, isospin asymmetry and ground state deformation of the
reaction partners. A systematic study has been performed at the Australian National University using
other possible beams 50Ti, 54Cr along with 48Ca to understand the reaction dynamics which will be
presented during the talk.Speaker: Dr Kaushik Banerjee (Department of Nuclear Physics, Australian National University, Canberra, Australia Variable Energy Cyclotron Centre, Kolkata, India)
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44
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Parallel Session Paticle Physics
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48
Stability in the Minimal Type-III Seesaw Model
We study the minimal type-III seesaw model to explain the origin of the
non-zero neutrino masses and mixing. We show that the naturalness arguments
and the bounds from lepton flavor violating decay (μ → eγ) provide very
stringent bounds on the model along with the constraints on the stability
of the electroweak vacuum up to High energy scale. We perform a detailed
analysis of the model parameter space including all the constraints for both
normal as well as inverted hierarchies of the light neutrino masses. We find
that most of the region that are allowed by lepton flavor violating decay fall
into the metastable region.Speaker: Najimuddin Khan (Indian Institute of Technology Indore) -
49
Two component WIMP–FImP dark matter model with singlet fermion, scalar and pseudo scalar
We explore a two component dark matter model with a fermion and a scalar. In this scenario the Standard Model (SM) is extended by a fermion, a scalar and an additional pseudo scalar. The fermionic component is assumed to have a global U(1)$_{\rm DM}$ and interacts with the pseudo scalar via Yukawa interaction while a $ℤ_2$ symmetry is imposed on the other component – the scalar. These ensure the stability of both dark matter components. Although the Lagrangian of the present model is CP conserving, the CP symmetry breaks spontaneously when the pseudo scalar acquires a vacuum expectation value (VEV). The scalar component of the dark matter in the present model also develops a VEV on spontaneous breaking of the $ℤ_2$ symmetry. Thus the various interactions of the dark sector and the SM sector occur through the mixing of the SM like Higgs boson, the pseudo scalar Higgs like boson and the singlet scalar boson. We show that the observed gamma ray excess from the Galactic Centre as well as the 3.55 keV X-ray line from Perseus, Andromeda etc. can be simultaneously explained in the present two component dark matter model and the dark matter self interaction is found to be an order of magnitude smaller than the upper limit estimated from the observational results.
Speaker: Ms Madhurima Pandey (Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Kolkata 700064, India) -
50
Lepton polarization asymmetry in excited b-mesons
Recently, some unexpected phenomena in various B meson decays are being observed in several experiments. Few of the observables are branching ratio of $B_s→φμ^+ μ^-$ decay, angular observable $P_5$' in $B→K^* μ^+ μ^-$ decay, lepton flavour non-universality parameters $R_{K(^*)}$,$R_{D(^*)}$ etc. The fact that these observables show significant deviation around 3σ from their standard model (SM) values declares them as anomalies in recent time. To find the possible solutions scientists extend their ideas beyond the SM which points towards the presence of new physics (NP). There are various NP models like leptoquark, 2HDM, non-universal Z', fermion fourth generation etc which are being examined to see whether they could explain the recent anomalies. Here, we are interested to study the heavy-light systems like the $(b\bar{q})$ mesons which have a rich spectrum of excited states. We are mainly concerned about the decay $B_{(s,d)}^* →l^+ l^- (l=e,μ,τ)$ which includes $b→sll$ flavor-changing neutral-current (FCNC) transition. The excited mesons $B_{(s,d)}^*$ are unstable under electromagnetic and strong interactions and possess narrow width with corresponding lifetime of the order of $10^{-17}$ s. The $B_{(s,d)}^* →l^+ l^-$ decays are sensitive to short-distance structure of $ΔB=1$ transitions. Some theoretical studies are being done in ref. [1, 2] regarding these decay channels. The authors of ref. [1] have proposed a novel method to study FCNCs in the $B_{(s,d)}^*→e^+ e^-$ transition and predicted the branching ratio [1] $BR(B_{(s,d)}^* →e^+ e^- )=0.98×10^{-11}$. In ref. [2] $B_{(s.d)}^*→l^+ l^-$ decay modes have been studied in the SM and the branching ratio has been predicted as $BR^{SM} (B_{(s,d})^* →l^+ l^- )=(0.7-2.2)×10^{-11}$ for decay width $Γ=0.10(5)$ keV, irrespective of the lepton flavor. We have recently studied [3] $B_{(s,d)}^* →l^+ l^- (l=μ,e)$ decay in Z' model and predicted the branching ratio as $BR (B_s^* →l^+ l^- )=(1.5-2.2)×10^{-11}$ and $BR (B_d^* →l^+ l^- )=(1.7-2.2)×10^{-13}$.
Theoretical investigation of longitudinal lepton polarization asymmetry $(A_{P_L })$ is found to be more clean compared to the branching ratio of this decay channel as the observable $A_{P_L }$ is independent of the total width of $B^*$ meson which is not confirmed theoretically or experimentally. In this work, we first calculate the SM prediction of $A_{P_L }$ and then analyse its sensitivity to the non-universal Z' model [4] which is an extension of SM with an extra U(1)' symmetry. The main attraction of this NP model is that FCNC transitions could occur at tree level due to the off-diagonal couplings of non-universal Z' with fermions, which is not allowed under SM consideration. The relation between the electroweak interaction eigenstates and mass eigenstates induces GIM mechanism within SM due to which flavor changing neutral interaction (FCNI) becomes forbidden at tree level. However, the relation between the electroweak interaction eigenstates of NP and the mass eigenstates is not same as of the SM. In such a situation, Z' model could allow the tree level FCNC $b→sll$ transitions. As, $B_{(s,d)}^* →l^+ l^-$ decay modes are not observed experimentally till now, so these decays are expected to be used to test the flavour sector of the SM and search for NP.References
- A. Khodjamirian, T. Mannel and A. Petrov, JHEP 1511, 142 (2015).
- B. Grinstein and J. M. Camalich, Phys. Rev. Lett. 116, 141801 (2016).
- D. Banerjee, P. Maji and S. Sahoo, Int. Jour. Mod. Phys. A 32, 14, 1750075 (2017).
- P. Langacker, Rev. Mod. Phys. 81, 1199 (2009).
Speaker: Mrs PRIYA MAJI (NATIONAL INSTITUTE OF TECHNOLOGY DURGAPUR) -
51
A theoretical study of shape shifters on forth generation flavour - sterile neutrino
Interpretation of data from MiniBooNE experiment at Fermilab and liquid scintillator neutrino detector (LSND) with a two-neutrino oscillation model, i.e, muon neutrino to electron neutrino, shows that, MiniBooNE experiment confirms the fourth neutrino flavour. These flavour’s properties and behaviours raise a lot of opportunities and challenges to understand the universe. In this present work, during oscillation, i.e, shape shifting, neutrino’s mass and chirality and their velocity are to be considered. Experimentally, one of the dependent parameter on this muon neutrino oscillation is mass and zenith angle during the interaction. Similarly finding the other required parameters for this oscillation is another task. In this proposed model, nature of the shape shifter for the four flavours is discussed, in that idea fourth sterile neutrino is also in the part of oscillation. We believe that outcome of this trial model will pave the way to the clarity in the shape shifters within the four flavours.
Speaker: Ms Janani M R (Jain University, Bangalore, India)
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48
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15:50
Tea Break
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Valedictory Session
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The Bridge -- An open discussion among expertise and the students
An open discussion among the expertise of fields and UG, PG students and research scholars to sort out and solve various logistic problems.
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