Showing papers on "Elementary particle published in 2005"
TL;DR: In this paper, the authors discuss the possibility of finding evidence for a spontaneously broken hidden sector through renormalizable interactions of the Standard Model Higgs boson with a Higgs Boson of the hidden sector.
Abstract: Little experimental data bears on the question of whether there is a spontaneously broken hidden sector that has no Standard Model quantum numbers. Here we discuss the prospects of finding evidence for such a hidden sector through renormalizable interactions of the Standard Model Higgs boson with a Higgs boson of the hidden sector. We find that the lightest Higgs boson in this scenario has smaller rates in standard detection channels, and it can have a sizeable invisible final state branching fraction. Details of the hidden sector determine whether the overall width of the lightest state is smaller or larger than the Standard Model width. We compute observable rates, total widths and invisible decay branching fractions within the general framework. We also introduce the 'A-Higgs Model', which corresponds to the limit of a hidden sector Higgs boson weakly mixing with the Standard Model Higgs boson. This model has only one free parameter in addition to the mass of the light Higgs state and it illustrates most of the generic phenomenology issues, thereby enabling it to be a good benchmark theory for collider searches. We end by presenting an analogous supersymmetry model with similar phenomenology, which involves hidden sector Higgs bosons interactingmore » with MSSM Higgs bosons through D-terms.« less
309 citations
TL;DR: A multiplicative factor of 2 p v was omitted from the charged Goldstone boson interaction term on the last line of Eq. (87) as discussed by the authors, and the correct expressions read: Z 1 Z a bc d ^ v a ^ v b ^ v c ^ v d ; Z 2 Z a c d ^ w a ^ w b ^ w c ^ w d
Abstract: A multiplicative factor of 2 p v was omitted from the charged Goldstone boson (G ) interaction term on the last line of Eq. (87). The last line of this equation should read In Eq. (B5), the last ^ w b should be removed from Z 2. The correct expressions read: Z 1 Z a bc d ^ v a ^ v b ^ v c ^ v d ; Z 2 Z a bc d ^ w a ^ w b ^ w c ^ w d
168 citations
TL;DR: The string-net picture has been used to make artificial photons, artificial electrons, and artificial quarks and gluons in condensed-matter systems as discussed by the authors, and it has been shown that these new phases of matter have the unusual property that their collective excitations are gauge bosons and fermions.
Abstract: Recent advances in condensed-matter theory have revealed that new and exotic phases of matter can exist in spin models (or more precisely, local bosonic models) via a simple physical mechanism, known as ``string-net condensation.'' These new phases of matter have the unusual property that their collective excitations are gauge bosons and fermions. In some cases, the collective excitations can behave just like the photons, electrons, gluons, and quarks in our vacuum. This suggests that photons, electrons, and other elementary particles may have a unified origin---string-net condensation in our vacuum. In addition, the string-net picture indicates how to make artificial photons, artificial electrons, and artificial quarks and gluons in condensed-matter systems.
152 citations
TL;DR: In this article, the authors considered the flavor symmetry of the neutrino mass matrix and proposed a see-saw mechanism to generate a light mass matrix with an approximate flavor symmetry.
Abstract: We consider the flavor symmetry $L_\mu - L_\tau$
for the neutrino mass matrix. The most general neutrino mass matrix conserving $L_\mu - L_\tau$
predicts quasi-degenerate neutrino masses with one maximal and two zero mixing angles. The presence of $L_\mu - L_\tau$
can also be motivated by the near-bimaximal form of the neutrino mixing matrix. Furthermore, it is a special case of $\mu \tau$
symmetric mass matrices. Breaking the flavor symmetry by adding a small flavor-blind term to the neutrino mass matrix and/or by applying radiative corrections is shown to reproduce the observed neutrino oscillation phenomenology. Both the normal and inverted mass ordering can be accommodated within this scheme. Moderate cancellation for neutrinoless double beta decay is expected. The observables |U
e3|2 and $\vert 1/2 - \sin^2\theta_{23}\vert$
are proportional to the inverse of the fourth power of the common neutrino mass scale. We comment on whether the atmospheric neutrino mixing is expected to lie above or below $\pi/4$
. We finally present a model based on the see-saw mechanism which generates a light neutrino mass matrix with an (approximate) $L_\mu - L_\tau$
flavor symmetry. This is a minimal model with just one standard Higgs doublet and three heavy right-handed neutrinos. It needs only small values for the soft $L_\mu - L_\tau$
breaking terms to reproduce the phenomenological viable mass textures analyzed.
107 citations
TL;DR: In this article, the authors discuss possible searches for the new particles predicted by Little Higgs Models at the LHC using a simulation of the ATLAS detector and demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.
Abstract: We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.
99 citations
TL;DR: In this paper, a new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework, in which two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number.
Abstract: A new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework. Two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number The novel mathematical theory of almost-commutative geometry [1] wishes to unify gauge models with gravity. In this scenario two new heavy (m_L>100GeV), oppositely double charged leptons (A,C),(A with charge -2 and C with charge +2), are born with no twin quark companions. The model naturally involves a new U(1) gauge interaction, possessed only by the AC-leptons and providing a Coulomblike attraction between them. AC-leptons posses electro-magnetic as well as Z-boson interaction and, according to the charge chosen for the new U(1) gauge interaction, a new "invisible light" interaction. Their final cosmic relics are bounded into "neutral" stable atoms (AC) forming the mysterious cold dark matter, in the spirit of the Glashow's Sinister model. An (AC) state is reached in the early Universe along a tail of a few secondary frozen exotic components. They should be now here somehow hidden in the surrounding matter. The two main secondary manifest relics are C (mostly hidden in a neutral (Cee) "anomalous helium" atom, at a 10-8 ratio) and a corresponding "ion" A bounded with an ordinary helium ion (4He); indeed the positive helium ions are able to attract and capture the free A fixing them into a neutral relic cage that has nuclear interaction (4HeA).
98 citations
TL;DR: In this paper, the electroweak charged and neutral currents in the non-commutative standard model (NCSM) and the Higgs and Yukawa parts of the NCSM action are discussed.
Abstract: We review the electroweak charged and neutral currents in the non-commutative standard model (NCSM) and compute the Higgs and Yukawa parts of the NCSM action. With the aim to make the NCSM accessible to phenomenological considerations, all relevant expressions are given in terms of physical fields, and Feynman rules are provided.
87 citations
TL;DR: In this article, the phase structure of zero temperature twisted mass lattice QCD is investigated and strong metastabilities in the plaquette observable in correspondence in which the untwisted quark mass assumes positive or negative values.
Abstract: The phase structure of zero temperature twisted mass lattice QCD is investigated. We find strong metastabilities in the plaquette observable in correspondence of which the untwisted quark mass assumes positive or negative values. We provide interpretations of this phenomenon in terms of chiral symmetry breaking and the effective potential model of Sharpe and Singleton.
79 citations
TL;DR: In this paper, an extension of the earlier work on electroweak currents and the Higgs sector in the standard model on non-commutative space-time, with strong interactions included, is presented.
Abstract: This paper is a direct extension of our earlier work on electroweak currents and the Higgs sector in the standard model on non-commutative space-time, now with strong interactions included. Apart from the non-commutative corrections to standard model strong interactions, several new interactions appear. The most interesting ones are gluonic interactions with the electroweak sector. They are elaborated here in detail and the Feynman rules for interactions up to ${\cal O}(g^2_s \theta)$
are provided.
76 citations
TL;DR: In this paper, the chiral Lagrangian couplings describing radiative corrections to weak semi-leptonic decays were studied and compared to the decay amplitude of a lepton, computed by Braaten and Li at one loop in the standard model.
Abstract: We focus on the chiral Lagrangian couplings describing radiative corrections to weak semi-leptonic decays and relate them to the decay amplitude of a lepton, computed by Braaten and Li at one loop in the standard model. For this purpose, we follow a two-step procedure. A first matching, from the standard model to Fermi theory, yields a relevant set of counterterms. The latter are related to chiral couplings thanks to a second matching, from Fermi theory to the chiral Lagrangian, which is performed using the spurion method. We show that the chiral couplings of physical relevance obey integral representations in a closed form, expressed in terms of QCD chiral correlators and vertex functions. We deduce exact relations among the couplings, as well as numerical estimates which go beyond the usual $\log(M_Z/M_\rho)$
approximation.
72 citations
TL;DR: In this paper, the authors give an explicit formula for the proton decay rate in the minimal renormalizable supersymmetric (SUSY) SO(10) model.
Abstract: We give an explicit formula for the proton decay rate in the minimal renormalizable supersymmetric (SUSY) SO(10) model. In this model, the Higgs fields consist of the 10 and $\mathbf{\overline{126}}$
SO(10) representations in the Yukawa interactions with matter and of the 10, $\mathbf{\overline{126}}$
, 126, and 210 representations in the Higgs potential. We present all the mass matrices for the Higgs fields contained in this minimal SUSY SO(10) model. Finally, we discuss the threshold effects of these Higgs fields on the gauge coupling unification.
CERN1
TL;DR: The complete set of two-loop electroweak corrections to the decay width of the Higgs boson into two photons is presented in this paper, where the contributions involving weak bosons and the top quark are computed in terms of an expansion in the external momentum.
TL;DR: In this paper, the authors review recent progress in studying in-medium modification of inter-quark forces at finite temperature in lattice QCD and discuss some applications to the problem of quarkonium binding in potential models.
Abstract: I review recent progress in studying in-medium modification of inter-quark forces at finite temperature in lattice QCD. Some applications to the problem of quarkonium binding in potential models are also discussed.
TL;DR: In this article, the authors considered the production of a e¯¯¯¯ + e¯¯ -pair by a high-energy photon in the field of a strong laser wave and derived a probability of this process for circularly or linearly polarized laser photons and for arbitrary polarization of all other particles.
Abstract: We consider production of a e
+ e
- pair by a high-energy photon in the field of a strong laser wave. A probability of this process for circularly or linearly polarized laser photons and for arbitrary polarization of all other particles is calculated. We obtain the complete set of functions which describe such a probability in a compact invariant form. Besides, we discuss in some detail the polarization effects in the kinematics relevant to the problem of $e\to \gamma$
conversion at $\gamma \gamma$
and ${\gamma e}$
colliders.
TL;DR: In this paper, the effect of changing the lattice action for the gluon field on the recently observed first order phase transition near zero quark mass is investigated by replacing the Wilson plaquette action by the DBW2 action.
Abstract: The effect of changing the lattice action for the gluon field on the recently observed [F. Farchioni, R. Frezzotti, K. Jansen, I. Montvay, G.C. Rossi, E. Scholz, A. Shindler, N. Ukita, C. Urbach, I. Wetzorke, Eur. Phys. J. C 39, 421 (2005); hep-lat/0406039] first order phase transition near zero quark mass is investigated by replacing the Wilson plaquette action by the DBW2 action. The lattice action for quarks is unchanged: it is in both cases the original Wilson action. It turns out that Wilson fermions with the DBW2 gauge action have a phase structure where the minimal pion mass and the jump of the average plaquette are decreased, when compared to Wilson fermions with Wilson plaquette action at similar values of the lattice spacing. Taking the DBW2 gauge action is advantageous also from the point of view of the computational costs of numerical simulations.
TL;DR: In this paper, the mixing between the states can be very large if the theory is CP-non-invariant, and some interesting experimental consequences are discussed for 2-Higgs doublet models.
Abstract: For large masses, the two heavy neutral Higgs bosons are nearly degenerate in many 2-Higgs doublet models, and particularly in supersymmetric models. In such a scenario the mixing between the states can be very large if the theory is CP-noninvariant. We analyze the formalism describing this configuration, and we point to some interesting experimental consequences.
TL;DR: In this article, a minimally supersymmetric extension of the standard model is proposed based on successive symmetry breaking of higher dimensional space with a maximal number of Killing's vectors, i.e. a maximally symmetric space.
Abstract: Data from relatively recent experiments with linear colliders relevant to the mass of the Higgs are used for orientation purposes to find a satisfactory theory for determining the number and the mass of these elusive particles. The proposed minimally supersymmetric extension of the standard model is based on successive symmetry breaking of higher dimensional space with a maximal number of Killing’s vectors, i.e. a maximally symmetric space. It is shown that the most likely scheme for the Higgs is that consistent with five physical Higgs particles, two charged and three neutrals. These five physical particles result from eight components that are most probably not directly observable. Important for the description of these particles is the mixing parameter tan β and the cross-section. Guided by the results obtained by fitting the scarce experimental data, the most likely range in which the mass of the Higgs particle may be found is between 160–180 GeV with 161.8 and 169.4 GeV being the most likely two values.
TL;DR: In this article, the production and decay of a coupled system of mixed neutral minimal supersymmetric extension of the Standard Model (MSSM) Higgs bosons in exclusive double-diffractive processes at the LHC, including nonvanishing $CP$ phases in the soft supersymmetry-breaking gaugino masses and third-generation trilinear squark couplings, were studied.
Abstract: We study the production and decay of a coupled system of mixed neutral minimal supersymmetric extension of the Standard Model (MSSM) Higgs bosons in exclusive double-diffractive processes at the LHC, including nonvanishing $CP$ phases in the soft supersymmetry-breaking gaugino masses and third-generation trilinear squark couplings. The three neutral Higgs bosons are naturally nearly degenerate, for large values of $\mathrm{tan} \ensuremath{\beta}$, when the charged Higgs boson weighs around 150 GeV. Large mixing between all three neutral Higgs bosons is possible when $CP$ is violated, a threeway mixing scenario which we also term trimixing. A resolution in the Higgs mass of $\ensuremath{\sim}1\text{ }\text{ }\mathrm{GeV}$, which may be achievable using the missing-mass method, would allow one to distinguish nearly degenerate Higgs bosons by studying the production lineshape. Measurements of the polarizations of the tau leptons coming from the Higgs-boson decays could offer a direct and observable signal of $CP$ violation in the Higgs sector.
TL;DR: In this article, the authors discuss the intriguing possibility that the answer is no, and particles are just points, and explain that, whatever the answer, there is a corresponding Bohm-type theory, and no experiment can ever decide between these theories.
Abstract: In Bohmian mechanics elementary particles exist objectively, as point particles moving according to a law determined by a wavefunction. In this context, questions as to whether the particles of a certain species are real---questions such as, Do photons exist? Electrons? Or just the quarks?---have a clear meaning. We explain that, whatever the answer, there is a corresponding Bohm-type theory, and no experiment can ever decide between these theories. Another question that has a clear meaning is whether particles are intrinsically distinguishable, i.e., whether particle world lines have labels indicating the species. We discuss the intriguing possibility that the answer is no, and particles are points---just points.
Posted Content•
29 Nov 2005
TL;DR: In this article, a new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework, in which two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number.
Abstract: A new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework. Two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number The novel mathematical theory of almost-commutative geometry [1] wishes to unify gauge models with gravity. In this scenario two new heavy (m_L>100GeV), oppositely double charged leptons (A,C),(A with charge -2 and C with charge +2), are born with no twin quark companions. The model naturally involves a new U(1) gauge interaction, possessed only by the AC-leptons and providing a Coulomblike attraction between them. AC-leptons posses electro-magnetic as well as Z-boson interaction and, according to the charge chosen for the new U(1) gauge interaction, a new "invisible light" interaction. Their final cosmic relics are bounded into "neutral" stable atoms (AC) forming the mysterious cold dark matter, in the spirit of the Glashow's Sinister model. An (AC) state is reached in the early Universe along a tail of a few secondary frozen exotic components. They should be now here somehow hidden in the surrounding matter. The two main secondary manifest relics are C (mostly hidden in a neutral (Cee) "anomalous helium" atom, at a 10-8 ratio) and a corresponding "ion" A bounded with an ordinary helium ion (4He); indeed the positive helium ions are able to attract and capture the free A fixing them into a neutral relic cage that has nuclear interaction (4HeA).
TL;DR: In this paper, the authors considered the Higgs boson production at high energy hadron colliders in the framework of the kT-factorization approach and focused on the dominant gluon-gluon fusion subprocess.
Abstract: We consider the Higgs boson production at high energy hadron colliders in the framework of the kT-factorization approach. The attention is focused on the dominant gluon-gluon fusion subprocess. We calculate the total cross section and transverse momentum distributions of the inclusive Higgs production using unintegrated gluon distributions in a proton obtained from the full CCFM evolution equation. We show that kT-factorization gives a possibility to investigate the associated Higgs boson and jets production. We calculate the transverse momentum distributions and study the Higgs-jet and jet-jet azimuthal correlations in the Higgs + one or two jet production processes. We demonstrate the importance of the higher-order corrections within the kT-factorization approach. These corrections should be developed and taken into account in the future applications.
TL;DR: In this article, the authors give a short outline of some interesting relations between sphere packing in higher dimensional spaces, the theory of P-Brane and the number of elementary particles in the standard model.
Abstract: The paper gives a short outline of some interesting relations between sphere packing in higher dimensional spaces, the theory of P-Brane and the number of elementary particles in the standard model. In particular we show that the 336 independent components of the Riemann curvature tensor may be represented by the contact points of 336 nine-dimensional spheres with a single central sphere embedded in 10 dimensions. Subsequently we show that the number of states in the 11-dimensional P-Brane super gravity, namely 528 may be found from the number of the contact points by scale transformation involving the seven-dimensional sphere and 11-dimensional M theory. Finally by eliminating shadow particles and using Kappa-like invariance, the theoretical number of elementary particles to be expected at an energy scale close to that of electro weak unification is found to be N ( SM ) = [ ( 336 ) ( 11 / 7 ) ] / 8 = 66 . Considering that there are at present only 60 experimentally confirmed particles, the result implies that there are some 6 particles still missing.
TL;DR: The theory of internal supersymmetry was first introduced by Ne'eman and Fairlie independently in 1979 and its various developments since then including applications and predictions of the theory to elementary particle physics as mentioned in this paper.
TL;DR: In this article, the relativistic wave equation for vector bosons in the expanding universe is exactly solved and it is shown that the current of the vectors in this background is rapidly oscillating in early time.
Abstract: We exactly solve the relativistic wave equation for vector bosons in the expanding universe and show that the current of the vector bosons in this background is rapidly oscillating in early time. Additionally, we derive the solutions of the Proca equation from the solutions of the Duffin-Kemmer-Petiau (DKP) equations in the same background and obtain the massless-particle, photon, solutions by taking the $m^{2}\rightarrow 0$
limit of these solutions. PACS. 03.65.Pm, 04.60.-m, 98.80.Cq
Journal Article•
[...]
TL;DR: In this article, the authors present a survey of the state-of-the-art work in the field of computer graphics and show that the majority of them are based on the same set of concepts as ours.
Abstract: A. Bozek, M. Rozanska, I. Adachi, H. Aihara, K. Arinstein, V. Aulchenko, T. Aushev, T. Aziz, A.M. Bakich, V. Bhardwaj, M. Bischofberger, A. Bondar, M. Bračko, T. E. Browder, Y. Chao, A. Chen, B.G. Cheon, I.-S. Cho, K.-S. Choi, Y. Choi, J. Dalseno, Z. Doležal, Z. Drásal, A. Drutskoy, W. Dungel, S. Eidelman, P. Goldenzweig, B. Golob, H. Ha, K. Hara, Y. Hasegawa, H. Hayashii, T. Higuchi, Y. Horii, Y. Hoshi, W.-S. Hou, H. J. Hyun, T. Iijima, K. Inami, M. Iwabuchi, Y. Iwasaki, N. J. Joshi, J. H. Kang, P. Kapusta, H. Kawai, T. Kawasaki, H. Kichimi, C. Kiesling, H. O. Kim, J. H. Kim, M. J. Kim, S. K. Kim, Y. J. Kim, B. R. Ko, S. Korpar, P. Križan, P. Krokovny, T. Kuhr, T. Kumita, A. Kuzmin, Y.-J. Kwon, S.-H. Kyeong, M. J. Lee, S.-H. Lee, J. Li, D. Liventsev, R. Louvot, A. Matyja, S. McOnie, H. Miyata, Y. Miyazaki, R. Mizuk, G. B. Mohanty, E. Nakano, M. Nakao, H. Nakazawa, S. Neubauer, S. Nishida, O. Nitoh, T. Nozaki, S. Ogawa, T. Ohshima, S. Okuno, S. L. Olsen, W. Ostrowicz, P. Pakhlov, G. Pakhlova, C.W. Park, H.K. Park, R. Pestotnik, M. Petrič, L. E. Piilonen, H. Sahoo, Y. Sakai, O. Schneider, J. Schümann, C. Schwanda, A. J. Schwartz, K. Senyo, J.-G. Shiu, B. Shwartz, R. Sinha, P. Smerkol, A. Sokolov, E. Solovieva, M. Starič, J. Stypula, T. Sumiyoshi, G.N. Taylor, Y. Teramoto, I. Tikhomirov, K. Trabelsi, S. Uehara, Y. Unno, S. Uno, G. Varner, K. E. Varvell, K. Vervink, C. H. Wang, M.-Z. Wang, P. Wang, Y. Watanabe, R. Wedd, E. Won, B. D. Yabsley, Y. Yamashita, V. Zhulanov, T. Zivko, and A. Zupanc
TL;DR: In this article, Luscher's finite size mass shift formula in a periodic finite volume, involving forward scattering amplitudes in the infinite volume, is revisited for the two stable distinguishable particle system.
TL;DR: In this article, the masses and decay constants of light pseudoscalar and scalar mesons within the QCD sum rules method are briefly reviewed and the predictions are based on the 1/Nc-supported model spectra, which consist of an infinite number of infinitely narrow resonances.
Abstract: The calculations of masses and decay constants of the radial excitations of light pseudoscalar and scalar mesons within the QCD sum rules method are briefly reviewed. The predictions are based on the 1/Nc-supported model spectra, which consist of an infinite number of infinitely narrow resonances, and on the assumption that the ground states of light scalar mesons may be considered as \(\bar qq\)-bound states. The results of the studies are compared with the existing experimental data and with the predictions of other theoretical approaches.
TL;DR: In this article, the authors investigated the possibility of distinguishing between the standard model higgs boson and the lightest Higgs boson in split supersymmetry, and showed that the best way to distinguish between these two HCs is through the decay into two photons.
Abstract: We investigate the possibility of distinguishing between the standard model higgs boson and the lightest Higgs boson in split supersymmetry. We point out that the best way to distinguish between these two Higgs bosons is through the decay into two photons. It is shown that there are large differences of several per cent between the predictions for Γ(h → γγ) in the two models, making possible the discrimination in future photon–photon colliders. Once the charginos are discovered in the next generation of collider experiments, the well-defined predictions for the Higgs decay into two photons will become a cross check to identify the light Higgs boson in split supersymmetry.
TL;DR: In this article, the authors show that CDM and DE can arise entirely from the standard principles of strong interaction physics and quantum entanglement, without the need for any adjustable parameters.