From RITA MARSHALL, By GERALDINE KEEN, Sale Room Correspondent, BY OUR DIPLOMATIC CORRESPONDENT, FROM OUR CORRESPONDENT, Our Lusaka Correspondent, By JOHN WOODCOCK, From Our Correspondent, BY A STAFF REPORTER, BY OUR AIR CORRESPONDENT, By Our Political Staff, By ARTHUR REED, FROM A STAFF REPORTER, By Our Broadcasting Correspondent, By ARTHUR REED, Air Correspondent, From Our Midland Correspondent, From RICHARD WIGG, From FRED EMERY, From Our Own Correspondent, From HAROLD FRANKLIN, From MICHAEL HORNSBY, From INNIS MACBEATH, By JOHN WOODCOCK, Cricket Correspondent, By REX BELLAMY, Tennis Correspondent., By GEOFFREY GREEN, By HARLEY GELLING, By PETER MARSON, From PETER RYDE, By Our Rifle Shooting Correspondent, By MICHAEL PHILLIPS, Racing Correspondent, By Our Northern Correspondent, By Our Newmarket Correspondent, By Our Racing Correspondent, By JIM SNOW, By DOUGLAS CALDER, By RONALD FAUX, Yachting Correspondent, By ANDREW PORTER, By CHARLES HARGROVE, By JOHN CLARE, PHS, From PETER NICHOLS, COLIN WEBB, C. WITTON-DAVIES., SALMA AL-KHALILI., NORMAN BENTWICH., SALAH EL SERAFY., WILLIAM HAMLING, CHARLES D. DRAKE, ERIC MOONMAN, A. A. RHODES., B. F. WALZER., MARK LENNOX-BOYD, From Anthony Smith, D. A. O. EDWARD, ELSPETH RHYS-WILLIAMS, D. I. URQUHART-PULLEN, By Dr. Daniel Jenkins, By Our Horticultural Correspondent, By Nature-Times News Service, Mr. T. Neil, By ANTHONY THOMAS Banking Correspondent, By CLIFFORD WEBB, BY DENNIS TOPPING, RODNEY COWTON, By DAVID DAVIS, By HUGH STEPHENSON, Economics Correspondent, By IAN MORISON, By R. W. SHAKESPEARE, BY THE FINANCIAL EDITOR, by MICHAEL THOMAS, by Jean Rhys, Stephen Walsh, Julian Critchley, John Russell Taylor, William Mann, JOHN PERCIVAL, Guy Brett, From Stanley Sadie, Caryl Brahms, David Wade, Michael Holroyd, Alan Bold, Roger Baker, Margaret Drabble, Jacky Gillott, Philippa Toomey, Paul Theroux, Peter Buckman, Edward Pinto, Katie Stewart, G. B. Berry, Andrew Graham, Edward Mayer, Frank Davis, Roy Hay, Harry Golombek, John Carter,
News: Baby is found abandoned, Mob lynches President's attacker, Zoology Doubt about gorilla's pregnancy, Tense Argentina awaits Rockefeller visit, Blood ...
1969 - Gale Group | TDA
Jim Al-Khalili revisits Ibn al-Haytham's hugely influential study on its millennium.
Tópico(s): History of Science and Medicine
2015 - Nature Portfolio | Nature
Katherine J. Mack, Karl Kruszelnicki, Lisa Randall, Jessica Wade, Jim Al-Khalili, Vlatko Vedral,
... She can be found on Twitter as @jesswade. Jim Al-Khalili, FRS, is a theoretical physicist, author and broadcaster. ...
Tópico(s): Media Influence and Health
2020 - Nature Portfolio | Nature Reviews Physics
I. J. Thompson, Jim Al-Khalili, J. A. Tostevin, J.M. Bang,
The quasielastic scattering of $^{11}\mathrm{Li}$ from $^{12}\mathrm{C}$ at 60 MeV/nucleon is calculated in a four-body Glauber approximation. Different $^{11}\mathrm{Li}$ ground-state wave functions are used, including those calculated using Faddeev three-body models. The calculated quasielastic cross sections, including the ${2}^{+}$ and ${3}^{\mathrm{\ensuremath{-}}}$ states of $^{12}\mathrm{C}$ in a distorted wave Born approximation, reproduce the experimental data over most of the angular range, the differences ...
Tópico(s): Atomic and Molecular Physics
1993 - American Institute of Physics | Physical Review C
Jim Al-Khalili, M. B. Barbaro, C. Wilkin,
A semi-phenomenological model is constructed for the 6Li(p eta )7Be reaction using cluster decomposition models for the 6Li and 7Be nuclei. Wavefunctions derived from potential model descriptions of these two nuclei give rise to form factors which are too small to fit the new experimental data. On the other hand, form factors deduced from experimental data on the analogous 6Li(p, pi +)7Li and 6Li(d,p)7Li single-nucleon transfer reactions at high momentum transfers give a plausible description.
Tópico(s): Astronomical and nuclear sciences
1993 - IOP Publishing | Journal of Physics G Nuclear and Particle Physics
Jim Al-Khalili, R. C. Johnson,
A parameter-free Glauber model calculation for deuteron-nucleus elastic scattering is carried out with full spin-dependence, which takes as its starting point the Dirac optical model for the underlying nucleon-nucleus potentials. The calculation includes effects due to the breakup of the deuteron to both triplet and singlet spin intermediate states. The observables for the reaction 58Ni(d, d) at 400 and 700 MeV are calculated and found to reproduce the experimental data quite well.
Tópico(s): Rare-earth and actinide compounds
1992 - Elsevier BV | Nuclear Physics A
Johnjoe McFadden, Jim Al-Khalili,
Tópico(s): Evolution and Genetic Dynamics
1999 - Elsevier BV | Biosystems
J. M. Brooke, Jim Al-Khalili, J. A. Tostevin,
Calculations which improve upon the eikonal model description of the scattering of loosely bound n-cluster composite nuclei at low and medium energies are studied. Each cluster-target eikonal phase shift is replaced by the continuation of the corresponding exact partial wave phase shift to noninteger angular momenta. Comparisons with fully quantum mechanical calculations for two-body projectiles show that this yields an accurate practical alternative to few-body adiabatic model calculations. Calculations ...
Tópico(s): Astronomical and nuclear sciences
1999 - American Institute of Physics | Physical Review C
J. A. Tostevin, Jim Al-Khalili,
Few-body Glauber theory calculations of reaction cross sections for the proposed single neutron halo nucleus ${}^{19}\mathrm{C}$ are presented for an incident energy of 960 MeV/nucleon on a ${}^{12}\mathrm{C}$ target. The calculated reaction cross sections are shown to be significantly smaller than those obtained using the optical limit approximation to the Glauber theory elastic profile function. The implications of these differences upon the deduced size and structure of the extended ${}^{19}\mathrm{C}$ ground ...
Tópico(s): Nuclear Physics and Applications
1999 - American Institute of Physics | Physical Review C
Jim Al-Khalili, J. A. Tostevin,
We present a theoretical analysis of recently published experimental data for the elastic scattering of protons from the helium isotopes ${}^{6}\mathrm{He}$ and ${}^{8}\mathrm{He}$ at energies near 700 MeV per nucleon. The analysis treats the few-body degrees of freedom of these light neutron-rich nuclei explicitly and is developed in terms of three- and five-body wave functions for ${}^{6}\mathrm{He}$ and ${}^{8}\mathrm{He}$, respectively. Comparisons of calculations with the data show that the sizes of the He nuclei ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1998 - American Institute of Physics | Physical Review C
J. A. Tostevin, R. C. Johnson, Jim Al-Khalili,
Total reaction cross section and elastic scattering angular distribution calculations are discussed for composite (halo) nuclei with well-developed core and valence particle structures. We review the basis of few-body calculations of reaction cross sections and use a simple binary cluster model to clarify the inadequacy of optical limit Glauber calculations for determining the sizes of correlated nuclear systems. An outstanding discrepancy in the case of the 6Li and 6He systems is discussed. We show ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1998 - Elsevier BV | Nuclear Physics A
J.A. Christley, Jim Al-Khalili, J. A. Tostevin, R. C. Johnson,
Elastic scattering of a projectile, composed of three clusters, from a spherical target is analysed using a four-body adiabatic model. The model is a generalisation of the three-body adiabatic model of Johnson and Soper. Calculations of the elastic scattering of 11Li from 12C are compared to both experimental data and the results of recent four-body eikonal model calculations.
Tópico(s): X-ray Spectroscopy and Fluorescence Analysis
1997 - Elsevier BV | Nuclear Physics A
R. C. Johnson, Jim Al-Khalili, J. A. Tostevin,
We show that under certain conditions a simple relationship exists between the elastic scattering of a composite halo nucleus and of its core from a stable target. The coupling of the elastic and projectile excitation channels is crucial to the analysis, which is particularly useful when the ratio of the halo to the core mass is small. In the case of ${}^{11}$Be elastic scattering the cross section relationship is quite well satisfied. For both ${}^{11}$Be and ${}^{19}$C our analysis reveals a significant sensitivity ...
Tópico(s): Nuclear Physics and Applications
1997 - American Physical Society | Physical Review Letters
Jim Al-Khalili, J. A. Tostevin, J. M. Brooke,
A physical prescription to improve the accuracy of few-body Glauber model calculations of reactions involving loosely bound projectiles is presented in which the eikonal phase shift function of each projectile constituent is modified to account for curvature of its trajectory. Noneikonal effects due to both nuclear and Coulomb interactions are treated on an equal footing. The proposed method is assessed quantitatively by comparison with full quantum mechanical calculations in the case of ${}^{11}$Be+${}^{ ...
Tópico(s): Atomic and Molecular Physics
1997 - American Institute of Physics | Physical Review C
J. A. Tostevin, Jim Al-Khalili,
We present quantitative reaction cross section calculations for halo nuclei at high energy which retain the essential few-body correlations in such structures. Inclusion of these correlations leads to larger deduced halo radii. For three-body (n+n+core) projectiles, cross section measurements determine the rms hyperradius of the system and, given the core nucleus size, the projectile matter radius. The importance of finite range effects are estimated in the case of the lightest two-neutron-halo system ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1997 - Elsevier BV | Nuclear Physics A
Jim Al-Khalili, J. A. Tostevin, I. J. Thompson,
The root mean square matter radii of halo nuclei provide a basic measure in constructing, constraining, and assessing theoretical models of halo structures. We consider corrections to static density (optical limit) Glauber model calculations of reaction cross sections of such nuclei at high energy giving careful consideration to their intrinsic few-body structure and the adiabatic nature of the halo nucleus-target interaction. We take as important examples the loosely bound two- and three-body systems $^{ ...
Tópico(s): Advanced Chemical Physics Studies
1996 - American Institute of Physics | Physical Review C
... B978-0-12-814371-1.16001-1Johnjoe McFadden, Jim Al-Khalili The origins of quantum biology, Proceedings of the ...
Tópico(s): Philosophy and History of Science
1996 - University of Chicago Press | Isis
M. P. Bush, Jim Al-Khalili, J. A. Tostevin, R. C. Johnson,
Measurements of reaction cross sections are routinely used to deduce effective nuclear root mean square (rms) radii by comparison with theoretical model predictions. Cross sections calculated using the optical limit Glauber model depend strongly on the rms radius of the density assumed for the projectile nucleus. We investigate such calculations by assuming a range of projectile density distributions. We show that calculated $^{11}\mathrm{Li}$-target cross sections at fixed rms radii retain a significant ...
Tópico(s): Nuclear Physics and Applications
1996 - American Institute of Physics | Physical Review C
Jim Al-Khalili, D. Cortina‐Gil, P. Roussel‐Chomaz, N. Alamanos, J. Barrette, W. Mittig, F. Auger, Y. Blumenfeld, J. M. Casandjian, M. Chartier, V. Fékou-Youmbi, B. Fernández, Nathalie Frascaria‐Lacoste, A. Gillibert, H. Laurent, A. Lépine‐Szily, N. A. Orr, V. Pascalon, J.A. Scarpaci, J.L. Sida, Tiina Suomijärvi,
Tópico(s): Quantum Chromodynamics and Particle Interactions
1996 - Elsevier BV | Physics Letters B
M. Zahar, M. Belbot, J.J. Kolata, K. Lamkin, D. J. Morrissey, B. M. Sherrill, M. Lewitowicz, A. H. Wuosmaa, Jim Al-Khalili, J. A. Tostevin, I. J. Thompson,
The quasielastic scattering of $^{9}\mathrm{Li}$ on a $^{12}\mathrm{C}$ target has been measured at an incident energy of 540 MeV. The new experimental data are used to extract an effective interaction for $^{9}\mathrm{Li}$ + $^{12}\mathrm{C}$ scattering. The uncertainty in this interaction was previously a major obstacle to extracting information on the structure of $^{11}\mathrm{Li}$ from existing $^{11}\mathrm{Li}$ +${\mathrm{}}^{12}$C quasielastic-scattering data. \textcopyright{} 1996 The American Physical Society.
Tópico(s): Atomic and Molecular Physics
1996 - American Institute of Physics | Physical Review C
Jim Al-Khalili, J. A. Tostevin,
We reexamine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using ${}^{11}$Li, ${}^{11}$Be, and ${}^{8}$B as examples we show that data require significantly larger matter radii than previously reported. The revised value for ${}^{11}$Li of 3.55 fm is consistent with three-body models with significant $1s$- ...
Tópico(s): Atomic and Molecular Physics
1996 - American Physical Society | Physical Review Letters
The effect of coupling to the projectile breakup channel on 11Li elastic scattering from 12C at 57.9 MeV/nucleon and 28Si at 29 MeV/nucleon is investigated. Correlated 11Li wave functions based on Faddeev three-body models are used within a four-body (9Li+n+n+A) Glauber scattering model. The single-folded potential for 11Li is calculated and used to isolate the part of the scattering amplitude from coupling to breakup states. It is found that the breakup has a large effect on the elastic cross sections ...
Tópico(s): Astronomical and nuclear sciences
1995 - Elsevier BV | Nuclear Physics A
S. Ait-Tahar, Jim Al-Khalili, Youcef Nedjadi,
It is the purpose of this paper to present the first relativistic description of alpha-nucleus elastic scattering using an optical model with the Duffin-Kemmer-Petiau (DKP) equation as the applicable wave equation. The DKP optical model potentials that are used are obtained by a folding procedure involving phenomenological Lorentz scalar and vector Dirac nucleon-nucleus potentials. In order to probe the DKP description of the alpha-nucleus interaction, we consider the elastic α-scattering on a range ...
Tópico(s): High-pressure geophysics and materials
1995 - Elsevier BV | Nuclear Physics A
Jim Al-Khalili, I. J. Thompson, J. A. Tostevin,
An eikonal model is presented and evaluated for the elastic scattering of 11Li from target nuclei. The 11Li is treated as a 9Li+n+n three-body system interacting with the target through two-body 9Li- and neutron-target interactions. A careful quantitative investigation of the sensitivity of the calculated elastic-scattering cross section to the required theoretical inputs, the neutron and 9Li-target potentials and the assumed structure of the 11Li, is presented. Since the structure of the 11Li halo ...
Tópico(s): Nuclear Physics and Applications
1995 - Elsevier BV | Nuclear Physics A
We present an analysis of the Beam–Target double polarization asymmetry for the photoproduction of Θ+ in γn→Θ+K−. We show that this quantity can serve as a filter for the determination of the Θ+'s spin-parity assignment near threshold. It is highly selective between 1/2+ and 1/2− configurations due to dynamical reasons.
Tópico(s): Atomic and Subatomic Physics Research
2004 - Elsevier BV | Physics Letters B
F. Sarazin, Jim Al-Khalili, G. C. Ball, G. Hackman, P. M. Walker, R. A. E. Austin, B. Eshpeter, P. Finlay, P. E. Garrett, G. F. Grinyer, K. A. Koopmans, W. D. Kulp, J. R. Leslie, D. Melconian, C. J. Osborne, M. A. Schumaker, H. C. Scraggs, J. von Schwarzenberg, M. B. Smith, C. E. Svensson, J. C. Waddington, John L. Wood,
The $\ensuremath{\beta}$ decay of $^{11}\mathrm{Li}$ has been investigated at TRIUMF-ISAC using a high-efficiency array of Compton suppressed $\mathrm{HPGe}$ detectors. From a line-shape analysis of the Doppler-broadened peaks observed in the $^{10}\mathrm{Be}$ $\ensuremath{\gamma}$ spectrum, both the half-lives of states in $^{10}\mathrm{Be}$ and the energies of the $\ensuremath{\beta}$-delayed neutrons feeding those states were obtained. Furthermore, it was possible to determine the excitation energies of the ...
Tópico(s): Nuclear Physics and Applications
2004 - American Institute of Physics | Physical Review C
We review here theoretical models for describing various types of reactions involving light nuclei on the driplines. Structure features to be extracted from the analysis of such reaction data, as well as those that need to be incorporated in the reaction models for an adequate description of the processes, are also under focus. The major unsolved theoretical issues are discussed, along with some suggestions for future directions of the field.
Tópico(s): Advanced Chemical Physics Studies
2003 - IOP Publishing | Journal of Physics G Nuclear and Particle Physics
Q. Zhao, Jim Al-Khalili, Z.-P. Li, R. L. Workman,
We present a detailed quark-model study of pion photoproduction within the effective Lagrangian approach. Cross sections and single-polarization observables are investigated for the four charge channels, $\gamma p\to \pi^+ n$, $\gamma n\to \pi^- p$, $\gamma p\to \pi^0 p$, and $\gamma n\to \pi^0 n$. Leaving the $\pi N\Delta$ coupling strength to be a free parameter, we obtain a reasonably consistent description of these four channels from threshold to the first resonance region. Within this effective Lagrangian ...
Tópico(s): High-Energy Particle Collisions Research
2002 - American Institute of Physics | Physical Review C
Q. Zhao, Jim Al-Khalili, C. Bennhold,
The photoproduction of ${K}^{*}$ vector mesons is investigated in a quark model with an effective Lagrangian. Including both baryon resonance excitations and t-channel exchanges, observables for the reactions $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}{K}^{*0}{\ensuremath{\Sigma}}^{+}$ and $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}{K}^{*+}{\ensuremath{\Sigma}}^{0}$ are predicted, using the SU(3)-flavor-blind assumption of nonperturbative QCD.
Tópico(s): High-Energy Particle Collisions Research
2001 - American Institute of Physics | Physical Review C
Q. Zhao, B. Saghaï, Jim Al-Khalili,
We examine the non-diffractive mechanisms in the φ-meson photoproduction from threshold up to a few GeV using an effective Lagrangian in a constituent quark model. The new data from CLAS at large angles can be consistently accounted for in terms of s- and u-channel processes. Isotopic effects arising from the reactions γp→φp and γn→φn, are investigated by comparing the cross sections and polarized beam asymmetries. Our result highlights an experimental means of studying non-diffractive mechanisms ...
Tópico(s): Particle physics theoretical and experimental studies
2001 - Elsevier BV | Physics Letters B