Soureek Mitra

The angular-correlation asymmetry parameter for circularly polarized γ-rays following allowed β-decay has been measured for three nuclei: 56Co, 58Co and 134Cs. The polarimeter employed the usual forward Compton scattering of γ-rays. The measured asymmetry parameter A, and the Fermi matrix element MF, in these decays are as follows: The present available data on the measurements of the Fermi matrix element MF in different regions of the periodic table are reviewed in the light of isospin impurities of nuclear wave functions.

The directional correlation between the nonunique first-forbidden outer beta group of end-point energy 1855 kev in ${\mathrm{Eu}}^{154}$ and the 123-kev cascade gamma ray in ${\mathrm{Gd}}^{154}$ has been measured at twelve beta-ray energies. The measured beta-gamma correlation coefficient $\ensuremath{\epsilon}$ ranges from -(0.222\ifmmode\pm\else\textpm\fi{}0.013) to -(0.314\ifmmode\pm\else\textpm\fi{}0.017) in the beta-energy interval 1150 to 1700 kev, after correcting for the attenuation due to the extranuclear field effect by measuring the attenuation factor ${G}_{2}=0.71\ifmmode\pm\else\textpm\fi{}0.03$ in the 1277-123-kev gamma-gamma cascade in ${\mathrm{Gd}}^{154}$. The correlation coefficient $\ensuremath{\epsilon}$ varies almost as ($\frac{{p}^{2}}{W}$) in this energy interval. The attenuation effect on the beta-gamma correlation coefficient under different physical conditions of the source has been demonstrated experimentally. An analysis of the data by an electronic computer leads to values of the matrix element ratios (Kotani's notation): $z=1$, $x=0.5\ifmmode\pm\else\textpm\fi{}0.05$, $u=0\ifmmode\pm\else\textpm\fi{}0.05$, and $Y=1.55\ifmmode\pm\else\textpm\fi{}0.10$. It is concluded that the "modified ${B}_{\mathrm{ij}}$ approximation" is reasonably valid in this beta decay.

The circular polarization of gamma radiation following allowed beta decays of the type 3−β 3− has been measured in three complex nuclei. The polarimeter employed the forward Compton scattering of gamma rays. The performance of the polarimeter has been checked by measuring the known beta-circularly polarized gamma correlation in 60Co and 22Na. The measured asymmetry parameter A and the isobaric spin impurity coefficient α which account for the Fermi component in the mixed decays are as follows: Aα · 103152Eu0.15±0.02(3.1±3.1)×10−3124Sb0.30±0.030.53±0.1372Ga−0.13±0.046.3 ±0.9

Aquaporins (AQPs) are ubiquitous channel proteins that play a critical role in the homeostasis of the cellular environment by allowing the transit of water, chemicals, and ions. They can be found in many different types of cells and organs, including the lungs, eyes, brain, glands, and blood vessels. By controlling the osmotic water flux in processes like cell growth, energy metabolism, migration, adhesion, and proliferation, AQPs are capable of exerting their regulatory influence over a wide range of cellular processes. Tumour cells of varying sources express AQPs significantly, especially in malignant tumours with a high propensity for metastasis. New insights into the roles of AQPs in cell migration and proliferation reinforce the notion that AQPs are crucial players in tumour biology. AQPs have recently been shown to be a powerful tool in the fight against pathogenic antibodies and metastatic cell migration, despite the fact that the molecular processes of aquaporins in pathology are not entirely established. In this review, we shall discuss the several ways in which AQPs are expressed in the body, the unique roles they play in tumorigenesis, and the novel therapeutic approaches that could be adopted to treat carcinoma.

A 2.45 GHz electron cyclotron resonance (ECR) ion source coupled to a gas-jet skimmer system has been developed for the online production of radioactive ion beams (RIBs). Using radial injection of gas jet in the ion source, RIBs of 11C1+, 11CO21+, and 11CO1+ have been produced online with beam intensity up to about 9 × 103 particles per second for a 1 µA primary proton beam bombarding a nitrogen gas target. The details of the gas jet coupled ECR ion source and the results for stable isotope beams and RIBs are reported.

In this work, we explore the use of deep learning techniques to learn the relationships between nuclear cross-sections across the chart of isotopes. As a proof of principle, we focus on the neutron-induced reactions in the fast energy regime that are the most important in nuclear science and engineering. We use variational autoencoders (VAEs) and implicit neural representations (INRs) to build a learned feature representation space of nuclear cross sections and reduce the dimensionality of the problem. We then train graph neural networks (GNNs) on the resulting latent space to leverage the topological information encoded in the chart of isotopes and to capture the relationships between cross sections in different nuclei. We find that hypernetworks based on INRs significantly outperforms VAEs in encoding nuclear cross-sections. This superiority is attributed to INR's ability to model complex, varying frequency details, which enables lower prediction errors when combined with GNNs. We also observe that GNN optimization is much more successful when performed in the latent space, whether using INRs or VAEs. However VAEs' continuous representation also allows for direct GNN training in the original input space. We leverage these representational learning techniques and successfully predict cross sections for a 17x17 block of nuclei with high accuracy and precision. These findings suggest that both representation encoding of cross-sections and the prediction task hold significant potential in augmenting nuclear theory models, e.g., providing reliable estimates of covariances of cross sections, including cross-material covariances.

Absolute cross sections for dissociative attachment of electrons to the ground and electronically excited states have been measured using the relative flow technique. The excited molecules were prepared by laser optical pumping and their fraction was determined from the reduction in the dissociative attachment signal from the ground state. The cross sections for the excited state were determined by normalizing to this fraction. The success of this experiment should lead to similar measurements on other molecules.

A measurement of the Higgs boson Yukawa coupling to the top quark is presented using proton-proton collision data at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$, recorded with the CMS detector. The coupling strength with respect to the standard model value, $Y_\mathrm{t}$, is determined from kinematic distributions in $\mathrm{t\bar{t}}$ final states containing ee, $μμ$, or e$μ$ pairs. Variations of the Yukawa coupling strength lead to modified distributions for $\mathrm{t\bar{t}}$ production. In particular, the distributions of the mass of the $\mathrm{t\bar{t}}$ system and the rapidity difference of the top quark and antiquark are sensitive to the value of $Y_\mathrm{t}$. The measurement yields a best fit value of $Y_\mathrm{t} =$ 1.16 $^{+0.24}_{-0.35}$, bounding $Y_\mathrm{t}$ $\lt$ 1.54 at a 95% confidence level.

Partial L X-ray production cross sections for proton bombardment of Au, Bi and U have been systematically measured in the energy range 0.3 to 1.8 MeV. This targets have been used in transmission geometry. For Bi and U, detailed low-energy measurements are reported here for the first time. Intensity ratios Ialpha /Ibeta ,Ialpha /Igamma and Ialpha /Il have been as a function of proton energy. Data are compared with the theoretical predictions of the PWBA and the PWBA with Coulomb deflection and binding corrections. There are indications that inclusion of relativistic corrections in the PWBA substantially improves the agreement with experiment.

The directional correlation between the non-unique first-forbidden outer beta group of endpoint energy 2.31 MeV in Sb124 and the 0.603 MeV cascade gamma ray in Te124 has been measured at twenty six beta energies. The measured beta-gamma correlation coefficient ϵ ranges from −(0.186±0.016) to −(0.387±0.010) in the beta energy interval 0.95 to 2.20 MeV. Taking into account the existing data on shape correction factor and also the angular dependence of the beta gamma circular polarization coefficient ω, the relevant first-forbidden beta decay matrix element ratios have been extracted; the ratios of the matrix elements are (in Kotani's notation) x = 0.06±0.05, u = 0.15±0.05 and Y = 1.05±0.15. Absolute values of the matrix elements were obtained from the observed log ft value as |∫ Bij|/R = (1.0±0.2) × 10−2, |∫ r|/R = (7.5±6.4) × 10−4, |∫ iσ × r|/R = (15.5±5.9) × 10−4, |∫ iα| = (7.0±2.1) × 10−4. The experimental ratio of ∫ iα/∫ r agrees with the predictiction of the conserved vector current theory of beta decay.

The directional correlation between the nonunique first-forbidden outer beta group of end-point energy 2.175 MeV in ${\mathrm{La}}^{140}$ and the 1.6-MeV cascade gamma ray in ${\mathrm{Ce}}^{140}$ has been measured at nine beta energies. The measured beta-gamma correlation coefficient $\ensuremath{\epsilon}$ ranges from (0.080\ifmmode\pm\else\textpm\fi{}0.010) to (0.111\ifmmode\pm\else\textpm\fi{}0.020) in the beta-energy interval 1.6 to 2 MeV. Taking account of the existing data on shape correction factor and also the beta-gamma circular polarization coefficient $\ensuremath{\omega}$ for $\ensuremath{\theta}=160\ifmmode^\circ\else\textdegree\fi{}$ and $W=4.2$, the relevant first-forbidden beta-decay matrix-element ratios have been extracted; the ratios of the matrix elements are (in Kotani's notation) $x=\ensuremath{-}0.33\ifmmode\pm\else\textpm\fi{}0.15$, $u=\ensuremath{-}0.06\ifmmode\pm\else\textpm\fi{}0.06$, and $Y=\ensuremath{-}1.50\ifmmode\pm\else\textpm\fi{}0.20$. Absolute values of the matrix elements were obtained from the observed $\mathrm{ft}$ value as $\frac{|\ensuremath{\int}{B}_{\mathrm{ij}}|}{R}=(3.3\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, $\frac{|\ensuremath{\int}\mathrm{r}|}{R}=(1.3\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, $\frac{|\ensuremath{\int}i\ensuremath{\sigma}\ifmmode\times\else\texttimes\fi{}\mathrm{r}|}{R}=(0.2\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, $|\ensuremath{\int}i\ensuremath{\alpha}|=(4.3\ifmmode\pm\else\textpm\fi{}1.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. A cancellation among the vector-type matrix elements is apparently the cause of the deviation from the $\ensuremath{\xi}$ approximation in this case.

Dissociative attachment of electrons to electronically excited produced by optical pumping is studied. An entirely new application of the dissociative attachment process has been demonstrated to unravel couplings between various states of a molecule which has not been possible by optical spectroscopy. Also, identification of a negative-ion resonance state based on initial state selection of the neutral molecule is achieved for the first time without making any angular distribution measurements.

The $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ directional correlation between $\ensuremath{\beta}$ particles in the 536-keV group and the 605- and 612-keV $\ensuremath{\gamma}$ rays in the decay of 72-day ${\mathrm{Ir}}^{192}$ has been measured at several $\ensuremath{\beta}$-ray energies. The measured correlation coefficient $\ensuremath{\epsilon}(W)$ rises from -0.074\ifmmode\pm\else\textpm\fi{}0.015 at 185 keV to -0.096\ifmmode\pm\else\textpm\fi{}0.010 at 255 keV and then starts falling; near the end-point energy the anisotropy is found to be very small. The large $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ anisotrophy observed conclusively establishes that the parity of ${\mathrm{Ir}}^{192}$ is negative. Attempts have been made to extract information about the relevant matrix-element ratios governing the 536-keV $\ensuremath{\beta}$ transition. The $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ directional correlation between $\ensuremath{\beta}$ particles in the outer group of 669-keV and the 469-keV $\ensuremath{\gamma}$ ray $({4}^{\ensuremath{-}}\stackrel{\ensuremath{\beta}}{\ensuremath{\rightarrow}}{4}^{+}\stackrel{\ensuremath{\gamma}}{\ensuremath{\rightarrow}}{2}^{+})$ has also been measured; it shows nearly isotropic correlation in the $\ensuremath{\beta}$ energy region 400-650 keV. The $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ circular-polarization correlation in the above cascade has also been measured. It is concluded that while large cancellation among the vector-type matrix elements is responsible for the observed energy dependence of the $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ anisotropy in the 536-keV $\ensuremath{\beta}$ group, the outer $\ensuremath{\beta}$ group of 669 keV apparently satisfies the quasi-allowed approximation. The nature of the 785-keV (${4}^{+}$) and 921-keV (${3}^{+}$) states in ${\mathrm{Pt}}^{192}$ is discussed in the light of these findings.

A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp $\to$ p$γγ$p with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb$^{-1}$ collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeV at the LHC. Events are selected with a diphoton invariant mass above 350 GeV and with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons matches the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% CL are $\lvertζ_1\rvert$ $\lt$ 2.9 $\times$ 10$^{-13}$ GeV$^{-4}$ and $\lvertζ_2\rvert$ $\lt$ 6.0 $\times$ 10$^{-13}$ GeV$^{-4}$.

The spin of the odd nucleus 228Ac(T12=6.13 h) has been determined to be I = 3 from the beta circularly-polarized gamma correlation studies on two prominent beta-gamma cascades: (i) the 1.19 MeV beta group (966 and 908) keV gamma rays and (ii) the 1.76 MeV beta group- 3.38 keV gamma ray. The matrix element ratio X for the 1.76 MeV beta transition has been determined to be X = 0.40±0.10.

The β-γ circular polarization correlation in the decay of 46Sc has been measured by means of forward Compton scattering. In addition to usual corrections that are applied to the data, the effect of transmission through the central lead stopper and scattering from coils etc. have been investigated. The effect of different source backings has also been studied. The value of the asymmetry parameter A in the β-γ circular polarization correlation was found to be A = 0.13±0.02. This implies a ratio X = −0.064±0.030 between Fermi and Gamow-Teller contributions.

Detailed level schemes, decay schemes, and the experimental data on which they are based are presented for all nuclei with mass number A=152. The experimental data are evaluated; inconsistencies and discrepancies are noted; and adopted values for level and γ–ray energies, γ intensities, as well as for other nuclear properties are given. This evaluation replaces the A=152 evaluation published by Agda Artna–Cohen in Nuclear Data Sheets 79, 1 (1996) and the evaluation for 152Dy prepared by Balraj Singh and published in Nuclear Data Sheets 95, 995 (2002).

L subshell ionisation cross sections for 4He ion impact on Au and Bi have been measured systematically in the energy range 0.9 to 1.8 MeV in steps of 0.1 MeV. Thin targets have been used in transmission geometry. Subshell ratios sigma 2s(12)// sigma 2p(12)/ and sigma 2p(32)// sigma 2p(12)/ have been obtained as a function of 4He ion energy. Data are compared with the theoretical predictions of the PWBA and PWBA with corrections due to Coulomb deflection of the projectile, increased binding of the target electron during collision and the relativistic nature of the target electrons. It appears that no single theoretical formulation gives overall agreement with data for all the three subshells.

The spectral shape and beta-gamma directional correlation of the 2.14 MeV (72− → 52+) beta-group in the decay of 139Ba have been studied. The spectral shape measured in coincidence with the 166 keV γ-ray shows a large deviation from a statistical shape. The beta-gamma directional correlation coefficient A2 varies from 0.01 to 0.06 in the energy region 0.5 to 2.0 MeV. The ratios of relevant nuclear matrix elements have been obtained from these two measurements. The absolute values of the matrix elements involved have been calculated from the known ft value. The matrix element ∫ ir has been found to be 3.9 × 10−3 (in natural units) as compared to a value of 7.1 × 10−3 calculated on the basis of the single-particle shell model. The structure of the 52+ state in 139La is discussed on the basis of these results.

Using the beam-foil technique and rather low beam energies (in the range 216-296 keV) in order to reduce cascade corrections, we have determined lifetimes for the , and terms of O II and compared them with predictions from various theoretical and experimental approaches. Our results support the claim for a short average lifetime. Experimental lifetimes for , and have been determined for the first time. The first two compare well with the opacity project results, whereas the experimental lifetime of level, a pseudo-five-electron system lying above the O II ionization limit, is a factor of four smaller.

The rich physics program at the high luminosity LHC (HL-LHC) requires all final state particles to be reconstructed with good accuracy.However, it also poses formidable challenge of dealing with very high pileup.Different identification algorithms need to be upgraded along with the detectors to improve the overall event reconstruction in such a hostile collision environment.The new timing device in the proposed CMS detector at the HL-LHC allows for the construction of timing observables at the track-level as well as at the jet-level.This information when given as inputs to the deep neural networks, have a potential to improve the existing algorithms used for heavy flavor (HF) jet tagging.In this paper, the latest developments on the studies for HF jet tagging performance at the HL-LHC are presented.

Abstract In order to compute optical absorption and fluorescence spectra, the harmonic oscillator model for molecular vibrations under Franck‐Condon approximation for optical transition at absolute zero temperature is often considered for ease of numerical simulation, which never truly reproduce the experimental spectra. In this article, we show how systematic introduction of realistic situation, i. e., anharmonicity of vibrations, thermalization and non‐adiabatic transition leading to failure of Franck‐Condon approximation plays a colossal role in determining the spectral shape of a model diatomic molecule. In particular, we investigate how the Huang‐Rhys parameter, describing the relative positioning of the ground and excited electronic surfaces, is correlated with the Stokes shift, considering both right‐ and left‐shifted potential wells, which is crucial to estimate changes in molecular length‐scale from experimentally determined quantities. Further, the result for iodine is shown to have excellent agreement with experimental absorption spectrum. These findings are promised to bring insights into origin of spectral shapes in complex polyatomic molecules.

The number of populations is increasing day by day. As populations no is being increased, the demand of food is also increasing simultaneously. Therefore, it’s easy to understand that no. of population growing is directly proportional to the demand of food. To increase the yield of food crops a large amount of chemical fertilizers is used every year. But certainly, these chemical fertilizers can cause long term damage to environment as well as on the bodies of those who will consume the grains also. In that case definitely we have to think some alternatives of chemical or artificial fertilizers. In addition, in spite of presence of sufficient amount of phosphate in soil, plant can’t get the access of phosphate as it forms complex with either inorganic metal ion or various organic compounds. On that note scientists and researchers have studied some microorganisms which can play very significant role in this critical situation. This microorganism live in rhizosphere region of plant and can increase soil fertility by solubilizing phosphate and also help in the development of plant. These are known as Phosphate Solubilizing Bacteria (PSB). This review discussed the different species of PSB, the mechanisms they follow to solubilize phosphate, their role in plant development. This research review also focuses on use of phosphate solubilizing bacteria for sustainable agricultural purpose.

Possible reactions of atomic nitrogen with SFx (X = 1–5) and CFx (X = 1–3) fragments resulting from discharges in N2 an or CF4 have been investigated using the flowing afterglow technique. It is shown that only in N2&.sbnd;SF6 discharges neutral NF is formed, by recording its fluorescence from the b 1Σ+ state of NF, presumably arising from the excitation transfer from N2(A 3Σ+u) to NF. It is argued that the reaction product NF results, in all likehood, from fluorine abstraction by atomic nitrogen from SF5.

A search for long-lived particles (LLPs) produced in association with a Z boson is presented. The study is performed using data from proton-proton collisions with a center-of-mass energy of 13 TeV recorded by the CMS experiment during 2016-2018, corresponding to an integrated luminosity of 117 fb$^{-1}$. The LLPs are assumed to decay to a pair of standard model quarks that are identified as displaced jets within the CMS tracker system. Triggers and selections based on Z boson decays to electron or muon pairs improve the sensitivity to light LLPs (down to 15 GeV). This search provides sensitivity to beyond the standard model scenarios which predict LLPs produced in association with a Z boson. In particular, the results are interpreted in the context of exotic decays of the Higgs boson to a pair of scalar LLPs (H $\to$ SS). The Higgs boson decay branching fraction is constrained to values less than 6% for proper decay lengths of 10-100 mm and for LLP masses between 40 and 55 GeV. In the case of low-mass ($\approx$15 GeV) scalar particles that subsequently decay to a pair of b quarks, the search is sensitive to branching fractions $\mathcal{B}$(H $\to$ SS) $\lt$ 20% for proper decay lengths of 10-50 mm. The use of associated production with a Z boson increases the sensitivity to low-mass LLPs of this analysis with respect to gluon fusion searches. In the case of 15 GeV scalar LLPs, the improvement corresponds to a factor of 2 at a proper decay length of 30 mm.

A measurement of inclusive four-jet production in proton-proton collisions at a center-of-mass energy of 13\TeV is presented. The transverse momenta of jets within $\lvert\eta\rvert \lt$ 4.7 reach down to 35, 30, 25, and 20 GeV for the first-, second-, third-, and fourth-leading jet, respectively. Differential cross sections are measured as functions of the jet transverse momentum, jet pseudorapidity, and several other observables that describe the angular correlations between the jets. The measured distributions show sensitivity to different aspects of the underlying event, parton shower, and matrix element calculations. In particular, the interplay between angular correlations caused by parton shower and double-parton scattering contributions is shown to be important. The double-parton scattering contribution is extracted by means of a template fit to the data, using distributions for single-parton scattering obtained from Monte Carlo event generators and a double-parton scattering distribution constructed from inclusive single-jet events in data. The effective double-parton scattering cross section is calculated and discussed in view of previous measurements and of its dependence on the models used to describe the single-parton scattering background.

Abstract The positive ion-negative ion neutralization reaction of molecular nitrogen ion (N2+) with F− and other negative ions such as SF5− has been studied using the flowing afterglow technique. It has been observed that the product neutral N2 is not only formed in an electronically excited state but is also vibrationally excited. The vibrational population distribution of the N 2 ( B 3 Π g ) product shows a non-Franck-Condon behavior with a peak at ν′ = 7 which may be attributed to the avoided curve crossing of the potential energy surface of the intermediate binary complex in the charge-separated N2+F− ion pair state with that of the neutral covalent N2(a)-F intermediate hypersurface and the energy degeneracy of N 2 ( a 1 Π g , ν′ = 1) and N 2 ( B 3 Π g , ν′ = 7) levels.

Measurements of single top quark production are presented, performed using CMS data collected in 2011, 2012 and 2015 at centre-of-mass energies of 7, 8 and 13 TeV respectively.The cross sections for the electroweak production of single top quarks in the t-channel and in association with W-boson are measured and the results are used to place constraints on the CKM matrix element V tb .In the t-channel the ratio of top and anti-top production cross sections is determined and compared with predictions from different parton density distribution functions.In the same channel, the inclusive cross-section in the fiducial volume is also measured.Measurements of top quark properties in single top quark production such as the top-quark polarisation, W-helicity in top quark decay and searches for anomalous couplings to photons are also presented.A search for the s-channel is also performed.

Charge-dependent anisotropy Fourier coefficients ($v_n$) of particle azimuthal distributions are measured in pPb and PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.02 TeV with the CMS detector at the LHC. The normalized difference in the second-order anisotropy coefficients ($v_2$) between positively and negatively charged particles is found to depend linearly on the observed event charge asymmetry with comparable slopes for both pPb and PbPb collisions over a wide range of charged particle multiplicity. In PbPb, the third-order anisotropy coefficient, $v_3$, shows a similar linear dependence with the same slope as seen for $v_2$. The observed similarities between the $v_2$ slopes for pPb and PbPb, as well as the similar slopes for $v_2$ and $v_3$ in PbPb, are compatible with expectations based on local charge conservation in the decay of clusters or resonances, and constitute a challenge to the hypothesis that the observed charge asymmetry dependence of $v_2$ in heavy ion collisions arises from a chiral magnetic wave.

Measurements of single top quark production are presented, based on the LHC data collected at centre-of-mass energies of 7, 8 and 13 TeV.The cross sections for the electroweak production of single top quarks in the t-channel as well as in association with W bosons are measured and the results are used to estimate the CKM matrix element V tb .In the t-channel, the ratio of top and anti-top production cross sections is determined and compared with predictions from different parton density distribution functions.Searches dedicated to the s-channel production at the LHC are also discussed.Further, searches for presence of any anomalous interactions at the tWb vertex beyond the predictions of the standard model are presented.These searches are carried out in the t-channel production mode by performing measurements of top polarization, helicities etc. from its decay products.Limits are obtained to constrain new physics.

Identification of hadronic jets originating from heavy flavor quarks in the final state is extremely important to study the properties of the top quark and the Higgs boson, along with various searches for signatures of new physics beyond the standard model.The latest developments in the identification algorithms based on deep learning methods make it an interesting topic also from a technical perspective.In this article, a summary of various identification algorithms along with their performance in simulation and pp collision data, in boosted and resolved topologies, will be presented.

The spin assignment of 1/sup -/ of the isomeric state of Eu/sup 152/ (T/ sub 1/2/= 9.2 hr) was tested by measuring the energy dependence of BETA /sub 1/ - gamma /sub 1/ directional correlation coefficient of the 1511-kev BETA -group and the 344-kev E2 gamma ray over the beta spectrum from 660 to 1400 kev. (R.E.U.)

The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapidity-dependent difference ($\Delta v_2$) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, $v_2$) between $\mathrm{D}^0$ ($\mathrm{\bar{u}c}$) and $\overline{\mathrm{D}}^0$ ($\mathrm{u\bar{c}}$) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of $\Delta v_2$. The rapidity-averaged value is found to be $\langle\Delta v_2 \rangle =$ 0.001 $\pm$ 0.001 (stat) $\pm$ 0.003 (syst) in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the $\mathrm{D}^0$ and $\overline{\mathrm{D}}^0$ mesons $v_2$ and triangular flow coefficient ($v_3$) as functions of rapidity, transverse momentum ($p_\mathrm{T}$), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt $\mathrm{D}^0$ meson $v_2$ values is observed, while the $v_3$ is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry.

A measurement of the top quark mass is performed using a data sample enriched with single top quark events produced in the $t$ channel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, recorded at $\sqrt{s}$ = 13 TeV by the CMS experiment at the LHC in 2016.Candidate events are selected by requiring an isolated high-momentum lepton (muon or electron) and exactly two jets, of which one is identified as originating from a bottom quark. Multivariate discriminants are designed to separate the signal from the background. Optimized thresholds are placed on the discriminant outputs to obtain an event sample with high signal purity. The top quark mass is found to be 172.13$^{+0.76}_{-0.77}$ GeV, where the uncertainty includes both the statistical and systematic components, reaching sub-GeV precision for the first time in this event topology. The masses of the top quark and antiquark are also determined separately using the lepton charge in the final state, from which the mass ratio and difference are determined to be 0.9952$^{+0.0079}_{-0.0104}$ and 0.83$^{+1.79}_{-1.35}$ GeV, respectively. The results are consistent with $CPT$ invariance.

Measurements of the inclusive and differential fiducial cross sections of the Higgs boson are presented, using the $\tau$ lepton decay channel. The differential cross sections are measured as functions of the Higgs boson transverse momentum, jet multiplicity, and transverse momentum of the leading jet in the event if any. The analysis is performed using proton-proton data collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb$^{-1}$. These are the first differential measurements of the Higgs boson cross section in the final state of two $\tau$ leptons, and they constitute a significant improvement over measurements in other final states in events with a large jet multiplicity or with a Lorentz-boosted Higgs boson.

The associated production of a W and a Z boson is studied in final states with multiple leptons produced in proton-proton (pp) collisions at a centre-of-mass energy of 13 TeV using 137 fb$^{-1}$ of data collected with the CMS detector at the LHC. A measurement of the total inclusive production cross section yields $\sigma_{\text{tot}}$(pp $\to$ WZ) = 50.6 $\pm$ 0.8 (stat) $\pm$ 1.5 (syst) $\pm$ 1.1 (lum) $\pm$ 0.5 (thy) pb. Measurements of the fiducial and differential cross sections for several key observables are also performed in all the final-state lepton flavour and charge compositions with a total of three charged leptons, which can be electrons or muons. All results are compared with theoretical predictions computed up to next-to-next-to-leading order in quantum chromodynamics plus next-to-leading order in electroweak theory and for various sets of parton distribution functions. The results include direct measurements of the charge asymmetry and the W and Z vector boson polarization. The first observation of longitudinally polarized W bosons in WZ production is reported. Anomalous gauge couplings are searched for, leading to new constraints on beyond-the-standard-model contributions to the WZ triple gauge coupling.

A search for new long-lived particles decaying to leptons using proton-proton collision data produced by the CERN LHC at $\sqrt{s}$ = 13 TeV is presented. Events are selected with two leptons (an electron and a muon, two electrons, or two muons) that both have transverse impact parameter values between 0.01 and 10 cm and are not required to form a common vertex. Data used for the analysis were collected with the CMS detector in 2016, 2017, and 2018, and correspond to an integrated luminosity of 118 (113) fb$^{-1}$ in the ee channel (e$\mu$ and $\mu\mu$ channels). The search is designed to be sensitive to a wide range of models with displaced e$\mu$, ee, and $\mu\mu$ final states. The results constrain several well-motivated models involving new long-lived particles that decay to displaced leptons. For some areas of the available phase space, these are the most stringent constraints to date.

The CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the collision. Yields of Z bosons are compared to Glauber model predictions and are found to deviate from these expectations in peripheral collisions, indicating the presence of initial collision geometry and centrality selection effects. The precision of the measurement allows, for the first time, for a data-driven determination of the nucleon-nucleon integrated luminosity as a function of lead-lead centrality, thereby eliminating the need for its estimation based on a Glauber model.