ScholarBank@NUShttps://scholarbank.nus.edu.sgThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 27 Jan 2020 12:38:11 GMT2020-01-27T12:38:11Z50221- A generalized multiplicity distribution for high-energy nucleus-nucleus collisionshttps://scholarbank.nus.edu.sg/handle/10635/95625Title: A generalized multiplicity distribution for high-energy nucleus-nucleus collisions
Authors: Chan, A.H.; Chew, C.K.
Abstract: We attempt to provide an explanation to the charged-particle multiplicity distributions in oxygen-nucleus collision at 60 and 200 GeV per nucleon obtained from Helios Collaboration which is based on an earlier work done on E T distributions. The differences between transverse energy (E T) distribution and multiplicity distributions will also be elucidated. © 1992 Società Italiana di Fisica.
Wed, 01 Jul 1992 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/956251992-07-01T00:00:00Z
- Multifractality and high energy multiparticle productionhttps://scholarbank.nus.edu.sg/handle/10635/97270Title: Multifractality and high energy multiparticle production
Authors: Chen, L.K.; Chan, A.H.; Chew, C.K.
Abstract: The multifractal behaviours of the various types of high energy collisions are analyzed using the normalized factorial moments which are calculated from the experimental data. The f(α) curves for the various types of collision are constructed. The 'width' of the f(α) curves seems to indicate roughly degree of intermittency or fluctuation of the data. The width of the curves also does not seem to be affected by the energy. © 1993 Springer-Verlag.
Wed, 01 Sep 1993 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/972701993-09-01T00:00:00Z
- A geometrical model for E T production in ultrarelativistic heavy-ion collisionshttps://scholarbank.nus.edu.sg/handle/10635/95627Title: A geometrical model for E T production in ultrarelativistic heavy-ion collisions
Authors: Chan, A.H.; Chew, C.H.
Abstract: We present a simple geometrical model in an attempt to study transverse energy, E T, distribution. Statistical comparisons are made on oxygen-A and sulphur-A scattering data, at 60 GeV and 200 GeV, obtained form Helios collaboration. © 1991 Società Italiana di Fisica.
Tue, 01 Jan 1991 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/956271991-01-01T00:00:00Z
- Friedberg-Lee symmetry and tribimaximal neutrino mixing in the inverse seesaw mechanismhttps://scholarbank.nus.edu.sg/handle/10635/96677Title: Friedberg-Lee symmetry and tribimaximal neutrino mixing in the inverse seesaw mechanism
Authors: Chan, A.H.; Low, H.B.; Xing, Z.-Z.
Abstract: The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact μ-τ symmetry in the gauge-singlet neutrino sector, and obtain the tribimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that nonunitary corrections to this result can possibly reach the percent level, and a soft breaking of μ-τ symmetry can give rise to CP violation in such a TeV-scale seesaw scenario. © 2009 The American Physical Society.
Tue, 13 Oct 2009 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/966772009-10-13T00:00:00Z
- Extraction of clan model parameters from multiplicity distributions measured in pp collisions at LHC energieshttps://scholarbank.nus.edu.sg/handle/10635/96581Title: Extraction of clan model parameters from multiplicity distributions measured in pp collisions at LHC energies
Authors: Dutta, S.; Jasvantlal, J.K.; Dewanto, A.; Chan, A.H.; Oh, C.H.
Abstract: This paper presents the variation of clan model parameters nc and N̄ with energy for p-p collisions at √s = 900 and 2360 GeV using ALICE and CMS as the detectors. The data for multiplicity distribution was reported by the ALICE and CMS collaborations. The values of n̄c and N̄ are evaluated from the NBD fit parameters n̄ and k. Hegyi [Phys. Lett. B 274, 214 (1992)] suggested an alternative method for determination of clan model parameters from void probability. A comparison of values obtained from the two methods is also done. A close agreement of values obtained from the two methods was observed for 546 GeV p-p̄ collisions. However for LHC data the agreement is not very well. Void probability overestimates the value of n̄c and underestimates the value of N̄ compared to that obtained from NBD. n̄c is found to increase with energy for both ALICE and CMS data. Contrary to the observation at lower energies that N̄ does not depend on energy, it is found to vary with energy. The variation of N̄ with energy is more prominent for CMS data. The results are discussed in detail. For CMS data, comparison of the results with the 7000 GeV data is also shown. © 2011 World Scientific Publishing Company.
Wed, 21 Dec 2011 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/965812011-12-21T00:00:00Z
- Void probability enhanced multiplicity distribution of produced hadrons in p-p collision at LHC energieshttps://scholarbank.nus.edu.sg/handle/10635/98567Title: Void probability enhanced multiplicity distribution of produced hadrons in p-p collision at LHC energies
Authors: Dutta, S.; Chan, A.H.; Oh, C.H.
Abstract: This paper studies the multiplicity distribution of hadrons produced in p-p collisions at 0.9 and 2.36 TeV using ALICE as a detector. The multiplicity distribution exhibits enhanced void probability. They are also found to satisfy the void probability scaling. The scaling of χ with n̄κ̄ 2 is studied using the generalized hypergeometric model. The variation of the parameter "a" of the hyper geometric model with energy and type of events is also studied. The parameter "a" distinguishes between various theoretical models, e.g. Lorentz/Catalan, negative binomial, geometric distribution etc. Finally a comparison is made with the p - p̄ collisions at 200, 546 and 900 GeV. It is observed both for p-p and p - p̄ data, the value of "a" decreases with increase in collision energy and approach towards the upper bound or the NB model of the void probability scaling. © 2012 World Scientific Publishing Company.
Thu, 30 Aug 2012 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/985672012-08-30T00:00:00Z
- Lee-Yang circle analysis for generalized multiplicity distributionhttps://scholarbank.nus.edu.sg/handle/10635/98778Title: Lee-Yang circle analysis for generalized multiplicity distribution
Authors: Dewanto, A.; Chan, A.H.; Oh, C.H.
Abstract: In this work, we study the Lee-Yang solutions of multiplicty distribution (MD) generating function for SPS energies range data. In particular, weighted generalized multiplicity distribution (GMD) function is used to describe the existing shoulder structure in the experimental data. Our study suggest that the existence of the shoulder structure in the KNO plot is accompanied by the forming of an ear structure in the Lee-Yang zeros plot. Prediction for the LHC energy range is also made. © World Scientific Publishing Company.
Thu, 01 Nov 2007 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/987782007-11-01T00:00:00Z
- Deviations from tribimaximal neutrino mixing in the type-II seesaw model and leptogenesishttps://scholarbank.nus.edu.sg/handle/10635/96209Title: Deviations from tribimaximal neutrino mixing in the type-II seesaw model and leptogenesis
Authors: Chan, A.H.; Fritzsch, H.; Luo, S.; Xing, Z.-Z.
Abstract: Current experimental data allow the zero value for one neutrino mass, either m1=0 or m3=0. This observation implies that a realistic neutrino mass texture can be established by starting from the limit (a) m1=m2=0 and m3≠0 or (b) m1=m2≠0 and m3=0. In both cases, we may introduce a particular perturbation which ensures the resultant neutrino mixing matrix to be the tribimaximal mixing pattern or its viable variations with all entries being formed from small integers and their square roots. We find that it is natural to incorporate this kind of neutrino mass matrix in the minimal type-II seesaw model with only one heavy right-handed Majorana neutrino N in addition to the SU(2)L Higgs triplet ΔL. We show that it is possible to account for the cosmological baryon number asymmetry in the m3=0 case via thermal leptogenesis, in which the one-loop vertex correction to N decays is mediated by ΔL and the CP-violating asymmetry of N decays is attributed to the electron flavor. © 2007 The American Physical Society.
Thu, 18 Oct 2007 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/962092007-10-18T00:00:00Z
- Lee-Yang circle analysis of e + e- and pp̄ generalized multiplicity distributionhttps://scholarbank.nus.edu.sg/handle/10635/97057Title: Lee-Yang circle analysis of e + e- and pp̄ generalized multiplicity distribution
Authors: Dewanto, A.; Chan, A.H.; Oh, C.H.; Chen, R.; Sitaram, K.
Abstract: We study the evolution of Lee-Yang zeros structure of generalized multiplicity distribution (GMD) in high energy collision. Starting our study with electron-positron e + e - scattering data, we extend the study by Chan and Chew (Z. Phys. C 55:503, 1992) on TASSO and AMY multiplicity data for √s=14, 22, 34.8, 43.6 and 57 GeV to the ones from DELPHI and OPAL Collaboration for √s=91, 133, 161, 172, 183 and 189 GeV. We compare the results with the Lee-Yang structure for proton-antiproton pp̄ at √s=546 and 900 GeV from UA5 Collaboration. Our preliminary result shows that there is indeed a change in the shape and size of the Lee-Yang zeros with increasing energy, accompanied by the development of the so-called "ear"-like structure in the Lee-Yang plot. We expect that the development of this "ear"-like structure is related to the "shoulder" structure in the multiplicity data, which further indicates an ongoing phase transition from soft to semihard scattering. We also extend our prediction to LHC's √s=14 TeV. Insert your abstract here. © 2008 Springer-Verlag / Società Italiana di Fisica.
Wed, 01 Oct 2008 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/970572008-10-01T00:00:00Z
- Non-cyclic phase for 4-flavor neutrino oscillationhttps://scholarbank.nus.edu.sg/handle/10635/97333Title: Non-cyclic phase for 4-flavor neutrino oscillation
Authors: Law, Z.Y.; Chan, A.H.; Oh, C.H.
Abstract: The non-cyclic phase for neutrino oscillation is calculated, taking into consideration a possible 4th sterile flavor. This extends the results derived in the paper by Xiang-Bin Wang et al. [X.-B. Wang, L.C. Kwek, Y. Liu, C.H. Oh, Phys. Rev. D 63 (2001) 053003] that discussed the non-cyclic phase in 3-flavor neutrino oscillation. A mathematical simplification is also introduced, making use of some of the transformation properties of the 4-flavor mixing matrix. The restriction that CPT symmetry imposes on the non-cyclic phase of neutrinos is also discussed briefly, with the possibility of further simplification of these phases. The scheme that we introduced is also applicable to 3-flavor neutrinos, and could yield more insights in 3-flavor mixing. Extending our result to ν to over(ν, ̄) oscillation could also help in resolving the issue concerning the Majorana or Dirac nature of neutrinos. © 2007 Elsevier B.V. All rights reserved.
Thu, 10 May 2007 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/973332007-05-10T00:00:00Z
- Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplingshttps://scholarbank.nus.edu.sg/handle/10635/127564Title: Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings
Authors: You Jia Bin; Shao Xiao Qiang; Tong Qing Jun; Chan Aik Hui; Oh Choo Hiap; Vedral Vlatko
Thu, 01 Jan 2015 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/1275642015-01-01T00:00:00Z
- e+e- multiplicity distribution from branching processhttps://scholarbank.nus.edu.sg/handle/10635/96283Title: e+e- multiplicity distribution from branching process
Authors: Chan, A.H.; Chew, C.K.
Abstract: We present a multiplicity distribution which is a solution to the stochastic branching equation proposed by Giovannini. This solution is more commonly known as generalized multiplicities distribution (GMD) and has already been successfully applied to both pp and p {Mathematical expression} collisions. It assumes that shapes and energy dependence of distributions are basically determined by hard parton scattering and subsequent branching. We apply GMD to the recent e+e- data by Tasso Collaboration. © 1992 Springer-Verlag.
Tue, 01 Sep 1992 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/962831992-09-01T00:00:00Z
- Analysis of generalized multiplicity distribution at various pseudorapidity rangeshttps://scholarbank.nus.edu.sg/handle/10635/95771Title: Analysis of generalized multiplicity distribution at various pseudorapidity ranges
Authors: Chan, A.H.; Chew, C.K.
Abstract: It is found that the data on multiplicity distributions of charged particles at various pseudorapidity ranges for inelastic, non single-diffractive events in {Mathematical expression} interactions at {Mathematical expression} GeV, can be well described by a generalized multiplicity distribution. The parameter k′ (average number of initial gluons) in the generalized multiplicity distribution appears to be close to zero wheres, 1.58≤k≤3.10 (k, related to the average number of initial quarks) at the different pseudorapidity ranges. © 1989 Società Italiana di Fisica.
Wed, 01 Mar 1989 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/957711989-03-01T00:00:00Z
- Parton branching model for pp» collisionshttps://scholarbank.nus.edu.sg/handle/10635/97496Title: Parton branching model for pp» collisions
Authors: Chan, A.H.; Chew, C.K.
Abstract: A detailed analysis of the behavior of the initial numbers of gluons and quarks in the generalized multiplicity distribution (GMD) is presented. Two special cases of GMD, namely, the negative-binomial distribution and the Furry-Yule distribution, are also discussed in relation to the non-single-diffractive data at 200, 546, and 900 GeV c.m.-system energies and pseudorapidity intervals c. The GMD may provide an alternate distribution to understand parton action for future pp» collisions at high TeV energies. © 1990 The American Physical Society.
Mon, 01 Jan 1990 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/974961990-01-01T00:00:00Z
- Nucleus-nucleus Chou-Yang correlations with generalized multiplicity distributionhttps://scholarbank.nus.edu.sg/handle/10635/98823Title: Nucleus-nucleus Chou-Yang correlations with generalized multiplicity distribution
Authors: Jasvantlal, J.K.; Dewanto, A.; Chan, A.H.; Oh, C.H.
Abstract: The Chou-Yang model has been successful in describing the forward-backward multiplicity distributions for Hadron-Hadron collisions. The model is extended to the case of Nucleus-Nucleus collisions where geometry is incorporated into the Generalized Multiplicity Distribution component. This contribution is investigated for forward-backward multiplicity measured at 130 GeV Au-Au collisions by calculating the correlation coefficient obtained with the model. Results are also produced for various oxygen-nucleus collisions. Finally the model is applied to the case of Pb-Pb collisions which can be extended to predict correlation coefficients in the TeV range.
Sat, 01 Jan 2011 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/988232011-01-01T00:00:00Z
- Non-relativistic neutrino oscillation in dense mediumhttps://scholarbank.nus.edu.sg/handle/10635/98815Title: Non-relativistic neutrino oscillation in dense medium
Authors: He, H.T.; Law, Z.Y.; Chan, A.H.; Oh, C.H.
Abstract: We first review the study of neutrino oscillation under non-relativistic energy and dense medium assumption. We then develop a computational model to study neutrino oscillation under this general scenario. In particular, we look at both the uniform medium and the linear medium cases, where various oscillation features are exhibited. The transition probability is found to depend on helicity for such cases. The neutrino mass dependence of the solution is also investigated.
Sat, 01 Jan 2011 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/988152011-01-01T00:00:00Z
- The Kolmogorov reverse equation and high energy multiplicity relationshttps://scholarbank.nus.edu.sg/handle/10635/98925Title: The Kolmogorov reverse equation and high energy multiplicity relations
Authors: Dewanto, A.; Chan, A.H.; Oh, C.H.
Abstract: Another solution to the Kolmogorov backward partial differential equation for stationary branching is proposed leading to a new multiplicity relation. This relation is applied to CERN's ISR and SPS energies, in which excellent fits are obtained and compared to Chaudhuri,1 Matinyan and Prokhorenko,2 and Golyak.3 Further prediction to the highly-anticipated 14 TeV data for pp collision is also made.
Sat, 01 Jan 2011 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/989252011-01-01T00:00:00Z
- Neutrino oscillation in dense mediumshttps://scholarbank.nus.edu.sg/handle/10635/97313Title: Neutrino oscillation in dense mediums
Authors: Law, Z.Y.; Chan, A.H.; Oh, C.H.
Abstract: It is found that a term normally discarded in the standard treatment of the MSW effect might be relevant in the case of non-adiabatic varying matter density, leading to a second order field equation, instead of the usual first order "Schrodinger equation". This leads to dispersion relation that gives rise to the possibility of neutrino trapping in a dense medium as well as the coupling of neutrino oscillation to neutral current interaction. This is found to be in agreement with previous results1. The corresponding conserved probability current is derived for this second order equation, and applied to the case of 2-flavor neutrino oscillation in a dense medium. The results in this work might be applicable to the oscillation of neutrinos in dense astrophysical medium. © 2009 World Scientific Publishing Company.
Thu, 30 Jul 2009 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/973132009-07-30T00:00:00Z
- Oscillatory moments in lee-yang zeros and lhc predictionshttps://scholarbank.nus.edu.sg/handle/10635/115220Title: Oscillatory moments in lee-yang zeros and lhc predictions
Authors: Dewanto, A.; Chan, A.H.; Lim, Z.H.; Oh, C.H.
Abstract: We study the moments of multiplicty distribution and its relation to the Lee-Yang zeros of the generating function in electron-positron and hadron-hadron high energy collision. Our work shows that GMD moments can reproduce the oscillatory behaviour as shown in the experimental data and predicted by quantum chromodynamics at preasymptotic energy, while it can also be used to distinguish electron-positron (e+e-) multiplicity data from hadron-hadron (pp and $p\overline p $) multiplicity. Furthermore, there seems to be a link between the development of shoulder structure in the multiplicity distribution and the development of ear structure in the Lee-Yang zeros. We predict that these structures is going to be very obvious at 14 TeV. We argue that the development of these structures indicates an ongoing transition from quark-dominated soft scattering events to gluon-dominated semihard scattering events. © 2009 World Scientific Publishing Company.
Thu, 30 Jul 2009 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/1152202009-07-30T00:00:00Z
- Asymptotic solution to the QCD-parton branching equationhttps://scholarbank.nus.edu.sg/handle/10635/95827Title: Asymptotic solution to the QCD-parton branching equation
Authors: Chan, A.H.; Chew, C.K.
Abstract: High-energy multiparticle production events have been heavily studied using varies models, particularly the QCD-based parton branching model first proposed by A. Giovannini [Nucl. Phys. B 161, 429 (1979)]. Presented here is an asymptotic solution that is the probability distribution by using a simple saddle point approach. Its mechanism and properties will also be elucidated. © 1992 American Institute of Physics.
Wed, 01 Jan 1992 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/958271992-01-01T00:00:00Z
- Charged multiplicity distribution in e+e- annihilation at LEP energieshttps://scholarbank.nus.edu.sg/handle/10635/95978Title: Charged multiplicity distribution in e+e- annihilation at LEP energies
Authors: Chan, A.H.; Chew, C.K.; Kiang, D.
Abstract: The negative binomal distribution (NBD) is used to describe the multiplicity distribution in e+e- annihilation at √s=91 and 184 GeV. Three different methods are used to determine the parameter k in the NBD. The results are compared with one another, as well as with the Krasznovszky-Wagner distribution (KWD).
Tue, 01 Jan 1991 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/959781991-01-01T00:00:00Z
- Chou-yang multiplicity correlations in high energy multiparticle production and lhc predictionhttps://scholarbank.nus.edu.sg/handle/10635/95989Title: Chou-yang multiplicity correlations in high energy multiparticle production and lhc prediction
Authors: Lai, W.C.; Chan, A.H.; Oh, C.H.
Abstract: A Chou-Yang Type multiplicity distribution which consists of a stochastic (binomial) component for z = nf - nb and a nonstochastic (Generalized Multiplicity Distribution) component for n = nf + n b, is used to analyze the forward-backward multipicity distributions for hadron hadron collision over a wide range of cms energy. The results are compared with the multiplicity distribution using the Negative Binomial Distribution. Finally, cluster size r = 3.30±0.14 and the correlation parameter b = 0.98 are predicted for 14 TeV. © 2009 World Scientific Publishing Company.
Thu, 30 Jul 2009 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/959892009-07-30T00:00:00Z