1994-01-01
Bosonization is a useful technique for studying systems of interacting fermions in low dimensions. It has applications in both particle and condensed matter physics.This book contains reprints of papers on the method as used in these fields. The papers range from the classic work of Tomonaga in the 1950's on one-dimensional electron gases, through the discovery of fermionic solitons in the 1970's, to integrable systems and bosonization on Riemann surfaces. A four-chapter pedagogical introduction by the editor should make the book accessible to graduate students and experienced researchers alik
Interference of composite bosons
Brougham, Thomas; Barnett, Stephen M.; Jex, Igor
2010-01-01
We investigate multi-boson interference. A Hamiltonian is presented that treats pairs of bosons as a single composite boson. This Hamiltonian allows two pairs of bosons to interact as if they were two single composite bosons. We show that this leads to the composite bosons exhibiting novel interference effects such as Hong-Ou-Mandel interference. We then investigate generalizations of the formalism to the case of interference between two general composite bosons. Finally, we show how one can ...
Tichy, Malte C.; Bouvrier, P. Alexander; Mølmer, Klaus
2013-01-01
Composite bosons made of two bosonic constituents exhibit deviations from ideal bosonic behavior due to their substructure. This deviation is reflected by the normalization ratio of the quantum state of N composites. We find a set of saturable, efficiently evaluable bounds for this indicator, which...... quantifies the bosonic behavior of composites via the entanglement of their constituents. We predict an abrupt transition between ordinary and exaggerated bosonic behavior in a condensate of two-boson composites....
Veltman, Martinus J. G.
1986-01-01
Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)
Higgs boson : production and decays into bosons
Escalier, Marc; The ATLAS collaboration
2016-01-01
The results on the Higgs boson with decay channels into bosons from the ATLAS and CMS experiments at LHC Run 1 and early Run 2 are reviewed in the context of the Standard Model. : observation of a signal, measurement of mass, width, spin, cross-sections, search for decay channels and production modes, Higgs couplings to various particles.
Bosonic behavior of entangled fermions
C. Tichy, Malte; Alexander Bouvrie, Peter; Mølmer, Klaus
2012-01-01
Two bound, entangled fermions form a composite boson, which can be treated as an elementary boson as long as the Pauli principle does not affect the behavior of many such composite bosons. The departure of ideal bosonic behavior is quantified by the normalization ratio of multi-composite-boson st......Two bound, entangled fermions form a composite boson, which can be treated as an elementary boson as long as the Pauli principle does not affect the behavior of many such composite bosons. The departure of ideal bosonic behavior is quantified by the normalization ratio of multi...
Taratuta, Rostislav
2015-01-01
The main purpose of this paper is to introduce the new bosonic mechanism and newtreatment of dark energy. The bosonic mechanism focuses on obtaining masses by gauge bosonswithout assuming the existence of Higgs boson. The hypothesis on dark energy as the energy ofa postulated dark field was made and a combined gravitational-dark field was introduced. This fieldis the key to a specified approach and allows addressing the fundamental starting points of the mechanism.i. Complex scalar field is i...
Liew, T. C. H.; Glazov, M. M.; Kavokin, K. V.; Shelykh, I. A.; Kaliteevski, M A; Kavokin, A.V.
2012-01-01
We propose a concept of a quantum cascade laser based on transitions of bosonic quasiparticles (excitons and exciton-polaritons) in a parabolic potential trap in a semiconductor microcavity. This laser would emit terahertz radiation due to bosonic stimulation of excitonic transitions. Dynamics of a bosonic cascade is strongly different from the dynamics of a conventional fermionic cascade laser. We show that populations of excitonic ladders are parity-dependent and quantized if the laser oper...
2008-01-01
Quantum physicists think they know the answer. Probabilistic calculations reveal than the data provided by previous experiments has been miscalculated and that the Higgs boson has in fact been discovered. Weird! The Higgs boson is the only particle predicted by the Standard Model that hasn't been discovered yet.
Pimenta, Jean Jûnio Mendes; Natti, Érica Regina Takano; Natti, Paulo Laerte
2013-01-01
The Higgs boson was predicted in 1964 by British physicist Peter Higgs. The Higgs is the key to explain the origin of the mass of other elementary particles of Nature. However, only with the coming into operation of the LHC, in 2008, there were technological conditions to search for the Higgs boson. Recently, a major international effort conducted at CERN, by means of ATLAS and CMS experiments, has enabled the observation of a new bosonic particle in the region of 125 GeVs. In this paper, by means of known mechanisms of symmetry breaking that occur in the BCS theory of superconductivity and in the theory of nuclear pairing, we discuss the Higgs mechanism in the Standard Model. Finally, we present the current state of research looking for the Higgs boson and the alternative theories and extensions of the Standard Model for the elementary particle physics. Keywords: Higgs boson, BCS theory, nuclear pairing, Higgs mechanism, Standard Model.
Kellerstein, M; Verbaarschot, J J M
2016-01-01
The behavior of quenched Dirac spectra of two-dimensional lattice QCD is consistent with spontaneous chiral symmetry breaking which is forbidden according to the Coleman-Mermin-Wagner theorem. One possible resolution of this paradox is that, because of the bosonic determinant in the partially quenched partition function, the conditions of this theorem are violated allowing for spontaneous symmetry breaking in two dimensions or less. This goes back to work by Niedermaier and Seiler on nonamenable symmetries of the hyperbolic spin chain and earlier work by two of the auhtors on bosonic partition functions at nonzero chemical potential. In this talk we discuss chiral symmetry breaking for the bosonic partition function of QCD at nonzero isospin chemical potential and a bosonic random matrix theory at imaginary chemical potential and compare the results with the fermionic counterpart. In both cases the chiral symmetry group of the bosonic partition function is noncompact.
Pimenta, Jean Jûnio Mendes; Belussi, Lucas Francisco Bosso; Natti, Érica Regina Takano; Natti, Paulo Laerte
2013-01-01
The Higgs boson was predicted in 1964 by British physicist Peter Higgs. The Higgs is the key to explain the origin of the mass of other elementary particles of Nature. However, only with the coming into operation of the LHC, in 2008, there were technological conditions to search for the Higgs boson. Recently, a major international effort conducted at CERN, by means of ATLAS and CMS experiments, has enabled the observation of a new bosonic particle in the region of 125 GeVs. In this paper, by ...
Photoproduction of leptophobic bosons
Fanelli, Cristiano
2016-01-01
We propose a search for photoproduction of leptophobic bosons that couple to quarks at the GlueX experiment at Jefferson Lab. We study in detail a new gauge boson that couples to baryon number $B$, and estimate that $\\gamma p \\to p B$ will provide the best sensitivity for $B$ masses above 0.5 GeV. This search will also provide sensitivity to other proposed dark-sector states that couple to quarks. Finally, our results motivate a similar search for $B$ boson electroproduction at the CLAS experiment.
Arkhipov, Alex
2011-01-01
We motivate and prove a version of the birthday paradox for $k$ identical bosons in $n$ possible modes. If the bosons are in the uniform mixed state, also called the maximally mixed quantum state, then we need $k \\sim \\sqrt{n}$ bosons to expect two in the same state, which is smaller by a factor of $\\sqrt{2}$ than in the case of distinguishable objects (boltzmannons). While the core result is elementary, we generalize the hypothesis and strengthen the conclusion in several ways. One side result is that boltzmannons with a randomly chosen multinomial distribution have the same birthday statistics as bosons. This last result is interesting as a quantum proof of a classical probability theorem; we also give a classical proof.
Barkhofen, Sonja; Bartley, Tim J.; Sansoni, Linda; Kruse, Regina; Hamilton, Craig S.; Jex, Igor; Silberhorn, Christine
2016-01-01
Sampling the distribution of bosons that have undergone a random unitary evolution is strongly believed to be a computationally hard problem. Key to outperforming classical simulations of this task is to increase both the number of input photons and the size of the network. We propose driven boson sampling, in which photons are input within the network itself, as a means to approach this goal. When using heralded single-photon sources based on parametric down-conversion, this approach offers ...
Stefania Pandolfi
2016-01-01
CERN celebrated the fourth anniversary of the historical Higgs boson announcement with special pizzas. 400 pizzas were served on Higgs pizza day in Restaurant 1 at CERN to celebrate the fourth anniversary of the announcement of the discovery of the Higgs Boson (Image: Maximilien Brice/ CERN) What do the Higgs boson and a pizza have in common? Pierluigi Paolucci, INFN and CMS collaboration member, together with INFN president Fernando Ferroni found out the answer one day in Naples: the pizza in front of them looked exactly like a Higgs boson event display. A special recipe was then created in collaboration with the chef of the historic “Ettore” pizzeria in the St. Lucia area of Naples, and two pizzas were designed to resemble two Higgs boson decay channel event displays. The “Higgs Boson Pizza Day” was held on Monday, 4 July 2016, on the fourth anniversary of the announcement of the discovery of the Higgs boso...
Cinzia De Melis
2016-01-01
Four years after the historic announcement of the Higgs boson discovery at CERN, a collaboration between INFN and CERN has declared 4 July 2016 as “Higgs Boson Pizza Day”. The idea was born in Naples, by Pierluigi Paolucci and INFN president Fernando Ferroni, who inspired the chef of the historic “Ettore” pizzeria in St. Lucia to create the Higgs boson pizza in time for the opening of a Art&Science exhibition on 15 September 2015 in Naples. The animation shows the culinary creation of a Higgs boson in form of a vegetarian and ham&salami pizza. Ham&Salami: A two asparagus (proton-proton) collision produces a spicy Higgs boson (chorizo) decaying into two high-energy salami (photon) clusters and a lot of charged (sliced ham) and neutral (olive) particles that are detected in the pizza (detector) entirely covered with mozzarella sensors. A two asparagus (proton-proton) collision produces a juicy Higgs boson (cherry tomato) decaying into four high-energy (charged) peppers producing a tasty sign...
Bosonic behavior of entangled fermions
Two bound, entangled fermions form a composite boson, which can be treated as an elementary boson as long as the Pauli principle remains irrelevant. The bosonic character of the composite is intimately linked to the entanglement of the fermions: Large entanglement implies good bosonic properties. The deviation from perfect bosonic behavior manifests itself in the statistical properties of the composites and in their collective interference. As a consequence, the counting statistics exhibited by composites allow one to infer the form of the two-fermion wave-function. Bosonic behavior can thus be used as a probe for the underlying structure of composite particles without directly accessing their constituents.
Marino, Eduardo
The electron, discovered by Thomson by the end of the nineteenth century, was the first experimentally observed particle. The Weyl fermion, though theoretically predicted since a long time, was observed in a condensed matter environment in an experiment reported only a few weeks ago. Is there any linking thread connecting the first and the last observed fermion (quasi)particles? The answer is positive. By generalizing the method known as bosonization, the first time in its full complete form, for a spacetime with 3+1 dimensions, we are able to show that both electrons and Weyl fermions can be expressed in terms of the same boson field, namely the Kalb-Ramond anti-symmetric tensor gauge field. The bosonized form of the Weyl chiral currents lead to the angle-dependent magneto-conductance behavior observed in these systems.
Liebling, Steven L
2012-01-01
The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called {\\em geons}, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name {\\em boson stars}. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.
Steven L. Liebling
2012-05-01
Full Text Available The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s, John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called geons, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name boson stars. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single Killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.
Tsekov, R
2016-01-01
Thermodynamically, bosons and fermions differ by their statistics only. A general entropy functional is proposed by superposition of entropic terms, typical for different quantum gases. The statistical properties of the corresponding Janus particles are derived by variation of the weight of the boson/fermion fraction. It is shown that di-bosons and anti-fermions separate in gas and liquid phases, while three-phase equilibrium appears for poly-boson/fermion Janus particles.
We study the phenomenology of Higgs bosons close to 126 GeV within the scale invariant unconstrained Next-to-Minimal Supersymmetric Standard Model (NMSSM), focusing on the regions of parameter space favoured by low fine-tuning considerations, namely stop masses of order 400 GeV to 1 TeV and an effective μ parameter between 100–200 GeV, with large (but perturbative) λ and low tanβ=2–4. We perform scans over the above parameter space, focusing on the observable Higgs cross sections into γγ, WW, ZZ, bb, ττ final states, and study the correlations between these observables. We show that the γγ signal strength may be enhanced up to a factor of about two not only due to the effect of singlet–doublet mixing, which occurs more often when the 126 GeV Higgs boson is the next-to-lightest CP-even one, but also due to light stops (and to a lesser extent light chargino and charged Higgs loops). There may be also smaller enhancements in the Higgs decay channels into WW, ZZ, correlated with the γγ enhancement. However there is no such correlation observed involving the Higgs decay channels into bb, ττ. The requirement of having perturbative couplings up to the GUT scale favours the interpretation of the 126 GeV Higgs boson as being the second lightest NMSSM CP-even state, which can decay into pairs of lighter neutralinos, CP-even or CP-odd Higgs bosons, leading to characteristic signatures of the NMSSM. In a non-negligible part of the parameter range the increase in the γγ rate is due to the superposition of rates from nearly degenerate Higgs bosons. Resolving these Higgs bosons would rule out the Standard Model, and provide evidence for the NMSSM
Anomalous gauge boson interactions
We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge-boson self interactions. If the energy scale of the new physics is ∼ 1 TeV, these low energy anomalous couplings are expected to be no larger than Ο(10-2). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed
This is the summary report of the Higgs Boson Working Group. We discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K → πH, η prime → ηH,Υ → Hγ and e+e- → ZH are examined with particular attention paid to theoretical uncertainties in the calculations. We also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields. 33 refs., 6 figs., 1 tab
Nonexotic Neutral Gauge Bosons
Appelquist, Thomas; Dobrescu, Bogdan A.; Hopper, Adam R.
2002-01-01
We study theoretical and experimental constraints on electroweak theories including a new color-singlet and electrically-neutral gauge boson. We first note that the electric charges of the observed fermions imply that any such Z' boson may be described by a gauge theory in which the Abelian gauge groups are the usual hypercharge along with another U(1) component in a kinetic-diagonal basis. Assuming that the observed quarks and leptons have generation-independent U(1) charges, and that no new...
This paper is the summary report of the Higgs Boson Working Group. The authors discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K → πH, η' → ηH, Υ → Hγ and e+e- → ZH are examined with particular attention paid to theoretical uncertainties in the calculations. The authors also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields
Bosonic variables in nuclear matters
It is shown that the boson theoretical interpretation of nuclear forces nessecitates the introduction of bosonic variables within the state function of nuclear matter. In this framework the 2-boson exchange plays a decisive role and calls for the introduction of special selfenergy diagrams. This generalized scheme is discussed with the help of a solvable field theoretical model. (orig.)
Intermediate mass Higgs boson(s)
Finding and understanding the spectrum of scalar bosons is the central problem of particle physics today. Considerable work has been done to learn how to study Standard Model heavy and obese Higgs bosons; simulations including the problems induced by standard model backgrounds are underway, and some results are reported elsewhere in these proceedings. The mass region MH Z/2 will be covered at SLC and LEP. LEPII will be able to extend this range to about 85 GeV. Above MH > 2MZ the search is easy for a Standard Model H degree at the SSC, though not so simple for the neutral scalars of a supersymmetric theory. The intermediate region, MZ/2 ≤ MH ≤ 2MZ is one of the most difficult mass regions to study, and it is the subject of this report. The authors concentrate on a neutral Standard Model scalar to be specific. The lightest scalar of a supersymmetric theory behaves very much like a Standard Model scalar for most ranges of parameters, so the results generally apply to that case as well, and for any form the scalar spectrum might take our results indicate how the analysis might go. Ultimately, to fully understand spontaneous symmetry breaking and the origin of mass, it will be necessary to find any intermediate mass scalar and to know in what mass ranges no scalars exist. Their analysis is only in progress, and their results reported here must be regarded as tentative
Jora, Renata
2009-01-01
We propose an electroweak model based on the identification of the Higgs with the dilaton. We show that it is possible in this context to have a massless Higgs boson at tree and one loop levels without contradicting the main experimental and theoretical constraints.
AUTHOR|(CDS)2077480; Müller, Katharina; Anderson, Jonathan
In this thesis several measurements of the $Z$ boson production cross section in the LHCb detector are presented. After an introduction with the description of the underlying theory; the detector and the properties of the collisions the machine provided to us in LHC run I in Chapter 1, in Chapter 2 the details of the $Z$ reconstruction in the $Z\\rightarrow\\mu^+\\mu^-$ final state is discussed. In Chapter 3 jets are added to the $Z$ bosons. Several aspects of jet reconstruction are presented and a cross section measurement for the associated production of $Z$ bosons with jets at $\\sqrt{s}=7$ TeV is presented for two transverse momentum thresholds of the jets. In Chapter 4 the capability of the LHCb detector to reconstruct charmed mesons is used to establish a $ZD^{0}$ and a $ZD^{+}$ signal and to measure the total cross section. In Chapter 5 the cross section of inclusive $Z$ boson production is measured at a low statistics sample of $3.3~\\text{pb}^{-1}$ at $\\sqrt{s}=2.76$ TeV.
Fermion-fermion and boson-boson amplitudes: surprising similarities
Dvoeglazov, Valeri V
2007-01-01
Amplitudes for fermion-fermion, boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the model is the Weinberg's 2(2j+1)-component formalism for describing a particle of spin j. The boson-boson amplitude is then compared with the two-fermion amplitude obtained long ago by Skachkov on the basis of the Hamiltonian formulation of quantum field theory on the mass hyperboloid, p_0^2 - p^2=M^2, proposed by Kadyshevsky. The parametrization of the amplitudes by means of the momentum transfer in the Lobachevsky space leads to same spin structures in the expressions of T-matrices for the fermion case and the boson case. However, certain differences are found. Possible physical applications are discussed.
Spring, Justin B; Humphreys, Peter C; Kolthammer, W Steven; Jin, Xian-Min; Barbieri, Marco; Datta, Animesh; Thomas-Peter, Nicholas; Langford, Nathan K; Kundys, Dmytro; Gates, James C; Smith, Brian J; Smith, Peter G R; Walmsley, Ian A
2013-01-01
While universal quantum computers ideally solve problems such as factoring integers exponentially more efficiently than classical machines, the formidable challenges in building such devices motivate the demonstration of simpler, problem-specific algorithms that still promise a quantum speedup. We construct a quantum boson sampling machine (QBSM) to sample the output distribution resulting from the nonclassical interference of photons in an integrated photonic circuit, a problem thought to be exponentially hard to solve classically. Unlike universal quantum computation, boson sampling merely requires indistinguishable photons, linear state evolution, and detectors. We benchmark our QBSM with three and four photons and analyze sources of sampling inaccuracy. Our studies pave the way to larger devices that could offer the first definitive quantum-enhanced computation.
Interacting boson approximation
Lectures notes on the Interacting Boson Approximation are given. Topics include: angular momentum tensors; properties of T/sub i//sup (n)/ matrices; T/sub i//sup (n)/ matrices as Clebsch-Gordan coefficients; construction of higher rank tensors; normalization: trace of products of two s-rank tensors; completeness relation; algebra of U(N); eigenvalue of the quadratic Casimir operator for U(3); general result for U(N); angular momentum content of U(3) representation; p-Boson model; Hamiltonian; quadrupole transitions; S,P Boson model; expectation value of dipole operator; S-D model: U(6); quadratic Casimir operator; an O(5) subgroup; an O(6) subgroup; properties of O(5) representations; quadratic Casimir operator; quadratic Casimir operator for U(6); decomposition via SU(5) chain; a special O(3) decomposition of SU(3); useful identities; a useful property of D/sub αβγ/(α,β,γ = 4-8) as coupling coefficients; explicit construction of T/sub x//sup (2)/ and d/sub αβγ/; D-coefficients; eigenstates of T3; and summary of T = 2 states
Boson stars with nonminimal coupling
Marunovic, Anja
2015-01-01
Boson stars coupled to Einstein's general relativity possess some features similar to gravastars, such as the anisotropy in principal pressures and relatively large compactness ($\\mu_{max} = 0.32$). However, no matter how large the self-interaction is, the ordinary boson star cannot obtain arbitrarily large compression and as such does not represent a good black hole mimicker. When the boson star is nonminimally coupled to gravity, the resulting configurations resemble more the dark energy stars then the ordinary boson stars, with compactness significantly larger then that in ordinary boson stars (if matter is not constrained with the energy conditions). The gravitationally bound system of a boson star and a global monopole represents a good black hole mimicker.
Boson star at finite temperature
Latifah, S; Mart, T
2014-01-01
By using a simple thermodynamical method we confirm the finding of Chavanis and Harko that stable Bose-Einstein condensate stars can form. However, by using a thermodynamically consistent boson equation of state, we obtain a less massive Bose-Einstein condensate star compared to the one predicted by Chavanis and Harko. We also obtain that the maximum mass of a boson star is insensitive to the change of matter temperature. However, the mass of boson star with relatively large radius depends significantly on the temperature of the boson matter.
Bosonization and Lie Group Structure
Ha, Yuan K
2015-01-01
We introduce a concise quantum operator formula for bosonization in which the Lie group structure appears in a natural way. The connection between fermions and bosons is found to be exactly the connection between Lie group elements and the group parameters. Bosonization is an extraordinary way of expressing the equation of motion of a complex fermion field in terms of a real scalar boson in two dimensions. All the properties of the fermion field theory are known to be preserved under this remarkable transformation with substantial simplification and elucidation of the original theory, much like Lie groups can be studied by their Lie algebras.
Moss, Ian G
2015-01-01
The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics from the electroweak phase transition one nanosecond after the big bang, on to the end of the present-day universe through vacuum decay. Higgs physics is wide-ranging, and gives an impetus to go beyond the Standard Models of particle physics and cosmology to explore the physics of ultra-high energies and quantum gravity.
Hartmann, Betti [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany); Kleihaus, Burkhard; Kunz, Jutta [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Schaffer, Isabell, E-mail: i.schaffer@jacobs-university.de [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany)
2012-07-24
We consider compact boson stars that arise for a V-shaped scalar field potential. They represent a one parameter family of solutions of the scaled Einstein-Gordon equations. We analyze the physical properties of these solutions and determine their domain of existence. Along their physically relevant branch emerging from the compact Q-ball solution, their mass increases with increasing radius. Employing arguments from catastrophe theory we argue that this branch is stable, until the maximal value of the mass is reached. There the mass and size are on the order of magnitude of the Schwarzschild limit, and thus the spiraling respectively oscillating behaviour, well known for compact stars, sets in.
Lykken, Joseph D.
1996-01-01
A broad class of supersymmetric extensions of the standard model predict a Z' vector boson whose mass is naturally in the range 250 GeV < M_Z' < 2 TeV. To avoid unacceptably large mixing with the Z, one requires either a discrete tuning of the U(1)' charges or a leptophobic Z'. Both cases are likely to arise as the low energy limits of heterotic string compactifications, but a survey of existing realistic string models provides no acceptable examples. A broken U(1)' leads to additional D-term...
Deformation quantization of bosonic strings
Deformation quantization of bosonic strings is considered. We show that the light-cone gauge is the most convenient classical description to perform the quantization of bosonic strings in the deformation quantization formalism. Similar to the field theory case, the oscillator variables greatly facilitates the analysis. The mass spectrum, propagators and the Virasoro algebra are finally described within this deformation quantization scheme. (author)
Hierarchy in Sampling Gaussian-correlated Bosons
Huh, Joonsuk
2016-01-01
Boson Sampling represents a class of physical processes potentially intractable for classical devices to simulate. The Gaussian extension of Boson Sampling remains a computationally hard problem, where the input state is a product of uncorrelated Gaussian modes. Besides, motivated by molecular spectroscopy, Vibronic Boson Sampling involves operations that can generate Gaussian correlation among different Boson modes. Therefore, Gaussian Boson Sampling is a special case of Vibronic Boson Sampling. However, this does not necessarily mean that Vibronic Boson Sampling is more complex than Gaussian Boson Sampling. Here we develop a hierarchical structure to show how the initial correlation in Vibronic Boson Sampling can be absorbed in Gaussian Boson Sampling with ancillary modes and in a scattershot fashion. Since every Gaussian state is associated with a thermal state, our result implies that every sampling problem in molecular vibronic transitions, at any temperature, can be simulated by Gaussian Boson Sampling ...
A Minimally Symmetric Higgs Boson
Low, Ian
2014-01-01
Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized SU(2)xU(1) electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal in all models where the Higgs arises as a pseudo-Nambu-Goldstone boson (PNGB). Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.
Bosonization and quantum hydrodynamics
Girish S Setlur
2006-03-01
It is shown that it is possible to bosonize fermions in any number of dimensions using the hydrodynamic variables, namely the velocity potential and density. The slow part of the Fermi field is defined irrespective of dimensionality and the commutators of this field with currents and densities are exponentiated using the velocity potential as conjugate to the density. An action in terms of these canonical bosonic variables is proposed that reproduces the correct current and density correlations. This formalism in one dimension is shown to be equivalent to the Tomonaga-Luttinger approach as it leads to the same propagator and exponents. We compute the one-particle properties of a spinless homogeneous Fermi system in two spatial dimensions with long-range gauge interactions and highlight the metal-insulator transition in the system. A general formula for the generating function of density correlations is derived that is valid beyond the random phase approximation. Finally, we write down a formula for the annihilation operator in momentum space directly in terms of number conserving products of Fermi fields.
Brunet, S
2014-01-01
ATLAS Higgs poster targeted to general public, explaining the Brout-Englert-Higgs mechanism and why it is important. It also explains the role of the Higgs Boson, how we look for it, the journey of the discovery and what comes after the discovery. Also available in French (http://cds.cern.ch/record/1697501). Don’t hesitate to use it in your institute’s corridors and in your outreach events! The poster is in A0 format. You can click on the image to download the high-quality .pdf version and print it at your favorite printshop. For any questions or comments you can contact atlas-outreach-coordination@cern.ch.
The discovery of the Z boson 7 years ago verified a key prediction of the unified theory of electromagnetic and weak forces. Today an experimental program is beginning at two electron-positron colliders to study the properties of the Z particle in great detail. The data accumulated will subject the unified theory to more rigorous tests and will probe with great sensitivity for new physics not encompassed by the existing standard model of the elementary particles and forces. Questions under study include the number of quark and lepton families, the mass of the still undiscovered top quark, and the search for the still unknown fifth force of nature required by the theory to generate the masses of the elementary particles. 48 refs., 3 figs., 1 tab
He, Hong-Jian
1998-08-01
We review the recent progress in studying the anomalous electroweak quartic gauge boson couplings (QGBCs) at the LHC and the next generation high energy e±e- linear colliders (LCs). The main focus is put onto the strong electroweak symmetry breaking scenario in which the non-decoupling guarantees sizable new physics effects for the QGBCs. After commenting upon the current low energy indirect bounds and summarizing the theoretical patterns of QGBCs predicted by the typical resonance/non-resonance models, we review our systematic model-independent analysis on bounding them via WW-fusion and WWZ/ZZZ-production. The interplay of the two production mechanisms and the important role of the beam-polarization at the LCs are emphasized. The same physics may be similarly and better studied at a multi-TeV muon collider with high luminosity.
This is a pedagogical introduction to the general technique of bosonization of one-dimensional systems starting from scratch and assuming very little besides basic quantum mechanics and second quantization. The formalism is developed in a self-contained fashion and applied to the spinless and spin-1/2 Luttinger models, working out both single and two particle correlation functions. The implications of these results for the specific cases of the (anisotropic) Heisenberg and the Hubbard models are discussed. Although everything in these notes can be found in the published literature, detailed and explicit calculations of most of the results are given, which may prove useful to beginning graduate students or researchers in this area. (author)
It was 20 years ago this month that particle physicists caught their first glimpse of the W boson. Now they have measured its mass so precisely that the Standard Model is facing an unprecedented challenge. (U.K.)
Spectroscopy of family gauge bosons
Spectroscopy of family gauge bosons is investigated based on a U(3) family gauge boson model proposed by Sumino. In his model, the family gauge bosons are in mass eigenstates in a diagonal basis of the charged lepton mass matrix. Therefore, the family numbers are defined by (e1,e2,e3)=(e,μ,τ), while the assignment for quark sector are free. For possible family-number assignments (q1,q2,q3), under a constraint from K0–K¯0 mixing, we investigate possibilities of new physics, e.g. production of the lightest family gauge boson at the LHC, μ−N→e−N, rare K and B decays, and so on.
Is geometry bosonic or fermionic?
Hughes, Taylor L
2011-01-01
It is generally assumed that the gravitational field is bosonic. Here we show that a simple propagating torsional theory can give rise to localized geometric structures that can consistently be quantized as fermions under exchange. To demonstrate this, we show that the model can be formally mapped onto the Skyrme model of baryons, and we use well-known results from Skyrme theory. This begs the question: {\\it Is geometry bosonic or fermionic (or both)?}
From Bosonic Strings to Fermions
Sidharth, B. G.
2006-01-01
Early string theory described Bosonic particles at the real life Compton scale. Later developments to include Fermions initiated by Ramond and others have lead through Quantum Super Strings to M-theory operating at the as yet experimentally unattainable Planck scale. We describe an alternative route from Bosonic Strings to Fermions, by directly invoking a non commutative geometry, an approach which is closer to experiment.
Analytic boosted boson discrimination
Larkoski, Andrew J.; Moult, Ian; Neill, Duff
2016-05-01
Observables which discriminate boosted topologies from massive QCD jets are of great importance for the success of the jet substructure program at the Large Hadron Collider. Such observables, while both widely and successfully used, have been studied almost exclusively with Monte Carlo simulations. In this paper we present the first all-orders factorization theorem for a two-prong discriminant based on a jet shape variable, D 2, valid for both signal and background jets. Our factorization theorem simultaneously describes the production of both collinear and soft subjets, and we introduce a novel zero-bin procedure to correctly describe the transition region between these limits. By proving an all orders factorization theorem, we enable a systematically improvable description, and allow for precision comparisons between data, Monte Carlo, and first principles QCD calculations for jet substructure observables. Using our factorization theorem, we present numerical results for the discrimination of a boosted Z boson from massive QCD background jets. We compare our results with Monte Carlo predictions which allows for a detailed understanding of the extent to which these generators accurately describe the formation of two-prong QCD jets, and informs their usage in substructure analyses. Our calculation also provides considerable insight into the discrimination power and calculability of jet substructure observables in general.
Excited Weak Bosons and Dark Matter
Fritzsch, Harald
2016-01-01
The weak bosons are bound states of new constituents, the haplons. The p-wave excitations are studied. The state with the lowest mass is identified with the boson, which has been discovered at the LHC. Specific properties of the excited bosons are discussed, in particular their decays into weak bosons and photons. Recently a two photon signal has been observed, which might come from the decay of a neutral heavy boson with a mass of about 0.75 TeV. This particle could be the excited weak tensor boson. The stable fermion, consisting of three haplons, provides the dark matter in our universe.
Zhu, S
2006-01-01
The $O$(MeV) spin-1 U-boson has been proposed to mediate the interaction among electron-positron and $O$(MeV) dark matter, in order to account for the 511 keV $\\gamma$-ray observation by SPI/INTEGRAL. In this paper the observability of such kind of U-boson at BESIII is investigated through the processes $e^+e^- \\to U \\gamma$ and $e^+e^- \\to J/\\Psi \\to e^+e^- U$. We find that BESIII and high luminosity B-factories have the comparable capacity to detect such U-boson. If U-boson decays mainly into dark matter, i.e. invisibly, BESIII can measure the coupling among U-boson and electron-positron $g_{eR}$ (see text) down to $O(10^{-5})$, and cover large parameter space which can account for 511 keV $\\gamma$-ray observation. On the other hand, provided that U decays mainly into electron-positron, BESIII can detect $g_{eR}$ down to $O(10^{-3})$, and it is hard to explore 511 keV $\\gamma$-ray measurement allowed parameter space due to the irreducible QED backgrounds.
Spin models and boson sampling
Garcia Ripoll, Juan Jose; Peropadre, Borja; Aspuru-Guzik, Alan
Aaronson & Arkhipov showed that predicting the measurement statistics of random linear optics circuits (i.e. boson sampling) is a classically hard problem for highly non-classical input states. A typical boson-sampling circuit requires N single photon emitters and M photodetectors, and it is a natural idea to rely on few-level systems for both tasks. Indeed, we show that 2M two-level emitters at the input and output ports of a general M-port interferometer interact via an XY-model with collective dissipation and a large number of dark states that could be used for quantum information storage. More important is the fact that, when we neglect dissipation, the resulting long-range XY spin-spin interaction is equivalent to boson sampling under the same conditions that make boson sampling efficient. This allows efficient implementations of boson sampling using quantum simulators & quantum computers. We acknowledge support from Spanish Mineco Project FIS2012-33022, CAM Research Network QUITEMAD+ and EU FP7 FET-Open Project PROMISCE.
A Z' Boson and the Higgs Boson Mass
Chanowitz, Michael S.
2008-01-01
The Standard Model fit prefers values of the Higgs boson mass that are below the 114 GeV direct lower limit from LEP II. The discrepancy is acute if the 3.2 sigma disagreement for the effective weak interaction mixing angle from the two most precise measurements is attributed to underestimated systematic error. In that case the data suggests new physics to raise the predicted value of the Higgs mass. One of the simplest possibilities is a Z' boson, which would generically increase the predict...
Inclusion of g boson in the microscopic sdgIBM and the g boson effect
The inclusion of g boson in the microscopic sdgIBM is presented. The collectivity of g boson, the relationship between g boson properties and the strengths of the effective nucleon-nucleon interaction, and the influence of g boson on the sdIBM are discussed in detail
Light Front Boson Model Propagation
Jorge Henrique Sales; Alfredo Takashi Suzuki
2011-01-01
stract The scope and aim of this work is to describe the two-body interaction mediated by a particle (either the scalar or the gauge boson) within the light-front formulation. To do this, first of all we point out the importance of propagators and Green functions in Quantum Mechanics. Then we project the covariant quantum propagator onto the light front time to get the propagator for scalar particles in these coordinates. This operator propagates the wave function from x+ = 0 to x+ ＞ O. It corresponds to the definition of the time ordering operation in the light front time x+. We calculate the light-front Green's function for 2 interacting bosons propagating forward in x+. We also show how to write down the light front Green's function from the Feynman propagator and finally make a generalization to N bosons.
Hartmann, Betti, E-mail: b.hartmann@jacobs-university.de [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany); Riedel, Jürgen, E-mail: j.riedel@jacobs-university.de [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany); Faculty of Physics, University Oldenburg, 26111 Oldenburg (Germany); Suciu, Raluca, E-mail: r.suciu@jacobs-university.de [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany)
2013-11-04
We construct boson stars in (4+1)-dimensional Gauss–Bonnet gravity. We study the properties of the solutions in dependence on the coupling constants and investigate in detail their properties. While the “thick wall” limit is independent of the value of the Gauss–Bonnet coupling, we find that the spiraling behaviour characteristic for boson stars in standard Einstein gravity disappears for large enough values of the Gauss–Bonnet coupling. Our results show that in this case the scalar field can not have arbitrarily high values of the scalar field at the center of the boson star and that it is hence impossible to reach the “thin wall” limit. Moreover, for large enough Gauss–Bonnet coupling we find a unique relation between the mass and the radius (qualitatively similar to those of neutron stars) which is not present in the Einstein gravity limit.
Higgs boson production at the LHC
Peters, Krisztian; The ATLAS collaboration
2015-01-01
After the discovery at the LHC, the main goal of the Higgs boson measurements at ATLAS and CMS is to fully elucidate the nature of this new particle. In this contribution we will discuss the Higgs boson production and decay properties at the LHC and the main analyses which build the fundation for the current Higgs boson property measurements. Inclusive rates as well as differential measurements in the main bosonic and fermionic channels, and searches for rarer decay modes will be presented.
An introduction to boson-sampling
Gard, Bryan T; Motes, Keith R.; Olson, Jonathan P.; Rohde, Peter P.; Dowling, Jonathan P.
2014-01-01
Boson-sampling is a simplified model for quantum computing that may hold the key to implementing the first ever post-classical quantum computer. Boson-sampling is a non-universal quantum computer that is significantly more straightforward to build than any universal quantum computer proposed so far. We begin this chapter by motivating boson-sampling and discussing the history of linear optics quantum computing. We then summarize the boson-sampling formalism, discuss what a sampling problem is...
Bosonic Coherent Motions in the Universe
Kim, Jihn E; Tsujikawa, Shinji
2014-01-01
We mini-review the role of fundamental spin-0 bosons as bosonic coherent motion (BCM) in the Universe. The fundamental spin-0 bosons have the potential to account for the baryon number generation, cold dark matter (CDM) via BCM, dark energy, and inflation. Among these, here we focus on the CDM possibility because it can be experimentally tested with the current experimental techniques. We also comment briefly on the panoply of the other roles of spin-0 bosons.
Vectorial versus axial goldstone bosons
The Yukawa interactions of fermions with Goldstone bosons are given in closed form for an arbitrary renormalizable field theory to all orders of perturbation theory or for a general effective Lagrangian. Although the diagonal couplings are always pseudoscalar there is an important difference between spontaneously broken vector and axial-vector global symmetries. Compared to the axial case, the diagonal douplings of 'vectorial' Goldstone bosons to charged fermions are suppressed by mixing angles or appear only via radiative corrections involving gauge fields. This general result may be relevant for the problem of flavour symmetry breaking in composite models. (Author)
Boson stars in the centre of galaxies?
Schunck, Franz E
2008-01-01
We investigate the possible gravitational redshift values for boson stars with a self-interaction, studying a wide range of possible masses. We find a limiting value of z_lim \\simeq 0.687 for stable boson star configurations. We can exclude the direct observation of boson stars. X-ray spectroscopy is perhaps the most interesting possibility.
A generalization of boson normal ordering
In this Letter we define generalizations of boson normal ordering. These are based on the number of contractions whose vertices are next to each other in the linear representation of the boson operator function. Our main motivation is to shed further light onto the combinatorics arising from algebraic and Fock space properties of boson operators
Introduction to the physics of Higgs bosons
Dawson, S.
1994-11-01
A basic introduction to the physics of the Standard Model Higgs boson is given. We discuss Higgs boson production in e{sup +}e{sup {minus}} and hadronic collisions and survey search techniques at future accelerators. The Higgs bosons of the minimal SUSY model are briefly considered. Indirect limits from triviality arguments, vacuum stability and precision measurements at LEP are also presented.
Charged Higgs Bosons in the LHCHXSWG
Heinemeyer, S
2014-01-01
Searches for charged Higgs bosons are an integral part of current and future investigations at the LHC. The LHC Higgs Cross Section Working Group (LHCHXSWG) was created to provide cross sections, branching ratios, analysis strategies etc. for Higgs boson searches at the LHC. We briefly review progress and results for charged Higgs bosons in and for the LHCHXSWG.
Introduction to the physics of Higgs bosons
A basic introduction to the physics of the Standard Model Higgs boson is given. We discuss Higgs boson production in e+e- and hadronic collisions and survey search techniques at future accelerators. The Higgs bosons of the minimal SUSY model are briefly considered. Indirect limits from triviality arguments, vacuum stability and precision measurements at LEP are also presented
Twisted bosonization in two dimensional noncommutative spacetime
Haque, Asrarul
2012-01-01
We study the twisted bosonization of massive Thirring model to relate to sine-Gordon model in Moyal spacetime using twisted commutation relations. We obtain the relevant twisted bosonization rules. We show that there exists dual rela- tionship between twisted bosonic and fermionic operators. The strong-weak duality is also observed to be preserved as its commutative counterpart.
Evidence of Higgs Boson Production through Vector Boson Fusion
AUTHOR|(INSPIRE)INSPIRE-00333580
The discovery of the Higgs boson in 2012 provided confirmation of the proposed mechanism for preserving the electroweak $SU(2) \\times U(1)$ gauge symmetry of the Standard Model of particle physics. It also heralded in a new era of precision Higgs physics. This thesis presents a measurement of the rate at which the Higgs boson is produced by vector boson fusion in the \\wwlnln decay channel. With gauge boson couplings in both the production and decay vertices, a VBF measurement in this channel is a powerful probe of the $VVH$ vertex strength. Using $4.5$~fb$^{-1}$ and $20.3$~fb$^{-1}$ of $pp$ collision data collected at respective center-of-mass energies of 7 and $8 \\tev$ in the ATLAS detector, measurements of the statistical significance and the signal strength are carried out in the Higgs mass range $100 \\leq m_H \\leq 200 \\gev$. These measurements are enhanced with a boosted decision tree that exploits the correlations between eight kinematic inputs in order to separate signal and background processes. At the...
Bosonic interactions with a domain wall
Morris, J R
2016-01-01
We consider here the interaction of scalar bosons with a topological domain wall. Not only is there a continuum of scattering states, but there is also an interesting "quasi-discretuum" of positive energy bosonic bound states, describing bosons entrapped within the wall's core. The full spectrum of the scattering and bound state energies and eigenstates is obtainable from a Schr\\"odinger-type of equation with a P\\"oschl-Teller potential. We also consider the presence of a boson gas within the wall and high energy boson emission.
Excited Weak Bosons and Dark Matter
Fritzsch, Harald
2016-01-01
The weak bosons are bound states of new constituents, the haplons. The p-wave excitations are studied. The state with the lowest mass is identified with the boson, which has been discovered at the LHC. Specific properties of the excited bosons are discussed, in particular their decays into weak bosons and photons. Recently a two photon signal has been observed, which might come from the decay of a neutral heavy boson with a mass of about 0.75 TeV. This particle could be the excited weak tenso...
Gravitational Stability of Boson Stars
Kusmartsev, Fjodor V; Schunck, Franz E
1991-01-01
We investigate the stability of general-relativistic boson stars by classifying singularities of differential mappings and compare it with the results of perturbation theory. Depending on the particle number, the star has the following regimes of behavior: stable, metastable, pulsation, and collapse.
The sensitivity of the Higgs boson branching ratios to the W boson width
Murray, William
2016-07-01
The Higgs boson branching ratio into vector bosons is sensitive to the decay widths of those vector bosons because they are produced with at least one boson significantly off-shell. Γ (H → VV) is approximately proportional to the product of the Higgs boson coupling and the vector boson width. ΓZ is well measured, but ΓW gives an uncertainty on Γ (H → WW) which is not negligible. The ratio of branching ratios, BR (H → WW) / BR (H → ZZ) measured by a combination of ATLAS and CMS at LHC is used herein to extract a width for the W boson of ΓW =1.8-0.3+0.4 GeV by assuming Standard Model couplings of the Higgs bosons. This dependence of the branching ratio on ΓW is not discussed in most Higgs boson coupling analyses.
The sensitivity of the Higgs boson branching ratios to the W boson width
Murray, William
2016-01-01
The Higgs boson branching ratio into vector bosons is sensitive to the decay widths of those vector bosons because they are produced with at least one boson significantly off-shell. Gamma(H to V V ) is approximately proportional to the product of the Higgs boson coupling and the vector boson width. Gamma Z is well known, but Gamma W gives an uncertainty on Gamma(H to W W ) which is not negligible. The ratio of branching ratios, BR(H to W W )/BR(H to ZZ) measured by a combination of ATLAS and CMS at LHC is used herein to extract a width for the W boson of Gamma W = 1.8+0.4-0.3 GeV by assuming Standard Model couplings of the Higgs bosons. This dependence of the branching ratio on Gamma W is not discussed in most Higgs boson coupling analyses.
Prospects for the search for Higgs bosons with vector boson fusion processes at the LHC
Rottlaender, Iris
2007-01-01
The search for the Higgs boson is one of the main physics goals of the Large Hadron Collider (LHC) and its two multi-purpose experiments, ATLAS and CMS. Vector boson fusion is the second largest production process for a standard model Higgs boson at the LHC and offers excellent means for background suppression. This paper gives an overview of the prospects of Higgs boson searches using vector boson fusion at the LHC. For a standard model Higgs boson, the decay channels H->tautau, H->WW and H-...
Introduction to bosonic string theory
This is an introductory set of five lectures on bosonic string theory. The first one deals with the classical theory of bosonic strings. The second and third lectures cover quantization. Three basic quantization methods are sketched: the old covariant formalism, the light-cone gauge quantization, where the spectrum is derived and the Polyakov path integral formalism and in particular the partition function at one loop. Finally, the last lecture covers interactions, low energy effective action, the general idea of compactification and in particular toroidal compactification. The notes are based on books by Green, Schwarz and Witten, Polchinski, Lust and Theissen and Kaku and review papers by D'Hocker and Phong and O. Alvarez. (author)
A general approach to bosonization
Girish S Setulur; V Meera
2007-10-01
We summarize recent developments in the ﬁeld of higher dimensional bosonization made by Setlur and collaborators and propose a general formula for the ﬁeld operator in terms of currents and densities in one dimension using a new ingredient known as a `singular complex number'. Using this formalism, we compute the Green function of the homogeneous electron gas in one spatial dimension with short-range interaction leading to the Luttinger liquid and also with long-range interactions that lead to a Wigner crystal whose momentum distribution computed recently exhibits essential singularities. We generalize the formalism to ﬁnite temperature by combining with the author's hydrodynamic approach. The one-particle Green function of this system with essential singularities cannot be easily computed using the traditional approach to bosonization which involves the introduction of momentum cutoffs, hence the more general approach of the present formalism is proposed as a suitable alternative.
Barbieri, Riccardo; Kannike, Kristjan; Sala, Filippo; Tesi, Andrea
2013-01-01
Now that one has been found, the search for signs of more scalars is a primary task of current and future experiments. In the motivated hypothesis that the extra Higgs bosons of the next-to-minimal supersymmetric Standard Model (NMSSM) be the lightest new particles around, we outline a possible overall strategy to search for signs of the CP-even states. This work complements Ref. arXiv:1304.3670.
The 4 of July 2012, the CERN physicists announced the discovery of the Higgs boson, a particle which existence is essential to the understanding of our world. The paper relates this day which will remain in the history of the physics of particles, and gives some details of the results of the CMS and Atlas experiments on the CERN Large Hadron Collider (LHC). Results from the Fermilab's Tevatron accelerator are also mentioned
Bosonic colored group field theory
Ben Geloun, Joseph [Universite Paris XI, Laboratoire de Physique Theorique, Orsay Cedex (France); University of Abomey-Calavi, Cotonou (BJ). International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair); Universite Cheikh Anta Diop, Departement de Mathematiques et Informatique, Faculte des Sciences et Techniques, Dakar (Senegal); Magnen, Jacques [Ecole Polytechnique, Centre de Physique Theorique, Palaiseau Cedex (France); Rivasseau, Vincent [Universite Paris XI, Laboratoire de Physique Theorique, Orsay Cedex (France)
2010-12-15
Bosonic colored group field theory is considered. Focusing first on dimension four, namely the colored Ooguri group field model, the main properties of Feynman graphs are studied. This leads to a theorem on optimal perturbative bounds of Feynman amplitudes in the ''ultraspin'' (large spin) limit. The results are generalized in any dimension. Finally, integrating out two colors we write a new representation, which could be useful for the constructive analysis of this type of models. (orig.)
Electroweak boson production at LHCb
Wallace Ronan
2013-11-01
Full Text Available Measurements of W and Z boson production provide important tests of the Standard Model as well as being inputs for determining the parton density functions of the proton. W and Z production cross-sections, and their ratios, have been measured using the LHCb detector and are reported here. Datasets of up to 1 fb−1 at √s = 7 TeV are used.
Domains of bosonic functional integrals
We propose a mathematical framework for bosonic Euclidean quantum field functional integrals based on the theory of integration on the dual algebraic vector space of classical field sources. We present a generalization of the Minlos-Dao Xing theorem and apply it to determine exactly the domain of integration associated to the functional integral representation of the two-dimensional quantum electrodynamics Schwinger generating functional. (author)
Collider Signatures of Goldstone Bosons
Cheung, Kingman; Yuan, Tzu-Chiang
2014-01-01
Recently Weinberg suggested that Goldstone bosons arising from the spontaneous breakdown of some global hidden symmetries can interact weakly in the early Universe and account for a fraction of the effective number of neutrino species N_{eff}, which has been reported persistently 2\\sigma away from its expected value of three. In this work, we study in some details a number of experimental constraints on this interesting idea based on the simplest possibility of a global U(1), as studied by Weinberg. We work out the decay branching ratios of the associated light scalar field \\sigma and suggest a possible collider signature at the Large Hadron Collider (LHC). In some corners of the parameter space, the scalar field \\sigma can decay into a pair of pions with a branching ratio of order 10% while the rest is mostly a pair of Goldstone bosons. The collider signature would be gluon fusion into the standard model Higgs boson gg -> H followed by H -> \\sigma \\sigma -> (\\pi\\pi) (\\alpha\\alpha) where \\alpha is the Goldsto...
Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider
Jai Kumar Singhal; Sardar Singh; Ashok K Nagawat
2007-06-01
We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan and A. We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson.
CMS standard model Higgs boson results
Garcia-Abia Pablo
2013-11-01
Full Text Available In July 2012 CMS announced the discovery of a new boson with properties resembling those of the long-sought Higgs boson. The analysis of the proton-proton collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 fb−1 at √s = 7 TeV and 19.6 fb−1 at √s = 8 TeV, confirm the Higgs-like nature of the new boson, with a signal strength associated with vector bosons and fermions consistent with the expectations for a standard model (SM Higgs boson, and spin-parity clearly favouring the scalar nature of the new boson. In this note I review the updated results of the CMS experiment.
An Introduction to Boson-Sampling
Gard, Bryan T.; Motes, Keith R.; Olson, Jonathan P.; Rohde, Peter P.; Dowling, Jonathan P.
2015-06-01
Boson-sampling is a simplified model for quantum computing that may hold the key to implementing the first ever post-classical quantum computer. Boson-sampling is a non-universal quantum computer that is significantly more straightforward to build than any universal quantum computer proposed so far. We begin this chapter by motivating boson-sampling and discussing the history of linear optics quantum computing. We then summarize the boson-sampling formalism, discuss what a sampling problem is, explain why boson-sampling is easier than linear optics quantum computing, and discuss the Extended Church-Turing thesis. Next, sampling with other classes of quantum optical states is analyzed. Finally, we discuss the feasibility of building a boson-sampling device using existing technology.
A semiclassical approach for the Higgs boson
Fariborz, Amir H; Schechter, Joseph
2014-01-01
Starting from the equations of motion of the fields involved in a theory with spontaneous symmetry breaking and by making simple assumptions regarding their behavior we derive simple tree level relations between the mass of the Higgs boson in the theory and the masses of the gauge bosons corresponding to the broken generators. We show that these mass relations have a clear meaning if both the scalars and the gauge bosons are composite states made of two fermions.
Probing anomalous gauge boson couplings at LEP
We bound anomalous gauge boson couplings using LEP data for the Z → bar ∫∫ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson vertices. We find that measurements at LEP constrain the three gauge boson couplings at a level comparable to that obtainable at LEPII
Fermionic subspaces of the bosonic string
Chattaraputi, Auttakit [Department of Physics, University of Chulalongkorn, Bangkok 10330 (Thailand); Englert, Francois [Service de Physique Theorique, Universite Libre de Bruxelles, Campus Plaine, CP 225, Boulevard du Triomphe, B-1050 Bruxelles (Belgium); Houart, Laurent [Service de Physique Theorique et Mathematique, Universite Libre de Bruxelles, Campus Plaine CP 231, Boulevard du Triomphe, B-1050 Brussells (Belgium); Taormina, Anne [Department of Mathematical Sciences, University of Durham, South Road, DH1 3LE Durham (United Kingdom)
2003-06-21
A universal symmetric truncation of the bosonic string Hilbert space yields all known closed fermionic string theories in ten dimensions, their D-branes and their open descendants. We highlight the crucial role played by group theory and two-dimensional conformal field theory in the construction and emphasize the predictive power of the truncation. Such circumstantial evidence points towards the existence of a mechanism which generates spacetime fermions out of bosons dynamically within the framework of bosonic string theory.
Fermionic Subspaces of the Bosonic String
Chattaraputi, A; Houart, L; Taormina, A; Chattaraputi, Auttakit; Englert, Francois; Houart, Laurent; Taormina, Anne
2003-01-01
A universal symmetric truncation of the bosonic string Hilbert space yields all known closed fermionic string theories in ten dimensions, their D-branes and their open descendants. We highlight the crucial role played by group theory and two-dimensional conformal field theory in the construction and emphasize the predictive power of the truncation. Such circumstantial evidence points towards the existence of a mechanism which generates space-time fermions out of bosons dynamically within the framework of bosonic string theory.
Fermionic Subspaces of the Bosonic String
Chattaraputi, A.; Englert, F.; Houart, L.; Taormina, A.
A universal symmetric truncation of the bosonic string Hilbert space yields all known closed fermionic string theories in ten dimensions, their D-branes and their open descendants. We highlight the crucial role played by group theory and two-dimensional conformal field theory in the construction and emphasize the predictive power of the truncation. Such circumstantial evidence points towards the existence of a mechanism which generates space-time fermions out of bosons dynamically within the framework of bosonic string theory.
Testing the Higgs Boson Coupling to Gluons
Langenegger, Urs; Strebel, Ivo
2015-01-01
We study the possibility to separate in gluon fusion loop-induced Higgs boson production from point-like production. The Higgs boson is reconstructed in the Hgg final state at very large transverse momentum. Using the Higgs boson yields (normalized to the overall rate) and the shape of the Higgs boson pt distribution the two hypotheses can be separated with 2 standard deviations with an integrated luminosity of about 500 fb^-1. The largest experimental uncertainty affecting this estimate is the background event yield. The theoretical uncertainties from missing top mass effects are large, but can be decreased with dedicated calculations.
Mele, S
2004-01-01
The high-energy and high-luminosity data-taking campaigns of the LEP e+e- collider provided the four collaborations, ALEPH, DELPHI, L3 and OPAL, with about 50 000 W-boson pairs and about a thousand singly-produced W bosons. This unique data sample has an unprecedented reach in probing some aspects of the Standard Model of the electroweak interactions, and this article reviews several achievements in the understanding of W-boson physics at LEP. The measurements of the cross sections for W-boson production are discussed, together with their implication on the existence of the coupling between Z and W bosons. The precision measurements of the magnitude of triple gauge-boson couplings are presented. The observation of the longitudinal helicity component of the W-boson spin, related to the mechanism of electroweak symmetry breaking, is described together with the techniques used to probe the CP and CPT symmetries in the W-boson system. A discussion on the intricacies of the measurement of the mass of the W boson, ...
Rotating Boson Stars and Q-Balls
Kleihaus, B; List, M; Kleihaus, Burkhard; Kunz, Jutta; List, Meike
2005-01-01
We consider axially symmetric, rotating boson stars. Their flat space limits represent spinning Q-balls. We discuss their properties and determine their domain of existence. Q-balls and boson stars are stationary solutions and exist only in a limited frequency range. The coupling to gravity gives rise to a spiral-like frequency dependence of the boson stars. We address the flat space limit and the limit of strong gravitational coupling. For comparison we also determine the properties of spherically symmetric Q-balls and boson stars.
Landau-Yang theorem and decays of a Z' boson into two Z bosons.
Keung, Wai-Yee; Low, Ian; Shu, Jing
2008-08-29
We study the decay of a Z' boson into two Z bosons by extending the Landau-Yang theorem to a parent particle decaying into two Z bosons. For a spin-1 parent the theorem predicts that (1) there are only two possible couplings and (2) the normalized differential cross section depends on kinematics only through a phase shift in the azimuthal angle between the two decay planes of the Z boson. When the parent is a Z' the two possible couplings are anomaly induced and CP violating, respectively. At the CERN Large Hadron Collider their effects could be disentangled when both Z bosons decay leptonically. PMID:18851602
On Nonlinear Bosonic Coherent States
Genovese, Marco; Rasetti, Mario
2009-01-01
Nonlinear coherent states are an interesting resource for quantum technologies. Here we investigate some critical features of the single-boson nonlinear coherent states, which are theoretically constructed as eigenstates of the annihilation operator and experimentally realized as stationary states of a trapped laser-driven ion. We show that the coherence and the minimum-uncertainty properties of such states are broken for values of the Lamb-Dicke parameter corresponding to the roots of the Laguerre polynomials, which enter their explicit expression. The case of the multiboson nonlinear coherent states is also discussed.
Buchmüller, O L; Thompson, J C
2002-01-01
the status of the measurement of the W boson mass at LEP-2 is reviewed. Properties of the W such as branching ration into quarks and leptons and couplings to other neutral gauge bosons are reported. 4-fermion production cross-sections in e sup + e sup - collisions are also presented. (authors)
Analysis of boson cascade laser characteristics
Ivanov, K. A.; Kaliteevskaya, N. A.; Gubaidullin, A. R.; Kaliteevski, M. A.
2015-11-01
The dependence of the level population on pumping in a boson cascade laser has been theoretically studied. Analytical expressions for the population of various cascade levels and the terahertz mode below and above the pumping threshold are obtained. Formulas for the pumping threshold and external quantum efficiency of the boson cascade laser are derived.
Jalilian-Marian, Jamal
1994-01-01
We study radiative decay modes of the Z-boson into heavy quark bound states. We find that the widths for these decays are extremely small. We conclude that these decays will not be detectable for the time being unless there is a significant increase in the number of Z-bosons produced at the electron- positron colliders.
Diffractive Higgs Boson photoproduction in peripheral collisions
An alternative process is proposed for the diffractive Higgs boson production inspired in the Durham model, exploring it through the photon-proton interaction. In this sense, we estimate the production cross section of the Higgs boson, comparing some sets of parton distributions in the proton and confronting this results with those from other processes. (author)
Goldstone Bosons as Fractional Cosmic Neutrinos
Weinberg, Steven
2013-01-01
It is suggested that Goldstone bosons may be masquerading as fractional cosmic neutrinos, contributing about 0.39 to what is reported as the effective number of neutrino types in the era before recombination. The broken symmetry associated with these Goldstone bosons is further speculated to be the conservation of the particles of dark matter.
Electroweak gauge boson polarisation at the LHC
Stirling, W J
2012-01-01
We study the polarisation of gauge bosons produced at the LHC. Polarisation effects for W bosons manifest themselves in the angular distributions of the lepton and in the distributions of lepton transverse momentum and missing transverse energy. The distributions also depend on the selection cuts, with kinematic effects competing with polarisation effects. The polarisation is discussed for a range of different processes producing W bosons: W+jets, W from top (single and pair) production, W pair production and W production in association with a Z or Higgs boson. The relative contributions of the different polarisation states varies from process to process, reflecting the dynamics of the underlying hard-scattering process. We also present results for the polarisation of the Z boson produced in association with QCD jets at the LHC, and comment on the differences between W and Z production.
The Boson peak in supercooled water.
Kumar, Pradeep; Wikfeldt, K Thor; Schlesinger, Daniel; Pettersson, Lars G M; Stanley, H Eugene
2013-01-01
We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line TW. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih. PMID:23771033
Search for new heavy charged gauge bosons
Magass, Carsten Martin [RWTH Aachen Univ. (Germany)
2007-11-02
Additional gauge bosons are introduced in many theoretical extensions to the Standard Model. A search for a new heavy charged gauge boson W' decaying into an electron and a neutrino is presented. The data used in this analysis was taken with the D0 detector at the Fermilab proton-antiproton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of about 1 fb^{-1}. Since no significant excess is observed in the data, an upper limit is set on the production cross section times branching fraction σ_{W'}xBr (W' → ev). Using this limit, a W' boson with mass below ~1 TeV can be excluded at the 95% confidence level assuming that the new boson has the same couplings to fermions as the Standard Model W boson.
Search for new heavy charged gauge bosons
Magass, Carsten Martin; /RWTH Aachen U.
2007-11-01
Additional gauge bosons are introduced in many theoretical extensions to the Standard Model. A search for a new heavy charged gauge boson W{prime} decaying into an electron and a neutrino is presented. The data used in this analysis was taken with the D0 detector at the Fermilab proton-antiproton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of about 1 fb{sup -1}. Since no significant excess is observed in the data, an upper limit is set on the production cross section times branching fraction {sigma}{sub W{prime}}xBr (W{prime} {yields} e{nu}). Using this limit, a W{prime} boson with mass below {approx}1 TeV can be excluded at the 95% confidence level assuming that the new boson has the same couplings to fermions as the Standard Model W boson.
Orbital dynamics of binary boson star systems
We extend our previous studies of head-on collisions of boson stars by considering orbiting binary boson stars. We concentrate on equal-mass binaries and study the dynamical behavior of boson/boson and boson/antiboson pairs. We examine the gravitational wave output of these binaries and compare with other compact binaries. Such a comparison lets us probe the apparent simplicity observed in gravitational waves produced by black hole binary systems. In our system of interest however, there is an additional internal freedom which plays a significant role in the system's dynamics, namely, the phase of each star. Our evolutions show rather simple behavior at early times, but large differences occur at late times for the various initial configurations
Various Models Mimicking the SM Higgs Boson
Chang, Jung; Tseng, Po-Yan; Yuan, Tzu-Chiang; 10.1142/S0217751X1230030X
2012-01-01
This review is based on the talk presented at the SUSY 2012 (Beijing). The new particle around 125 GeV observed at the Large Hadron Collider (LHC) is almost consistent with the standard model Higgs boson, except that the diphoton decay mode may be excessive. We summarize a number of possibilities. While at the LHC the dominant production mechanism for the Higgs boson of the standard model and some other extensions is via the gluon fusion process, the alternative vector-boson fusion is more sensitive to electroweak symmetry breaking. Using the well known dijet-tagging technique to single out the vector-boson fusion mechanism, we investigate potential of vector-boson fusion to discriminate a number of models suggested to give an enhanced inclusive diphoton production rate.
Boson Sampling for Molecular Vibronic Spectra
Huh, Joonsuk; Peropadre, Borja; McClean, Jarrod R; Aspuru-Guzik, Alán
2014-01-01
Quantum computers are expected to be more efficient in performing certain computations than any classical machine. Unfortunately, the technological challenges associated with building a full-scale quantum computer have not yet allowed the experimental verification of such an expectation. Recently, boson sampling has emerged as a problem that is suspected to be intractable on any classical computer, but efficiently implementable with a linear quantum optical setup. Therefore, boson sampling may offer an experimentally realizable challenge to the Extended Church-Turing thesis and this remarkable possibility motivated much of the interest around boson sampling, at least in relation to complexity-theoretic questions. In this work, we show that the successful development of a boson sampling apparatus would not only answer such inquiries, but also yield a practical tool for difficult molecular computations. Specifically, we show that a boson sampling device with a modified input state can be used to generate molecu...
A Higgs boson is a particle whose existence is predicted in a class of quantum field theories in which a symmetry under a Lie group of transformations of the fields is spontaneously broken by an asymmetric vacuum state. It is a quantum of certain excitations of the order parameter. Such spontaneous symmetry breaking was first proposed as a feature of theories of elementary particles in 1960, but it has a much longer history in the contest of condensed matter theory: in ferromagnetism as early as 1928, in superfluidity and also in superconductivity. It was Nambu who in 1960 first proposed relativistic models inspired by BCS theory as a means of generating fermion masses in elementary particle physics but the hadronic models he proposed lacked the local gauge invariance of their prototype. The connection between spontaneous symmetry and Goldstone bosons in relativistic theories were formally proved in 1962 but the experimental evidence against the existence of such particles in the real world cast a doubt on the viability of Nambu's ideas. Between 1962 and 1964 a debate developed in the literature about whether the Goldstone theorem could be evaded. The resolution of this difficulty finally came in 1964, when Higgs realized that theories with a local gauge invariance fail to satisfy one of the axioms on which the 1962 proof of the Goldstone theorem depends. By the end of July 1964, Higgs had also written down the simplest field-theoretic model that is now known as the Higgs model. (A.C.)
Csorgo, T
2013-01-01
One of the highlights of 2012 in physics is related to two papers, published by the ATLAS and the CMS Collaborations, that announced the discovery of at least one new particle in pp collisions at CERN LHC. At least one of the properties of this new particle is found to be similar to that of the Higgs boson, the last and most difficult to find building block from the Standard Model of particle physics. Physics teachers are frequently approached by their media-educated students, who inquire about the properties of the Higgs boson, but physics teachers are rarely trained to teach this elusive aspect of particle physics in elementary, middle or junior high schools. In this paper I describe a card-game, that can be considered as a hands-on and easily accessible tool that allows interested teachers, students and also motivated lay-persons to play with the properties of the newly found Higgs-like particle. This new particle was detected through its decays to directly observable, final state particles. Many of these ...
Stephanie McClellan
2013-01-01
Before embarking on a successful career as a musician, Alan Parsons started out as a sound engineer - earning his first credit on The Beatles’ Abbey Road. Over the years, he has worked and collaborated with various artists, but 30 September 2013 marks a unique collaboration. For CERN’s ‘Bosons & More’ party, Alan Parsons Live Project will be sharing the stage with the Orchestre de la Suisse Romande. Having already visited CERN in 2011, Alan Parsons provides an insight into his views on science and his upcoming performance at the ‘Bosons & More’ event. Alan Parsons during his visit to CERN in August 2011. Since visiting CERN in 2011, how have your feelings towards the Organization developed? I was thrilled to hear about the recent discovery and how years of work had paid off. Together with my wife, Lisa, and my band, we were very privileged to come to CERN a couple of years ago, hav...
Higgs boson research in e+e- collisions
This lesson is about the experimental results obtained in 1990, at LEP concerning Higgs boson research. The main topics studied are: Higgs boson research of minimal Standard Model, then beyond the minimal model, the charged Higgs boson research in 2-doublets model, and finally, neutral Higgs boson research in a specific 2-doublets model, the minimal supersymmetric standard model
Christensen, Neil; Su, Shufang
2012-01-01
The recent results on Higgs boson searches from LHC experiments provide significant guidance in exploring the Minimal Supersymmetric (SUSY) Standard Model (MSSM) Higgs sector. If we accept the existence of a SM-like Higgs boson in the mass window of 123 GeV-127 GeV as indicated by the observed gamma,gamma events, there are two distinct mass regions (in mA) left in the MSSM Higgs sector: (a) the lighter CP-even Higgs boson being SM-like and the non-SM-like Higgs bosons all heavy and nearly degenerate above 300 GeV (an extended decoupling region); (b) the heavier CP-even Higgs boson being SM-like and the neutral non-SM-like Higgs bosons all nearly degenerate around 100 GeV (a small non-decoupling region). On the other hand, due to the strong correlation between the Higgs decays to W+W- and to gamma,gamma predicted in the MSSM, the apparent absence of a W+W- final state signal is in direct conflict with the gamma,gamma peak. If the deficit in the W+W- channel persists, it would imply that the SM-like Higgs boson...
Composite Weak Bosons at the Large Hadronic Collider
Fritzsch, Harald
2016-01-01
In a composite model of the weak bosons the p-wave bosons are studied. The state with the lowest mass is identified with the boson, which has been discovered at the LHC. Specific properties of the excited bosons are discussed, in particular their decays into weak bosons and photons. Recently a two photon signal has been observed, which might come from the decay of a neutral heavy boson with a mass of about 0.75 TeV. This particle could be an excited weak tensor boson.
Search for a Higgs Boson Decaying to Weak Boson Pairs at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hakobyan, R S; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Nowak, H; Ofierzynski, R A; Organtini, G; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofiev, D O; Prokofev, D; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Roux, B; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Sanders, M P; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2003-01-01
A Higgs particle produced in association with a Z boson and decaying into weak boson pairs is searched for in 336.4 1/pb of data collected by the L3 experiment at LEP at centre-of-mass energies from 200 to 209 GeV. Limits on the branching fraction of the Higgs boson decay into two weak bosons as a function of the Higgs mass are derived. These results are combined with the L3 search for a Higgs boson decaying to photon pairs. A Higgs produced with a Standard Model e+e- --> Zh cross section and decaying only into electroweak boson pairs is excluded at 95% CL for a mass below 107 GeV.
Bosonic string theory with dust
We study a modified bosonic string theory that has a pressureless ‘dust’ field on the string worldsheet. The dust is a real scalar field with unit gradient which breaks conformal invariance. Hamiltonian analysis reveals a time reparametrization constraint linear in the dust field momentum and a spatial diffeomorphism constraint. This feature provides a natural ‘dust time’ gauge in analogy with the parametrized particle. In this gauge we give a Fock quantization of the theory, which is complete and self-consistent in d < 26. The Hamiltonian of the theory is not a constraint; as a consequence the Hilbert space and mass spectrum are characterized by an additional parameter, and includes the usual string spectrum as a special case. The other sectors provide new particle spectra, some of which do not have tachyons. (paper)
Leptogenesis and neutral gauge bosons
Heeck, Julian
2016-01-01
We consider low-scale leptogenesis via right-handed neutrinos $N$ coupled to a $Z'$ boson, with gauged $U(1)_{B-L}$ as a simple realization. Keeping the neutrinos sufficiently out of equilibrium puts strong bounds on the $Z'$ coupling strength and mass, our focus being on light $Z'$ and $N$, testable in the near future by SHiP, HPS, Belle II, and at the LHC. We show that leptogenesis could be robustly falsified in a large region of parameter space by the double observation of $Z'$ and $N$, e.g. in the channel $pp\\to Z' \\to NN$ with displaced $N$-decay vertex, and by several experiments searching for light $Z'$, according to the mass of $N$.
Bentivegna, Marco; Spagnolo, Nicolò; Sciarrino, Fabio
2016-04-01
Is it possible to assess the correct functioning of a quantum device which eludes efficient computation of the expected results? The BosonSampling protocol is one of the best candidates to experimentally demonstrate the superior computational power of quantum mechanics, but the problem of its results certification requires the development of new methodologies, when the size of the problem becomes too large for a complete classical simulation. A recent work (Walschaers et al 2016 New J. Phys. 18 032001) has provided a significant step forward in this direction, by developing a statistical test to identify particle types in a many-body interference pattern. This tool can be applied in a general scenario to assess and investigate multi-particle coherent dynamics.
Vector Boson Scattering at ATLAS
Ozcan, V E
2009-01-01
While the Higgs model is the best studied scenario of electroweak symmetry breaking, there is no fundamental reason for the physics responsible for the symmetry breaking to be weakly-coupled. Many alternatives exist, predicting highly model-dependent signatures. By measuring the cross-section for the W and Z scattering at the LHC, it will be possible to obtain model-independent evidence for strong symmetry breaking or to constrain these various models. ATLAS Collaboration has recently performed a realistic simulation of this process and its backgrounds, which takes into account the detector effects and has developed new jet-analysis techniques for identifying vector bosons within the immense QCD backgrounds expected at the LHC. These techniques and the prospects for measuring the scattering signal will be presented.
Weak gauge boson radiation in parton showers
The emission of W and Z gauge bosons off quarks is included in a traditional QCD + QED shower. The unitarity of the shower algorithm links the real radiation of the weak gauge bosons to the negative weak virtual corrections. The shower evolution process leads to a competition between QCD, QED and weak radiation, and allows for W and Z boson production inside jets. Various effects on LHC physics are studied, both at low and high transverse momenta, and effects at higher-energy hadron colliders are outlined
Masses of Higgs bosons in supersymmetric theories
A simple method for Higgs boson mass calculation in the MSSM and in its minimal extension, the so-called next-to-minimal supersymmetric standard model (NMSSM), is suggested. The approach is based on the hierarchic structure of the mass matrix. Such matrices are obtained within the framework of MSSM and NMSSM. The simple analytical expression for Higgs boson spectrum in both these models are obtained. It was shown that the mass of the lightest Higgs boson in the NMSSM can be essentially lighter than its upper bound
Improved effective vector boson approximation revisited
Bernreuther, Werner
2015-01-01
We reexamine the improved effective vector boson approximation which is based on two-vector-boson luminosities $\\mathrm{\\mathbf{L}}_{\\rm pol}$ for the computation of weak gauge-boson hard scattering subprocesses $V_1 V_2\\to {\\cal W}$ in high-energy hadron-hadron or $e^-e^+$ collisions. We calculate these luminosities for the nine combinations of the transverse and longitudinal polarizations of $V_1$ and $V_2$. The quality of this approach is investigated for the reactions $e^-e^+ \\to W^- W^+ \
Bosonic thermoelectric transport and breakdown of universality
We discuss the general principles of transport in normal phase atomic gases, comparing Bose and Fermi systems. Our study shows that two-dimensional bosonic transport is non-universal with respect to different dissipation mechanisms. Near the superfluid transition temperature Tc, a striking similarity between the fermionic and bosonic transport emerges because super-conducting (fluid) fluctuation transport for Fermi gases is dominated by the bosonic, Cooper pair component. As in fluctuation theory, one finds that the Seebeck coefficient changes sign at Tc and the Lorenz number approaches zero at Tc. Our findings appear quantitatively consistent with recent Bose gas experiments. (paper)
An enigma called the Higgs boson
The search for the Higgs boson, the missing pillar of the currently prevailing theory of weak and electromagnetic interactions, is a prime goal of the Large Hadron Collider (LHC) experiment. We review the circumstances, based on which our expectation of the existence of the Higgs boson has grown, how it is expected to be seen at the LHC, and where we stand in the drop of the presently available data. Moreover, we touch upon the fact that the very existence of the Higgs boson as an elementary particle provides a strong hint on possible new laws of physics. (author)
Mapping the genuine bosonic quartic couplings
Eboli, O J P
2016-01-01
The larger center-of-mass energy of the Large Hadron Collider Run 2 opens up the possibility of a more detailed study of the quartic vertices of the electroweak gauge bosons. Our goal in this work is to classify all operators possessing quartic interactions among the electroweak gauge bosons that do not exhibit triple gauge-boson vertices associated to them. We obtain all relevant operators in the non-linear and linear realizations of the $SU(2)_L \\otimes U(1)_Y$ gauge symmetry.
A light Higgs Boson would invite Supersymmmetry
Ellis, Jonathan Richard; Ellis, John; Ross, Douglas
2001-01-01
If the Higgs boson weighs about 115 GeV, the effective potential of the Standard Model becomes unstable above a scale of about 10^6 GeV. This instability may be rectified only by new bosonic particles such as stop squarks. However, avoiding the instability requires fine-tuning of the model couplings, in particular if the theory is not to become non-perturbative before the Planck scale. Such fine-tuning is automatic in a supersymmetric model, but is lost if there are no Higgsinos. A light Higgs boson would be prima facie evidence for supersymmetry in the top-quark and Higgs sectors.
The Goldstone boson equivalence theorem with fermions
Durand, Loyal; Riesselmann, Kurt
1995-01-01
The calculation of the leading electroweak corrections to physical transition matrix elements in powers of $M_H^2/v^2$ can be greatly simplified in the limit $M_H^2\\gg M_W^2,\\, M_Z^2$ through the use of the Goldstone boson equivalence theorem. This theorem allows the vector bosons $W^\\pm$ and $Z$ to be replaced by the associated scalar Goldstone bosons $w^\\pm$, $z$ which appear in the symmetry breaking sector of the Standard Model in the limit of vanishing gauge couplings. In the present pape...
Searches for heavy Higgs bosons decaying to light Higgs bosons with a mass of 125 GeV
Lane, Rebecca
2015-01-01
Searches for Higgs bosons decaying to a pair of Higgs bosons (hh or hA) or for a Higgs boson decaying to Zh/ZA are presented. Different analyses involving Higgs boson decays into bottom-quarks, tau pairs, and diphotons will be summarized in this talk.
Search for nonminimal neutral Higgs bosons from Z-boson decays
Using the Mark II detector at the SLAC Linear Collider, we search for decays of the Z boson to a pair of nonminimal Higgs bosons (Z→Hs0Hp0), where one of them is relatively light (approx-lt 10 GeV). We find no evidence for these decays and we obtain limits on the ZHs0Hp0 coupling as a function of the Higgs-boson masses
Research on Higgs bosons by positron-electron collisions
The experimental results obtained at LEP concerning Higgs bosons research are discussed. The existence of the Higgs bosons, from the Standard Model principles, is reviewed. The investigations on charged and neutral Higgs bosons are discussed taking into account a two-doublets model. The investigations show: that the Higgs bosons cannot be found between zero and 41 GeV, and that the Higgs boson mass is approximately 40 GeV
Weak boson production via vector-boson fusion rate at NLO matched with Powheg
The production of weak vector-bosons in association with two jets is an important background to Higgs-boson searches in vector-Boson fusion (VBF) at the LHC. In order to make reliable predictions, the combination of fixed-order NLO-calculations and parton-showers is indispensable. We present the implementation of the weak boson production via VBF in the Powheg-Box. This is a first step to interface Vbfnlo, a fully flexible Monte Carlo program, with the Powheg-Box.
Landau-Yang Theorem and Decays of a Z' Boson into Two Z Bosons
Keung, Wai-Yee; Low, Ian; Shu, Jing
2008-01-01
We study the decay of a Z' boson into two Z bosons by extending the Landau-Yang theorem to a parent particle decaying into two Z bosons. For a spin-1 parent the theorem predicts: 1) there are only two possible couplings and 2) the normalized differential cross-section depends on kinematics only through a phase shift in the azimuthal angle between the two decay planes of the Z boson. When the parent is a Z' the two possible couplings are anomaly-induced and CP-violating, respectively. At the L...
Experimentalists and theorists are still celebrating the Nobel-worthy discovery of the Higgs boson that was announced in July 2012 at CERN’s Large Hadron Collider. Now they are working on the profound implications of that discovery
Bosonic superconformal Toda model and dressing transformation
The authors show the dressing transformations of the basic field and the classical chiral operators in the Bosonic Superconformal Toda model. After quantization, The related quantum algebra is obtained
Acquiring a taste for the Higgs boson
Caroline Duc
2012-01-01
Before CERN's scientists had even announced the discovery of the Higgs boson, others were already attributing some interesting characteristics to it: flavoursome, sparkling and liquid... The artisan brewery Hopfenstark in Quebec launched its new "Higgs boson" beer in November 2010. Ever since, it has been intriguing enthusiasts with its unique taste explosion. The boson was a source of inspiration for brewer Frédéric Cormier, the Hopfenstark brewery's owner, who is a big fan of science programmes. "I returned from a trip to Europe in 2010 with the idea for a new beer that would be unlike any other," he explains. "I was always reading and hearing about CERN's particle accelerator in the media, so I did some research on the famous Higgs boson and decided to give my new creation the same name." For Frédéric Cormier, it's important that the names of his beers refle...
A Historical Profile of the Higgs Boson
Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.
2012-01-31
The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Quantum geometry of bosonic strings - revisited
We review the original paper by A.M. Polyakov (Quantum Geometry of Bosonic Strings) with corrections and improvements the concepts exposed there and following as closely as possible to the original A.M. Polyakov's paper. (author)
Boson representation of the asymmetric rotator
The yrast states, as well as the wobbling frequency are analyzed using alternatively the Holstein-Primakoff and Dyson boson expansions. Both the prolate and oblate shapes are treated using Oz as quantization axis. (author)
Microscopic boson approach to nuclear collective motion
A quantum mechanical approach to the maximally decoupled nuclear collective motion is proposed. The essential idea is to transcribe the original shell-model Hamiltonian in terms of boson operators, then to isolate the collective one-boson eigenstates of the mapped Hamiltonian and to perform a canonical transformation which eliminates (up to the two-body terms) the coupling between the collective and noncollective bosons. Unphysical states arising due to the violtion of the Pauli principle in the boson space are identified and removed within a suitable approximation. The method is applied to study the low-lying collective states of nuclei which are successfully described by the exactly solvable multilevel pairing Hamiltonian (Sn, Ni, Pb). 75 refs.; 8 figs
The pomeron in closed bosonic string theory
Fazio, A R
2010-01-01
We review the features of the pomeron in the S-matrix theory and in quantum field theory. We extend those general properties to the pomeron of closed bosonic string theory in a Minkowskian background. We compute the couplings of the pomeron to the lowest mass levels of closed bosonic string states in flat space. We recognize the deviation from the linearity of the Regge trajectories in a five dimensional anti De Sitter background.
Fermion boson metamorphosis in field theory
In two-dimensional field theories many features are especially transparent if the Fermi fields are represented by non-local expressions of the Bose fields. Such a procedure is known as boson representation. Bilinear quantities appear in the Lagrangian of a fermion theory transform, however, as simple local expressions of the bosons so that the resulting theory may be written as a theory of bosons. Conversely, a theory of bosons may be transformed into an equivalent theory of fermions. Together they provide a basis for generating many interesting equivalences between theories of different types. In the present work a consistent scheme for constructing a canonical Fermi field in terms of a real scalar field is developed and such a procedure is valid and consistent with the tenets of quantum field theory is verified. A boson formulation offers a unifying theme in understanding the structure of many theories. This is illustrated by the boson formulation of a multifermion theory with chiral and internal symmetries. The nature of dynamical generation of mass when the theory undergoes boson transmutation and the preservation of continuous chiral symmetry in the massive case are examined. The dynamics of the system depends to a great extent on the specific number of fermions and different models of the same system can have very different properties. Many unusual symmetries of the fermion theory, such as hidden symmetry, duality and triality symmetries, are only manifest in the boson formulation. The underlying connections between some models with U(N) internal symmetry and another class of fermion models built with Majorana fermions which have O(2N) internal symmetry are uncovered
Vector-boson-induced neutrino mass
One-loop radiative Majorana neutrino masses through the exchange of scalars have been considered for many years. We show for the first time how such a one-loop mass is also possible through the exchange of vector gauge bosons. It is based on a simple variation of a recently proposed SU(2)N extension of the Standard Model, where a vector boson is a candidate for the dark matter of the Universe.
Study of single W bosons at JLC
Arogancia, Dennis C.; Sanchez, Allister Levi C.; Magallanes, Jingle B.; Gooc, Hermogenes C.; Bacala, Angelina M. [Mindanao State Univ., Dept. of Physics, Iligan (Philippines); Fujii, Keisuke; Miyamoto, Akiya [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)
2001-06-01
Single W bosons are studied through computer simulation using the process e{sup +}e{sup -} {yields} e{sup +}{nu}{sub e}W{sup -} where it decays into two hadronic jets. This study focuses of the measurement of W boson mass with and without beamstrahlung and initial state radiation (ISR) effects. The JLC Study Framework (JSF) is employed for this purpose. The center-of-mass energy is set at 500 GeV. (author)
Higgs bosons in the simplest SUSY models
Nevzorov, R. B.; Ter-Martirosyan, K. A.; Trusov, M.A.
2001-01-01
Nowadays in the MSSM the moderate values of $\\tan\\beta$ are almost excluded by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal Supersymmetric Standard Model the theoretical upper bound on it increases and reaches maximal value in the strong Yukawa coupling limit when all solutions of renormalization group equations are concentrated near the quasi-fixed point. For calculation of Higgs boson spectrum the perturbation theory method can be applied. We investigate the p...
Unconventional quantum phases of lattice bosonic mixtures
Buonsante, P.; Giampaolo, S. M.; Illuminati, F.; Penna, V; Vezzani, A.
2008-01-01
We consider strongly interacting boson-boson mixtures on one-dimensional lattices and, by adopting a qualitative mean-field approach, investigate their quantum phases as the interspecies repulsion is increased. In particular, we analyze the low-energy "quantum emulsion" metastable states occurring at large values of the interspecies interaction, which are expected to prevent the system from reaching its true ground state. We argue a significant decrease in the visibility of the time-of-flight...
Deformed Bosons: Combinatorics of Normal Ordering
Blasiak, P; Penson, K A; Solomon, A I
2004-01-01
We solve the normal ordering problem for (A* A)^n where A* (resp. A) are one mode deformed bosonic creation (resp. annihilation) operators satisfying [A,A*]=[N+1]-[N]. The solution generalizes results known for canonical and q-bosons. It involves combinatorial polynomials in the number operator N for which the generating functions and explicit expressions are found. Simple deformations provide examples of the method.
Electroweak Precision Data and New Gauge Bosons
Erler, Jens
2009-01-01
I review constraints on the Standard Model (SM) Higgs boson from high energy electroweak (EW) precision data. The same data set also strongly limits various mixing effects of hypothetical extra neutral gauge bosons (Z') with the ordinary Z. I also discuss low energy precision measurements which are sensitive to other aspects of Z' physics, such as the direct exchange amplitude and the flavor or CP violating sectors.
Precision Probes of a Leptophobic Z' Boson
Buckley, Matthew R.; Ramsey-Musolf, Michael J.
2012-01-01
Extensions of the Standard Model that contain leptophobic Z' gauge bosons are theoretically interesting but difficult to probe directly in high-energy hadron colliders. However, precision measurements of Standard Model neutral current processes can provide powerful indirect tests. We demonstrate that parity-violating deep inelastic scattering of polarized electrons off of deuterium offer a unique probe leptophobic Z' bosons with axial quark couplings and masses above 100 GeV. In addition to c...
Microscopic foundation of the interacting boson model
A microscopic foundation of the interacting boson model is described. The importance of monopole and quadrupole pairs of nucleons is emphasized. Those pairs are mapped onto the s and d bosons. It is shown that this mapping provides a good approximation in vibrational and transitional nuclei. In appendix, it is shown that the monopole pair of electrons plays possibly an important role in metal clusters. (orig.)
Vector bosons in the expanding universe
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 m2→0 limit of these solutions. (orig.)
SU(N) Irreducible Schwinger Bosons
Mathur, Manu; Raychowdhury, Indrakshi; Anishetty, Ramesh
2010-01-01
We construct SU(N) irreducible Schwinger bosons satisfying certain U(N-1) constraints which implement the symmetries of SU(N) Young tableaues. As a result all SU(N) irreducible representations are simple monomials of $(N-1)$ types of SU(N) irreducible Schwinger bosons. Further, we show that these representations are free of multiplicity problems. Thus all SU(N) representations are made as simple as SU(2).
Supersymmetry search via gauge boson fusion
Anindya Datta
2003-02-01
We propose a novel method for the search of supersymmetry, especially for the electroweak gauginos at the large hadron collider (LHC). Gauge boson fusion technique was shown to be useful for heavy and intermediate mass Higgs bosons. In this article, we have shown that this method can also be applied to ﬁnd the signals of EW gauginos in supersymmetric theories where the canonical search strategies for these particles fail.
Neutral Supersymmetric Higgs Boson Searches
Robinson, Stephen Luke; /Imperial Coll., London
2009-09-01
In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-tagging and in the application of these techniques to the MSSM Higgs search. Work was carried out on the Level-3 trigger b-tagging algorithms. The impact parameter (IP) b-tagger was retuned and the effects of increased instantaneous luminosity on the tagger were studied. An extension of the IP-tagger to use the z-tracking information was developed. A new b-tagger using secondary vertices was developed and commissioned. A tool was developed to allow the use of large multi-run samples for trigger studies involving b-quarks. Offline, a neural network (NN) b-tagger was trained combining the existing offline lifetime based b-tagging tools. The efficiency and fake rate of the NN b-tagger were measured in data and MC. This b-tagger was internally reviewed and certified by the Collaboration and now provides the official b-tagging for all analyses using the Run IIa dataset at D0. A search was performed for neutral MSSM Higgs bosons decaying to a b{bar b} pair and produced in association with one or more b-quarks. Limits are set on the cross-section times the branching ratio for such a process. The limits were interpreted in various MSSM scenarios. This analysis uses the NN b-tagger and was the first to use this tool. The analysis also relies on triggers using the Level-3 IP b-tagging tool described previously. A likelihood discriminant was used to improve the analysis and a neural network was developed to cross-check this technique. The result of the analysis has been submitted to PRL
Neutral Supersymmetric Higgs Boson Searches
Robinson, Stephen Luke [Imperial College, London (United Kingdom)
2008-07-01
In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-tagging and in the application of these techniques to the MSSM Higgs search. Work was carried out on the Level-3 trigger b-tagging algorithms. The impact parameter (IP) b-tagger was retuned and the effects of increased instantaneous luminosity on the tagger were studied. An extension of the IP-tagger to use the z-tracking information was developed. A new b-tagger using secondary vertices was developed and commissioned. A tool was developed to allow the use of large multi-run samples for trigger studies involving b-quarks. Offline, a neural network (NN) b-tagger was trained combining the existing offline lifetime based b-tagging tools. The efficiency and fake rate of the NN b-tagger were measured in data and MC. This b-tagger was internally reviewed and certified by the Collaboration and now provides the official b-tagging for all analyses using the Run IIa dataset at D0. A search was performed for neutral MSSM Higgs bosons decaying to a b{bar b} pair and produced in association with one or more b-quarks. Limits are set on the cross-section times the branching ratio for such a process. The limits were interpreted in various MSSM scenarios. This analysis uses the NN b-tagger and was the first to use this tool. The analysis also relies on triggers using the Level-3 IP b-tagging tool described previously. A likelihood discriminant was used to improve the analysis and a neural network was developed to cross-check this technique. The result of the analysis has been submitted to PRL
Search for the Standard Model Higgs Boson in associated production with w boson at the Tevatron
Chun, Xu; /Michigan U.
2009-11-01
A search for the Standard Model Higgs boson in proton-antiproton collisions with center-of-mass energy 1.96 TeV at the Tevatron is presented in this dissertation. The process of interest is the associated production of W boson and Higgs boson, with the W boson decaying leptonically and the Higgs boson decaying into a pair of bottom quarks. The dataset in the analysis is accumulated by the D0 detector from April 2002 to April 2008 and corresponding to an integrated luminosity of 2.7 fb{sup -1}. The events are reconstructed and selected following the criteria of an isolated lepton, missing transverse energy and two jets. The D0 Neural Network b-jet identification algorithm is further used to discriminate b jets from light jets. A multivariate analysis combining Matrix Element and Neural Network methods is explored to improve the Higgs boson signal significance. No evidence of the Higgs boson is observed in this analysis. In consequence, an observed (expected) limit on the ratio of {sigma} (p{bar p} {yields} WH) x Br (H {yields} b{bar b}) to the Standard Model prediction is set to be 6.7 (6.4) at 95% C.L. for the Higgs boson with a mass of 115 GeV.
(Super)rare decays of an extra Z' boson via Higgs boson emission
Kozlov, G. A.
1999-01-01
The phenomenological model of an extra U(1) neutral gauge Z' boson coupled to heavy quarks is presented. In particular, we discuss the probability for a light $Z_{2}$ mass eigenstate decay into a bound state composed of heavy quarks via Higgs boson emission.
Search for the Standard Model Higgs Boson in associated production with w boson at the Tevatron
Chun, Xu [Univ. of Michigan, Ann Arbor, MI (United States)
2009-11-01
A search for the Standard Model Higgs boson in proton-antiproton collisions with center-of-mass energy 1.96 TeV at the Tevatron is presented in this dissertation. The process of interest is the associated production of W boson and Higgs boson, with the W boson decaying leptonically and the Higgs boson decaying into a pair of bottom quarks. The dataset in the analysis is accumulated by the D0 detector from April 2002 to April 2008 and corresponding to an integrated luminosity of 2.7 fb^{-1}. The events are reconstructed and selected following the criteria of an isolated lepton, missing transverse energy and two jets. The D0 Neural Network b-jet identification algorithm is further used to discriminate b jets from light jets. A multivariate analysis combining Matrix Element and Neural Network methods is explored to improve the Higgs boson signal significance. No evidence of the Higgs boson is observed in this analysis. In consequence, an observed (expected) limit on the ratio of σ (p$\\bar{p}$ → WH) x Br (H → b$\\bar{b}$) to the Standard Model prediction is set to be 6.7 (6.4) at 95% C.L. for the Higgs boson with a mass of 115 GeV.
Bosonization and even Grassmann variables
They test a new approach to bosonization in relativistic field theories and many-body systems, based on the use of fermionic composites as integration variables in the Berezin integral defining the partition function of the system. The method appears promising since at zeroth order it correctly describes the propagators of the composites, which can be evaluated in a number of significant cases. Still to be established is a general procedure for deriving the free action of the composites starting from the one of the constituents. To shed light on this problem and to explore further features of the method they study a simplified version of the BCS model. In this simple case the action of the composites can indeed be obtained: whether this result can be generalized it remains however to be seen. Yet an interesting property of the wave operators appearing in the free actions of bilinear composites already emerges from the simple problem they have treated: here the wave operators do not describe any time evolution, even though they generate the right propagators. This outcome relates to the basic properties of the integrals over the even elements of a Grassmann algebra where the composites live, which entails that the propagators are no longer the inverse of the wave operators
Search for an Invisibly Decaying Higgs Boson Produced via Vector Boson Fusion
AUTHOR|(SzGeCERN)661801
This thesis presents the first search of an invisibly decaying Higgs boson produced via Vector Boson Fusion on ATLAS. The dataset used for the analysis corresponds to 20.3fb$^{-1}$ of proton-proton collisions at $\\sqrt{s} = 8$ TeV recorded at the Large Hadron Collider in 2011 and 2012. An upper bound limit is set at 95% confidence level on the invisible branching fraction of the Higgs Boson. A limit of 28% is observed (34% expected) and interpreted using the Higgs portal model to set a limit on the dark matter-nucleon cross section. The unique jet final state created by Vector Boson Fusion provides a stronger signal to background ratio than other invisibly decaying Higgs channels. The Vector Boson Fusion analysis presented resulted in the strongest constraint on dark matter production set by a hadron collider.
Boson mapping and the microscopic collective nuclear Hamiltonian
Starting with the mapping of the quadrupole collective states in the fermion space onto the boson space, the fermion nuclear problem is transformed into the boson one. The boson images of the bifermion operators and of the fermion Hamiltonian are found. Recurrence relations are used to obtain approximately the norm matrix which appears in the boson-fermion mapping. The resulting boson Hamiltonian contains terms which go beyond the ordinary SU(6) symmetry Hamiltonian of the interacting boson model. Calculations, however, suggest that on the phenomenological level the differences between the mapped Hamiltonian and the SU(6) Hamiltonian are not too important. 18 refs.; 2 figs
Gumpert, Christian; The ATLAS collaboration
2016-01-01
The production of single Z bosons with two jets at high invariant mass has been studied by the ATLAS collaboration in detail using data corresponding to 20.3 /fb at a centre-of-mass energy of 8 TeV. Integrated and differential cross sections are measured in many different phase space regions with varying degree of sensitivity to the electroweak production in vector boson fusion. The cross section for the electroweak production has been extracted for both integrated and for the first time differential distributions. The results have also been used to derive limits on anomalous triple gauge couplings. Vector-boson scattering processes provide a unique way to probe the mechanism of electroweak symmetry breaking. Similar physics can be probed by studying the production of three gauge bosons. The results can also be used for a model-independent search for new physics at the TeV scale via anomalous quartic gauge couplings. The ATLAS collaboration has studied vector boson scattering in final states with two gauge bo...
Antonella Del Rosso
2012-01-01
A long-sought particle finally found. On Wednesday 4 July, enthusiasm spread from CERN to the worldwide media. But a question legitimately arises: why is this particle attracting so much interest? In other words, how is it different from all the others? (And, by the way, what is a boson?). CERN, 4 July 2012: a long-sought particle finally found. Strictly speaking, we cannot even call it the “Higgs” boson yet. Only after careful checking of its properties will physicists be able to say if the new boson corresponds to the particle that theorists predicted in 1964. However, the experimental data we have so far already tells us, unambiguously, that this new particle is different from all the other elementary particles we know. “Every particle is either a boson or a fermion,” explains John Ellis, former CERN theorist and currently professor at King's College in London. “All known particles spin like small tops, with the known bosons tha...
Interaction between bosonic dark matter and stars
Brito, Richard; Cardoso, Vitor; Macedo, Caio F. B.; Okawa, Hirotada; Palenzuela, Carlos
2016-02-01
We provide a detailed analysis of how bosonic dark matter "condensates" interact with compact stars, extending significantly the results of a recent Letter [1]. We focus on bosonic fields with mass mB , such as axions, axion-like candidates and hidden photons. Self-gravitating bosonic fields generically form "breathing" configurations, where both the spacetime geometry and the field oscillate, and can interact and cluster at the center of stars. We construct stellar configurations formed by a perfect fluid and a bosonic condensate, and which may describe the late stages of dark matter accretion onto stars, in dark-matter-rich environments. These composite stars oscillate at a frequency which is a multiple of f =2.5 ×1014(mBc2/eV ) Hz . Using perturbative analysis and numerical relativity techniques, we show that these stars are generically stable, and we provide criteria for instability. Our results also indicate that the growth of the dark matter core is halted close to the Chandrasekhar limit. We thus dispel a myth concerning dark matter accretion by stars: dark matter accretion does not necessarily lead to the destruction of the star, nor to collapse to a black hole. Finally, we argue that stars with long-lived bosonic cores may also develop in other theories with effective mass couplings, such as (massless) scalar-tensor theories.
Ratio method of measuring W boson mass
Guo, Feng [Stony Brook Univ., NY (United States)
2010-08-01
This dissertation describes an alternative method of measuring the W boson mass in DØ experiment. Instead of extracting M_{W} from the fitting of W → ev fast Monte Carlo simulations to W → ev data as in the standard method, we make the direct fit of transverse mass between W → ev data and Z → ee data. One of the two electrons from Z boson is treated as a neutrino in the calculation of transverse mass. In ratio method, the best fitted scale factor corresponds to the ratio of W and Z boson mass (M_{W}/M_{Z}). Given the precisely measured Z boson mass, W mass is directly fitted from W → ev and Z → ee data. This dissertation demonstrates that ratio method is a plausible method of measuring the W boson mass. With the 1 fb^{-1} DØ Run IIa dataset, ratio method gives M_{W} = 80435 ± 43(stat) ± 26(sys) MeV.
U boson at the BES III detector
The O(MeV) spin-1 U boson has been proposed to mediate the interaction among electron-positron and O(MeV) dark matter, in order to account for the 511 keV γ-ray observation by SPI/INTEGRAL. In this paper the observability of such a kind of U boson at BESIII is investigated through the processes e+e-→Uγ and e+e-→J/Ψ→e+e-U. We find that BESIII and high luminosity B factories have a comparable capacity to detect such a U boson. If the U boson decays mainly into dark matter, i.e. invisibly, BESIII can measure the coupling between the U boson and an electron-positron pair geR (see text) down to O(10-5), and cover large parameter space which can account for 511 keV γ-ray observation. On the other hand, provided that U decays mainly into the electron-positron, BESIII can detect geR down to O(10-3), and it is hard to explore the 511 keV γ-ray measurement allowed parameter space due to the irreducible QED backgrounds
ATLAS measurements of vector boson production
Debenedetti, Chiara; The ATLAS collaboration
2016-01-01
Vector boson production in pp collisions at 7, 8 and 13 TeV has been extensively studied by ATLAS. Recent results include the precision measurements of the transverse momentum of the Z/gamma* boson production, sensitive to soft resummation effects, hard jet emissions and electroweak corrections. A precise measurement of the angular coefficients of the Zboson production tests the underlying QCD dynamics of the DrellYan process. A first measurement of the inclusive W and Z cross section at a cms energy of 13TeV has been derived. The Production of jets in association with a vector boson is an important process to study QCD in a multiscale environment. Cross sections, differential in several kinematics variables, have been measured with the ATLAS detector and compared to stateoftheart QCD calculations and Monte Carlo simulations. First measurements of vector boson + jets production have been performed at cms energies of 13TeV. An overview of these results is given.
Scattering problem for four-boson system
The s-wave phase shift of boson-triboson scattering has been obtained by solving the Faddeev-Osborn equation in the exact approach based on rigorous Faddeev theory. The Schmidt expansion theorem is used to express the 3+1- and 2+2-subamplitudes at energies in the continuous spectrum region as an infinite series of separable terms. Employing the pole term decomposition for these subamplitudes expressed in terms of the Schmidt expansion we can define, in conformity with the Faddeev residue prescription, respective four-nucleon amplitudes that describe elastic/rearrangement, partial breakup and full breakup scattering processes. Acquired simultaneous equations of these amplitudes take the form of multichannel two-particle Lippmann-Schwinger type, which we call Faddeev-Osborn equation. Assuming as an s-wave spin-independent, rank one separable potential of the Yamaguchi type for the two-particle interaction, are derived the Faddeev-Osborn equation for the boson-triboson elastic scattering. To treat singularities appeared in our equation, the numerical calculation is performed in the framework of the complex-valued analysis by introducing contour rotation method. The boson-triboson elastic scattering amplitude for L=0 state of a four-boson system is obtained numerically in the incident boson laboratory energy region of 0.01-24.0 Mev, including only 1=0 state for the 3+1-subamplitude. The results of the phase shift obtained from the amplitudes are plotted as dots in Fig. 1. (author)
Ratio method of measuring $w$ boson mass
Guo, Feng; /SUNY, Stony Brook
2010-08-01
This dissertation describes an alternative method of measuring the W boson mass in D0 experiment. Instead of extracting M{sub W} from the fitting of W {yields} e{nu} fast Monte Carlo simulations to W {yields} e{nu} data as in the standard method, we make the direct fit of transverse mass between W {yields} e{nu} data and Z {yields} ee data. One of the two electrons from Z boson is treated as a neutrino in the calculation of transverse mass. In ratio method, the best fitted scale factor corresponds to the ratio of W and Z boson mass (M{sub W}/M{sub Z}). Given the precisely measured Z boson mass, W mass is directly fitted from W {yields} e{nu} and Z {yields} ee data. This dissertation demonstrates that ratio method is a plausible method of measuring the W boson mass. With the 1 fb{sup -1} D0 Run IIa dataset, ratio method gives M{sub W} = 80435 {+-} 43(stat) {+-} 26(sys) MeV.
Correlations in charged bosons systems
The two and three-dimensional charge Bose gas have been studied. In the bidimensional case two different types of interaction were considered: l/r and l n(r). The method of self-consistent-field was applied to these systems, which takes into account the short range correlations between the bosons through a local-field correction. By using self-consistent numerical calculations, the structure factor S(k→) was determined. The pair-correlation function, the ground-state energy, the pressure of the gas and the spectrum of elementary excitations were obtained from S (k→). The screening density induced by a fixed charged impurity was calculated. In the high-density limit our calculations reproduce the results given by Bogoliubov's perturbation theory. In the intermediate-density region, corresponding to the strongly coupled systems, the results are in very good agreement with calculations based on HNC approximation as well as Monte Carlo method. The results are compared in several situations with RPA results showing that the self-consistent method is much more accurate. The two-dimensional systems showed to be more correlated than the three-dimensional systems showed to be more correlated than the three-dimensional one; the gas with interaction l/r is also more correlated than the logarithmic one at high densities, but it begins to be less correlated than this one in the low-density region. The thermodynamic functions of the two and three-dimensional systems at finite temperatures near absolute zero are calculated based upon the gas excitation spectra at zero temperature. (author)
Orbital optical lattices with bosons
Kock, T.; Hippler, C.; Ewerbeck, A.; Hemmerich, A.
2016-02-01
This article provides a synopsis of our recent experimental work exploring Bose-Einstein condensation in metastable higher Bloch bands of optical lattices. Bipartite lattice geometries have allowed us to implement appropriate band structures, which meet three basic requirements: the existence of metastable excited states sufficiently protected from collisional band relaxation, a mechanism to excite the atoms initially prepared in the lowest band with moderate entropy increase, and the possibility of cross-dimensional tunneling dynamics, necessary to establish coherence along all lattice axes. A variety of bands can be selectively populated and a subsequent thermalization process leads to the formation of a condensate in the lowest energy state of the chosen band. As examples the 2nd, 4th and 7th bands in a bipartite square lattice are discussed. The geometry of the 2nd and 7th bands can be tuned such that two inequivalent energetically degenerate energy minima arise at the X ±-points at the edge of the 1st Brillouin zone. In this case even a small interaction energy is sufficient to lock the phase between the two condensation points such that a complex-valued chiral superfluid order parameter can emerge, which breaks time reversal symmetry. In the 4th band a condensate can be formed at the Γ-point in the center of the 1st Brillouin zone, which can be used to explore topologically protected band touching points. The new techniques to access orbital degrees of freedom in higher bands greatly extend the class of many-body scenarios that can be explored with bosons in optical lattices.
Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs
Viel, Alexandra; Simoni, Andrea
2016-01-01
We study theoretically magnetically induced Feshbach resonances and near-threshold bound states in isotopic NaK pairs. Our calculations accurately reproduce Feshbach spectroscopy data on Na$^{40}$K and explain the origin of the observed multiplets in the p-wave [Phys. Rev. A 85, 051602(R) (2012)]. We apply the model to predict scattering and bound state threshold properties of the boson-boson Na$^{39}$K and Na$^{41}$K systems. We find that the Na$^{39}$K isotopic pair presents broad magnetic ...
Hexadecapole degree of freedom in the interacting boson model
The hexadecapole degree of freedom in the interacting boson models with sd and sdg bosons is reviewed with the aim of providing experimental signatures that distinguish between the two models. (orig.)
Bosonic Dp-branes at finite temperature in TFD approach
Abdalla, M. C. B.; Gadelha, A. L.; Vancea, I. V.
2004-02-01
A general formulation of Thermo Field Dynamics using transformation generators that form the SU(1, 1) group, is presented and applied to the closed bosonic string and for bosonic Dp-brane with an external field.
Bosonic Dp-branes at finite temperature in TFD approach
Abdalla, M.C.B.; Gadelha, A.L.; Vancea, I.V
2004-02-01
A general formulation of Thermo Field Dynamics using transformation generators that form the SU(1, 1) group, is presented and applied to the closed bosonic string and for bosonic D{sub p}-brane with an external field.
Bosonic Dp-branes at finite temperature in TFD approach
A general formulation of Thermo Field Dynamics using transformation generators that form the SU(1, 1) group, is presented and applied to the closed bosonic string and for bosonic Dp-brane with an external field
Higgs bosons in the standard model, the MSSM and beyond
John F Gunion
2004-02-01
I summarize the basic theory and selected phenomenology for the Higgs boson(s) of the standard model, the minimal supersymmetric model and some extensions thereof, including the next-to-minimal supersymmetric model.
Integrability and Quantum Phase Transitions in Interacting Boson Models
Dukelsky, J; García-Ramos, J E; Pittel, S
2003-01-01
The exact solution of the boson pairing hamiltonian given by Richardson in the sixties is used to study the phenomena of level crossings and quantum phase transitions in the integrable regions of the sd and sdg interacting boson models.
Search for a Higgs Boson Produced in Association with a W Boson at ATLAS
Ruckert, Benjamin
The Large Hadron Collider at CERN is the most modern proton-proton collider and data taking will start in 2009, with a centre-of-mass energy of 7 TeV. The ATLAS detector, which is one of two multi-purpose detectors at the Large Hadron Collider, is able to detect a Standard Model Higgs boson if it exists. This is one of the main tasks of the ATLAS experiment. This thesis deals with a Standard Model Higgs boson produced in association with a W boson. The Monte Carlo study is based on physics events generated at the nominal centre-of-mass energy of the Large Hadron Collider of 14 TeV. Large parts of this analysis have been done using the global Grid infrastructure of the Large Hadron Collider experiments. A mass range of the Higgs boson of mH = 130 - 190 GeV has been taken into account. In this mass range, the Higgs boson dominantly decays into a pair of W bosons, leading to initially three W bosons: WH -> WWW. Two orthogonal analysis channels have been investigated in detailed studies of the background properti...
Bosonization of Weyl Fermions and Free Electrons
Marino, E C
2015-01-01
The electron, discovered by Thomson by the end of the nineteenth century, was the first experimentally observed particle. The Weyl fermion, though theoretically predicted since a long time, was observed in a condensed matter environment in an experiment reported only a few weeks ago. Is there any linking thread connecting the first and the last observed fermion (quasi)particles? The answer is positive. By generalizing the method known as bosonization, the first time in its full complete form, for a spacetime with 3+1 dimensions, we are able to show that both electrons and Weyl fermions can be expressed in terms of the same boson field, namely the Kalb-Ramond anti-symmetric tensor gauge field. The bosonized form of the Weyl chiral currents lead to the angle-dependent magneto-conductance behavior observed in these systems.
Light gauge boson in rare $K$ decay
Chen, Chuan-Hung
2016-01-01
The inconsistent conclusions for a light gauge boson $X$ production in the $K^- \\to \\pi^- X$ exist in the literature. It is found that the process can be generated by the tree-level $W$-boson annihilation and loop-induced $s\\to dX$. We find that it strongly depends on the $SU(3)$ limit or the unique gauge coupling to the quarks, whether the $K^-\\to \\pi^- X$ decay, which is from the $W$-boson annihilation, is suppressed by $m^2_X \\epsilon_X \\cdot p_K$; however, no such suppression is found via the loop-induced $s\\to d X$. The constraints on the relevant couplings are studied.
Abbiendi, G; Åkesson, P F; Alexander, G; Allison, J; Amaral, P; Anagnostou, G; Anderson, K J; Arcelli, S; Asai, S; Axen, D A; Azuelos, Georges; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Büsser, K; Burckhart, H J; Campana, S; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Couchman, J; Csilling, Akos; Cuffiani, M; Dado, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, Franco Luigi; Feld, L; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Gaycken, G; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanaya, N; Kanzaki, J; Karlen, Dean A; Kawagoe, K; Kawamoto, T; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Klein, K; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krieger, P; Von Krogh, J; Krüger, K; Kühl, T; Kupper, M; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Layter, J G; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Masetti, G; Mashimo, T; Mättig, P; McKenna, J A; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Moed, S; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Okpara, A N; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Poli, B; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rosati, S; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Waller, D; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wetterling, D; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L
2004-01-01
Elements of the spin density matrix for W bosons in e+e- -> W+W- -> qqln events are measured from data recorded by the OPAL detector at LEP. This information is used calculate polarised differential cross-sections and to search for CP-violating effects. Results are presented for W bosons produced in e+e- collisions with centre-of-mass energies between 183 GeV and 209 GeV. The average fraction of W bosons that are longitudinally polarised is found to be (23.9 +- 2.1 +- 1.1)% compared to a Standard Model prediction of (23.9 +- 0.1)%. All results are consistent with CP conservation.
Efficient experimental validation of photonic boson sampling
Spagnolo, N; Bentivegna, M; Brod, D J; Crespi, A; Flamini, F; Giacomini, S; Milani, G; Ramponi, R; Mataloni, P; Osellame, R; Galvao, E F; Sciarrino, F
2013-01-01
A boson sampling device is a specialised quantum computer that solves a problem which is strongly believed to be computationally hard for classical computers. Recently a number of small-scale implementations have been reported, all based on multi-photon interference in multimode interferometers. In the hard-to-simulate regime, even validating the device's functioning may pose a problem. In a recent criticism of boson sampling experiments, Gogolin et al. argued that the output would be effectively indistinguishable from the trivial, uniform distribution. Here we report new boson sampling experiments on larger photonic chips, and analyse the data using a scalable statistical test recently proposed by Aaronson and Arkhipov. We show the test successfully validates small experimental data samples against the hypothesis that they are uniformly distributed. We also show how to discriminate data arising from either indistinguishable or distinguishable photons. Our results pave the way towards demonstrating the quantu...
Microscopic approach to the interacting boson model
A method is outlined for analyzing the interacting boson model microscopically in terms of S- and D-fermion pairs. We derive the number operator approximation (NOA) of Otsuka and Arima by considering functions that generate normalizations and matrix elements of states built of S-pairs. An extension of the formalism leads to a generalization of the NOA including both S and D. This approximation is suggested as a starting point for determining the collective SD subspace in a dynamical way. The simplified fermion problem that results from restriction of the hamiltonian to the SD subspace can be mapped onto a corresponding sd boson problem. Due to the finiteness of the spermion space, and the non-orthogonality of the collective SD basis, the boson hamiltonian obtained is non-hermitian. (orig.)
Fidelities in the spin-boson model
Lukyanov, Sergei L.
2016-04-01
The spin-boson model (or the dissipative two-state system) is a model for the study of dissipation and decoherence in quantum mechanics. The spin-boson model with Ohmic dissipation is an integrable theory, related to several other integrable systems including the anisotropic Kondo and resonant level models. Here we consider the problem of computing the overlaps between two ground states corresponding to different values of parameters of the Ohmic spin-boson Hamiltonian. We argue that this can be understood as a part of the problem of quantizing the mKdV/sine-Gordon integrable hierarchy. The main objective of this work is to analyze how the Anderson orthogonality affects the Yang-Baxter integrable structure underlying the theory.
QCD corrections to Higgs boson decays
The two-loop OMIKRON (αsGFmt2) corrections to the b anti b decay rate of the Standard Model Higgs boson as well as its production via e+e-→ZH will be presented. These QCD corrections are obtained by using a low-energy theorem for light Higgs bosons compared to the top quark mass. The results yield strong screening effects of the OMIKRON (GFmt2) contributions. After that the two-loop QCD corrections to the γγ and gluonic decays of the Higgs bosons of the Standard Model and its minimal supersymmetric extension are discussed. While the corrections to the γγ decays remain small of OMIKRON (αs) they are huge ∝50-70% in the case of the gluonic decays. (orig.)
Improved effective vector boson approximation revisited
Bernreuther, Werner; Chen, Long
2016-03-01
We reexamine the improved effective vector boson approximation which is based on two-vector-boson luminosities Lpol for the computation of weak gauge-boson hard scattering subprocesses V1V2→W in high-energy hadron-hadron or e-e+ collisions. We calculate these luminosities for the nine combinations of the transverse and longitudinal polarizations of V1 and V2 in the unitary and axial gauge. For these two gauge choices the quality of this approach is investigated for the reactions e-e+→W-W+νeν¯ e and e-e+→t t ¯ νeν¯ e using appropriate phase-space cuts.
Critical Scaling and a Dynamical Higgs Boson
Mannheim, Philip D
2016-01-01
In a quantum electrodynamics theory that is realized by critical scaling and anomalous dimensions, even though the fermion mass is generated dynamically, the Lagrangian is not chiral invariant and no dynamical pseudoscalar Goldstone boson or scalar Higgs boson accompanies the mass generation. In the mean-field approximation to a chiral invariant four-fermion theory there is also dynamical mass generation. However, the associated mean-field sector Lagrangian is not chirally invariant and possesses no dynamical bound states, with Goldstone and Higgs boson bound states instead being generated by the residual interaction. In this paper we show that if a critical scaling electrodynamics is augmented with a four-fermion interaction, precisely because it possesses no dynamical bound states the electrodynamic sector can be reinterpreted as a mean-field approximation to a larger theory that is chiral symmetric, and in this larger theory there is a residual interaction that then does generate dynamical Goldstone and Hi...
Buchel, Alex; Lehner, Luis
2013-01-01
We construct boson stars in global Anti de Sitter (AdS) space and study their stability. Linear perturbation results suggest that the ground state along with the first three excited state boson stars are stable. We evolve some of these solutions and study their nonlinear stability in light of recent work \\cite{Bizon:2011gg} arguing that a weakly turbulent instability drives scalar perturbations of AdS to black hole formation. However evolutions suggest that boson stars are nonlinearly stable and immune to the instability for sufficiently small perturbation. Furthermore, these studies find other families of initial data which similarly avoid the instability for sufficiently weak parameters. Heuristically, we argue that initial data families with widely distributed mass-energy distort the spacetime sufficiently to oppose the coherent amplification favored by the instability. From the dual CFT perspective our findings suggest that there exist families of rather generic initial conditions in strongly coupled CFT ...
The general boson normal ordering problem
Blasiak, P; Solomon, A I; Blasiak, Pawel; Penson, Karol A.; Solomon, Allan I.
2003-01-01
We solve the boson normal ordering problem for F[(a*)^r a^s], with r,s positive integers, where a* and a are boson creation and annihilation operators satisfying [a,a*]=1. That is, we provide exact and explicit expressions for the normal form wherein all a's are to the right. The solution involves integer sequences of numbers which are generalizations of the conventional Bell and Stirling numbers whose values they assume for r=s=1. A comprehensive theory of such generalized combinatorial numbers is given including closed-form expressions (extended Dobinski-type formulas)and generating functions. These last are special expectation values in boson coherent states.
Triplet Higgs boson at hadron colliders
The novel feature of a Higgs-triplet representation is a nonzero tree-level coupling of H+W-Z, which is absent in all Higgs-doublet models. We study the associated production of a singly-charged Higgs boson of the Higgs-triplet representation with a W or Z boson at hadron colliders, followed by the H+→W+Z decay. We find that the 2l+4j final state gives an interesting level of signal with a negligible background, plus it allows a full mass reconstruction of the charged-Higgs boson. The cover range of the charged-Higgs mass is between 110 and 200 GeV. (author)
Elementary Goldstone Higgs Boson and Dark Matter
Alanne, Tommi; Gertov, Helene; Sannino, Francesco;
2015-01-01
We investigate a perturbative extension of the Standard Model featuring elementary pseudo-Goldstone Higgs and dark matter particles. These are two of the five Goldstone bosons parametrising the SU(4)/Sp(4) coset space. They acquire masses, and therefore become pseudo-Goldstone bosons, due...... of the theory, the quantum corrections are precisely calculable. The remaining pseudo-Goldstone boson is identified with the dark matter candidate because it is neutral with respect to the Standard Model and stable. By a direct comparison with the Large Hadron Collider experiments, the model is found...... to be phenomenologically viable. Furthermore the dark matter particle leads to the observed thermal relic density while respecting the most stringent current experimental constraints....
Cascade Decays of Triplet Higgs Bosons at LEP2
Akeroyd, A G
1998-01-01
We study the Georgi-Machacek two triplet, one doublet model in the context of LEP2, and show that cascade decays of Higgs bosons to lighter Higgs bosons and a virtual vector boson may play a major role. Such decays would allow the Higgs bosons of this model to escape current searches, and in particular are of great importance for the members of the five-plet which will always decay to the three-plet giving rise to cascade signatures.
NLO QCD corrections to Wγ production via vector boson fusion
Vector boson fusion processes will be used to probe the mechanism of electroweak symmetry breaking at the LHC. Wγ production via vector boson fusion is expected to yield important information on triple and quartic vector boson couplings. We have implemented the full next-to-leading order QCD corrections to Wγ production via vector boson fusion in a flexible parton-level Monte Carlo program, VBFNLO. Here we present our results.
The Physics of New U(1)' Gauge Bosons
Langacker, Paul
2009-01-01
Additional Z' gauge bosons are predicted by a wide variety of extensions of the standard model (SM). Possibilities include TeV-scale bosons with electroweak coupling, very light bosons which nearly decouple from the standard model particles, and bosons which communicate with a quasi-hidden sector. A broad survey is given of the theoretical possibilities and of the physics implications for particle physics and cosmology. Several novel examples, including light Z's suggested by PAMELA, Stueckel...
Standard electroweak interactions and Higgs bosons
Cox, B.; Gilman, F.J.
1984-09-01
In the standard model, only one basic component remains to be found: the Higgs boson. The specifics of Higgs boson production and detection, with decay to t anti t and a particular t quark mass range in mind, have not been examined in detail. As such, the working group on Standard Electroweak Interactions and Higgs Bosons at this meeting decided to concentrate on Higgs boson production and detection at SSC energies in the particular case where the Higgs mass is in the range so as to make t anti t quark-antiquark pairs the dominant decay mode. The study of this case, that of the so-called intermediate mass Higgs, had already been launched in the Berkeley PSSC Workshop on Electroweak Symmetry Breaking, and was continued and extended here. The problems of t quark jet identification and detection efficiency and the manner of rejection of background (especially from b quark jets) with realistic detectors then occupied much of the attention of the group. The subject of making precise measurements of parameters in the standard model at SSC energies is briefly examined. Then we delve into the Higgs sector, with an introduction to the neutral Higgs of the standard model together with its production cross-sections in various processes and the corresponding potential backgrounds. A similar, though briefer, discussion for a charged Higgs boson (outside the Standard Model) follows. The heart of the work on identifying and reconstructing the t and then the Higgs boson in the face of backgrounds is discussed. The problems with semileptonic decays, low energy jet fragments, mass resolution, and b-t discrimination all come to the fore. We have tried to make a serious step here towards a realistic assessment of the problems entailed in pulling a signal out of the background, including a rough simulation of calorimeter-detector properties. 25 references.
Higgs boson couplings to bosons with the ATLAS detector: Run 1 legacy
Petit, E.; Atlas Collaboration
2016-07-01
The final ATLAS measurements of Higgs boson production and couplings in the decay channels H → ZZ^{(*)} → ℓℓℓℓ , H → γγ and H → WW(*) → ℓ νℓ ν are presented, based on the run 1 of the LHC. The analyses are optimised to measure the number of observed Higgs boson decays divided by the corresponding Standard Model predictions for individual Higgs boson production processes. Total, fiducial and differential cross-sections are also measured. No significant deviations from the predictions of the Standard Model are found.
Neutral Higgs boson search at Tevatron
Yao, Wei-Ming; /LBL, Berkeley
2004-11-01
The authors review searches for neutral Higgs Boson performed by the CDF and D0 collaborations using approximately 200 pb{sup -1} of the dataset accumulated from p{bar p} collisions at the center-of-mass energy of 1.96 TeV. No signals are found and limits on the Standard Model (SM) Higgs or SM-like Higgs production cross section times branching ratio and couplings of the Higgs boson in MSSM are presented, including the future prospects of discovery Higgs at the end of Run II.
Bosonic superconformal algebras from hamiltonian reduction
Hamiltonian reduction of WZW theories involving constraints with half integer conformal weight is analyzed. The reduced system can be described in terms of an effective action that corresponds to a generalized Toda system. To obtain this action, the constraints must be imposed on an enlarged phase space that includes weight 1/2 bosons in addition to the WZW degrees of freedom. An example is worked out for which the chiral algebra consists of a bosonic version of the uN extended superconformal algebra. A Gauss decomposition of the WZW field leads to a hybrid free field realization of these algebras. (orig.)
Slepton production from gauge boson fusion
Choudhury, D; Huitu, K; Konar, P; Moretti, S; Mukhopadhyaya, B; Choudhury, Debajyoti; Datta, Anindya; Huitu, Katri; Konar, Partha; Moretti, Stefano; Mukhopadhyaya, Biswarup; 10.1103/PhysRevD.68.075007
2003-01-01
We emphasise that charged slepton pairs produced via vector-boson fusion along with two high-mass, high-$p_T$ forward/backward jets (in two opposite hemispheres) can have a higher production cross-section for heavy slepton masses than that from conventional Drell-Yan production at a hadronic collider like the LHC. We analyse the signal and leading backgrounds in detail in the minimal supersymmetric standard model with conserved baryon and lepton numbers. Our investigation reveals that the mass reach of the vector-boson fusion channel is certainly an improvement over the scope of the Drell-Yan mode.
Lepton flavor violation with light vector bosons
Heeck, Julian
2016-07-01
New sub-GeV vector bosons with couplings to muons but not electrons have been discussed in order to explain the muon's magnetic moment, the gap of high-energy neutrinos in IceCube or the proton radius puzzle. If such a light Z‧ not only violates lepton universality but also lepton flavor, as expected for example from the recent hint for h → μτ at CMS, the two-body decay mode τ → μZ‧ opens up and for MZ‧ vector bosons with lepton-flavor-violating couplings.
Gauge boson production at the Tevatron
Cecilia E Gerber
2003-01-15
We present measurements on gauge boson production from data taken during 1994-1996 by the D0 and CDF detectors: the differential production cross section of the W boson as a function of the transverse momentum [1,2], the ratio of W and Z differential cross sections [3,4], direct photon cross-sections at {radical}s = 630 and 1800 GeV [5,6], and studies of Drell-Yan production [7,8]. All measurements are in good agreement with currently available theoretical predictions in most of the measured kinematic range.
Higgs boson decays in the Complex MSSM
Williams, K. E.; Weiglein, G.
2007-01-01
The analysis of the Higgs search results at LEP showed that a part of the MSSM parameter space with non-zero complex phases could not be excluded, where the lightest neutral Higgs boson, h_1, has a mass of only about 45 GeV and the second lightest neutral Higgs boson, h_2, has a sizable branching fraction into a pair of h_1 states. Full one-loop results for the Higgs cascade decay h_2 --> h_1 h_1 are presented and combined with two-loop Higgs propagator corrections taken from the program Feyn...
Higgs boson mass from gauge invariant operators
Jora, Renata
2016-01-01
We make the assumption that the vacuum correlators of the gauge invariant kinetic term of the Higgs doublet are the same before and after the spontaneous symmetry breaking of the theory. Based on this we determine the mass of the standard model Higgs boson at $m_h \\approx 125.07$ GeV by considering one loop and the most relevant two loop corrections. This result might suggest that there is a single Higgs boson doublet that contributes to the electroweak symmetry breaking.
Lepton flavor violation with light vector bosons
Heeck, Julian
2016-07-01
New sub-GeV vector bosons with couplings to muons but not electrons have been discussed in order to explain the muon's magnetic moment, the gap of high-energy neutrinos in IceCube or the proton radius puzzle. If such a light Z‧ not only violates lepton universality but also lepton flavor, as expected for example from the recent hint for h → μτ at CMS, the two-body decay mode τ → μZ‧ opens up and for MZ‧ year-old ARGUS limits. We discuss the general prospects and motivation of light vector bosons with lepton-flavor-violating couplings.
Search for Charged Higgs Bosons at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosenbleck, C; Rosier-Lees, S; Roth, S; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2003-01-01
A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at centre-of-mass energies between 189 and 209GeV, corresponding to an integrated luminosity of 629.4/pb. Decays into a charm and a strange quark or into a tau lepton and its neutrino are considered. No significant excess is observed and lower limits on the mass of the charged Higgs boson are derived at the 95% confidence level. They vary from 76.5 to 82.7GeV, as a function of the H->tv branching ratio.
Z Boson Pair-Production at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Roux, B; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2003-01-01
Events stemming from the pair-production of Z bosons in e^+e^- collisions are studied using 217.4 pb^-1 of data collected with the L3 detector at centre-of-mass energies from 200 GeV up to 209 GeV. The special case of events with b quarks is also investigated. Combining these events with those collected at lower centre-of-mass energies, the Standard Model predictions for the production mechanism are verified. In addition, limits are set on anomalous couplings of neutral gauge bosons and on effects of extra space dimensions.
Searches for BSM Higgs Bosons with ATLAS
Navarro, Gabriela; The ATLAS collaboration
2015-01-01
The discovery of a Higgs-like boson with a mass of about 125GeV has prompted the question of whether or not this particle is part of a much larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS Experiment regarding Beyond-the-Standard Model (BSM) Higgs hypothesis tests are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal Supersymmetric Standard Model.
The discovery of the intermediate vector bosons
The discovery of the intermediate vector bosons in 1983 at CERN marked the culmination of a long effort to unify the theory of weak and electromagnetic forces. Here a brief outline of development of the electroweak theory which unifies these forces is given first. Its essential feature is the prediction of the existence of the W+- and Z0 bosons with rest masses of about ninety times the proton mass and lifetimes around 10-24s. Then the experimental methods used at CERN to produce and to detect these very massive and short-lived particles are described. (author)
Left and right handedness of fermions and bosons
It is shown, by using Grassmann space to describe the internal degrees of freedom of fermions and bosons, that the Weyl-like equation exists not only for massless fermions but also for massless vector bosons. The corresponding states have well defined helicity and handedness. It is also shown that spinors and vector bosons interact only if both are of the same handedness. (author)
Momentum-space calculation of four-boson recombination
Deltuva, A.
2012-01-01
The system of four identical bosons with large two-boson scattering length is described using momentum-space integral equations for the four-particle transition operators. The creation of Efimov trimers via ultracold four-boson recombination is studied. The universal behavior of the recombination rate is demonstrated.
YANG Jin; YU Wan-Lun; XIANG An-Ping
2006-01-01
We use Lewis-Riesenfeld invariant approach to treat the modified Jaynes-Cummings models involving any forms of nonlinearty of the bosonic field when strong boson-fermion couplings are nilpotent Grassmann valued. The general state functions, time evolution operator and the time-evolution expressions for both the bosonic number and the fermionic number are presented.
Search for an Invisibly Decaying Higgs Boson Produced via Vector Boson Fusion with ATLAS
Bassalat, Ahmed; The ATLAS collaboration
2015-01-01
The recently discovered Higgs boson at a mass 125 GeV provides an excellent tool to probe beyond the Standard Model physics. Many extensions of the Standard Model predict the decay of the Higgs boson into weakly interacting or neutral particles which do not interact with the detector, that could be candidates for dark matter. Using proton-proton collision data collected by the ATLAS detector during Run 1, searches have been performed for an invisibly decaying Higgs boson in three production channels: via vector boson fusion (VBF). An upper bound of 0.28 is set on the branching fraction of H -> invisible at 95% confidence level, where the expected upper limit is 0.31. The results are interpreted in models of Higgs-portal dark matter and of supersymmetry with a compressed mass spectrum.
Distinguishing Various Models of the 125 GeV Boson in Vector Boson Fusion
Chang, Jung; Tseng, Po-Yan; Yuan, Tzu-Chiang
2012-01-01
The hint of a new particle around 125 GeV at the LHC through the decay modes of diphoton and a number of others may point to quite a number of possibilities. While at the LHC the dominant production mechanism in the standard model is via the gluon fusion process, the alternative vector boson fusion is more sensitive to electroweak symmetry breaking through the $WWh$ and $ZZh$ couplings and therefore can be used to probe for models beyond the standard model. In this work, using the well known dijet-tagging technique to single out the vector boson fusion mechanism, we investigate its capability to discriminate a number of models, including the standard model Higgs boson, fermiophobic Higgs boson, Randall-Sundrum radion, inert-doublet-Higgs model, two-Higgs-doublet model, and selective benchmark points of MSSM and NMSSM.
Measurement of Triple-Gauge-Boson Couplings of the W Boson at LEP
Acciarri, M; Adriani, O; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Balandras, A; Ball, R C; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brigljevic, V; Brochu, F; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Button, A M; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Coignet, G; Colijn, A P; Colino, N; Costantini, S; Cotorobai, F; Cozzoni, B; de la Cruz, B; Csilling, Akos; Cucciarelli, S; Dai, T S; van Dalen, J A; D'Alessandro, R; De Asmundis, R; Déglon, P L; Degré, A; Deiters, K; Della Volpe, D; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Duensing, S; Dufournaud, D; Duinker, P; Durán, I; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Extermann, Pierre; Fabre, M; Faccini, R; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hidas, P; Hirschfelder, J; Hofer, H; Holzner, G; Hoorani, H; Hou, S R; Iashvili, I; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Khan, R A; Kamrad, D; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Kräber, M H; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lassila-Perini, K M; Laurikainen, P; Lavorato, A; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Lugnier, L; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Marchesini, P A; Marian, G; Martin, J P; Marzano, F; Massaro, G G G; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Molnár, P; Monteleoni, B; Moulik, T; Muanza, G S; Muheim, F; Muijs, A J M; Musy, M; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nisati, A; Nowak, H; Oh, Yu D; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Paramatti, R; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Pothier, J; Produit, N; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Raven, G; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schopper, Herwig Franz; Schotanus, D J; Schwering, G; Sciacca, C; Sciarrino, D; Seganti, A; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stone, H; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Suter, H; Swain, J D; Szillási, Z; Sztaricskai, T; Tang, X W; Tauscher, Ludwig; Taylor, L; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Uchida, Y; Ulbricht, J; Valente, E; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, M; Wang, X L; Wang, Z M; Weber, A; Weber, M; Wienemann, P; Wilkens, H; Wu, S X; Wynhoff, S; Xia, L; Xu, Z Z; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Ye, J B; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhu, G Y; Zhu, R Y; Zichichi, A; Ziegler, F; Zilizi, G; Zöller, M
1999-01-01
We report on measurements of the triple-gauge-boson couplings of the W boson in $\\mathrm{e^+e^-}$ collisions with the L3 detector at LEP. W-pair, single-W and single-photon events are analysed in a data sample corresponding to a total luminosity of 76.7~pb$^{-1}$ collected at centre-of-mass energies between 161~GeV and 183~GeV. CP-conserving as well as both C- and P-conserving triple-gauge-boson couplings are determined. The results, in good agreement with the Standard-Model expectations, confirm the existence of the self coupling among the electroweak gauge bosons and constrain its structure.
Search for doubly charged Higgs bosons through vector boson fusion at the LHC and beyond
Bambhaniya, G.; Chakrabortty, J.; Gluza, J.; Jeliński, T.; Szafron, R.
2015-07-01
Production and decays of doubly charged Higgs bosons at the LHC and future hadron colliders triggered by a vector boson fusion mechanism are discussed in the context of the minimal left-right symmetric model. Our analysis is based on the Higgs boson mass spectrum compatible with available constraints which include flavor changing neutral current (FCNC) effects and vacuum stability of the scalar potential. Though the parity breaking scale vR is large (˜ few TeV) and scalar masses which contribute to FCNC effects are even larger, a consistent Higgs boson mass spectrum still allows us to keep doubly charged scalar masses below 1 TeV which is an interesting situation for LHC and future circular collider (FCC). We have shown that the allowed Higgs boson mass spectrum constrains the splittings (MH1±±-MH1± ), closing the possibility of H1±±→W1±H1± decays. Assuming that doubly charged Higgs bosons decay predominantly into a pair of same-sign charged leptons through the process p p →H1/2 ±±H1/2 ∓∓j j →ℓ±ℓ±ℓ∓ℓ∓j j , we find that for the LHC operating at √{s }=14 TeV with an integrated luminosity at the level of 3000 fb-1 (HL-LHC), there is practically no chance to detect such particles at the reasonable significance level through this channel. However, at 33 TeV HE-LHC and (or) 100 TeV FCC-hh, a wide region opens up for exploring the doubly charged Higgs boson mass spectrum. In FCC-hh, the doubly charged Higgs bosons mass up to 1 TeV can be easily probed.
Vector boson self-interactions and vector boson production within the BESS-model
Predictions of the BESS model were calculated for e+e-→W+W- and for e+e-→ three gauge bosons (W+W-Z, W+W-γ, ZZZ, ZZγ, Zγγ, γγγ) processes. Total cross sections and angular distributions both for unpolarized and polarized final vector bosons and the angular asymmetries were calculated. The results are compared with Standard Model predictions. (K.A.) 11 refs., 5 figs
Interacting vector boson model and other versions of IBM
The Dyson mapping of interacting vector boson model (IVBM) on the standard IBM with dynamical symmetry U(21) is obtained. This version of IBM contains the S(T=1), D(T=1) and P(T=0) bosons, where T is isospin of bosons. From group theory view point it corresponds to the realization of the Sp(12,R) generators in terms of generators of HW(21)xU(6) group. The problem of elimination of spurious states and Hermitization of this boson representation is discussed. The image of the IVBM Hamiltonian in the space of above mentioned S, D, P-bosons is found. 22 refs
D0 Search for the Higgs Boson in Multijet Events
Melnitchouk, Alex; Collaboration, for the D0
2006-01-01
We present two searches for the Higgs boson in \\sqrt{s} = 1.96 TeV p\\bar{p}collisions using data taken with the \\dz detector during Run II of the Fermilab Tevatron collider. The first study is a search for neutral Higgs bosons produced in association with bottom quarks. We set upper limits on the production of neutral Higgs bosons in the mass range of 90 to 150 GeV.The second study is a search for the standard model Higgs boson produced in association with the Z boson. We study the p\\bar{p}\\t...
Selection of collective degrees of freedom in the boson space
Two methods for selecting collective bosons, one proposed by Klein and Vallieres and the other one being a number conserved Tamm Dancoff method, are applied in this work to boson mapping methods. The first mapping to be tested is a Dyson boson mapping in the SD shell and the second one is a mapping developed by Bonatsos, Klein and Li and applied to two j-shells with |j1 - j2| = 4. Whenever the boson mappings are accurate, the selection of collective bosons gives good results, independently of the method considered. (author)
NLO vector boson production with light jets
Bern, Z; Dixon, L J; Cordero, F Febres; Forde, D; Gleisberg, T; Hoeche, S; Ita, H; Kosower, D A; Maitre, D; Ozeren, K
2012-01-01
In this contribution we present recent progress in the computation of next-to-leading order (NLO) QCD corrections for the production of an electroweak vector boson in association with jets at hadron colliders. We focus on results obtained using the virtual matrix element library BLACKHAT in conjunction with SHERPA, focusing on results relevant to understanding the background to top production.
Electroweak boson production in Pb+Pb
Balestri, T; The ATLAS collaboration
2013-01-01
Lead-lead collisions at the LHC are capable of producing a system of deconfined quarks and gluons at unprecedented energy density and temperature. Partonic-level interactions and energy-loss mechanisms in the medium can be studied with the aid of electroweak bosons which carry important information about the properties of the medium. Electroweak bosons form a class of unique high-$p_{T}$ probes because their decay products do not interact with the strongly-coupled medium, providing a benchmark for a variety of other phenomena measured with strongly interacting particles. The ATLAS experiment measures isolated high-$p_{T}$ photons, W and Z bosons via different decay channels. New analyses of experimental data obtained at the LHC with lead-lead beams at $\\sqrt{s_{NN}}$ = 2.76 TeV. This talk will present a comprehensive study of the scaling properties of electroweak bosons showing linear proportionality of production rates to the nuclear thickness function; rapidity distributions W-decays directly sensitivity to...
HNC variational calculations of boson matter
A simple and reliable numerical technique is given for determining the two-body distribution function which minimizes the HNC energy of boson matter. Numerical results are presented for the neutron matter homework problem and the 4He Lennard-Jones potential. The resulting distribution function is found to have proper asymptotic behaviour and yields reasonable binding energies. (Auth.)
The LIPSS search for light neutral bosons
Andrei Afanasev; Oliver K. Baker; Kevin Beard; George Biallas; James Boyce; Minarni Minarni; Roopchan Ramdon; Michelle D. Shinn; Penny Slocum
2009-07-01
An overview is presented of the LIPSS experimental search for very light neutral bosons using laser light from Jefferson Lab's Free Electron Laser. This facility provides very high power beams of photons over a large optical range, particularly at infrared wavelengths. Data has been collected in several experimental runs during the course of the past three years, most recently in the Fall of 2009.
Normal ordering q-bosons and combinatorics
Combinatorial aspects of normal ordering arbitrary products of q-bosons are discussed. In particular, the number operator and its expectation values in Fock space are shown to be intimately related to the q-deformed version of the generalized Stirling and Bell numbers introduced recently
The decay of a light Higgs boson
Donoghue, J.F. (European Organization for Nuclear Research, Geneva (Switzerland)); Gasser, J.; Leutwyler, H. (Bern Univ. (Switzerland). Inst. fuer Theoretische Physik)
1990-10-22
We discuss the hadronic form factors which are required for the prediction of the decay rate of scalar Higgs bosons, including non-standard generalizations. We calculate the next-to-leading order corrections to the low-energy theorems of chiral symmetry, and use dispersion relations to determine the couplings at higher energy. (orig.).
(spdf) interacting boson model and its application
The group structure and the general form of Hamiltonian of (spdf) interaction boson model are discussed. The energy spectra and the E1,E2 and E3 transition rates of 144Ba and 152Sm are calculated. The results agree with the experimental data quite well
Quantum geometry of bosonic strings - revisited
Botelho, Luiz C.L.; Botelho, Raimundo C.L. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Universidade Federal Rural do Rio de Janeiro, RJ (Brazil). Dept. de Fisica
1999-07-01
We review the original paper by A.M. Polyakov (Quantum Geometry of Bosonic Strings) with corrections and improvements the concepts exposed there and following as closely as possible to the original A.M. Polyakov's paper. (author)
On the trail of the Higgs boson
Peskin, Michael E. [SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-09-11
I review theoretical issues associated with the Higgs boson and the mystery of spontaneous breaking of the electroweak gauge symmetry. In addition, this essay is intended as an introduction to the special issue of Annalen der Physik, “Particle Physics after the Higgs”.
Bosons & More: Celebrating CERN / Part 2
Team, CERN
2013-01-01
The "Bosons & More" event for CERN people this evening celebrated the success of the Open Days, and the exceptional achievements of the Large Hadron Collider (LHC). The British progressive rock band the Alan Parsons Live Project lead the celebrations until late in the night.
Dynamics of the circular bosonic string
After a brief discussion about the Nambu-Goto action, we introduce the concept of transverse velocity and find it for a closed circular bosonic string, then we study and solve the string's equations of movement by using the energy conservation law and finally we sketch its corresponding world sheet. (author).
Le CERN traque le boson de Higgs
2003-01-01
"Avec des 27 kilomètres de circonférence, le LHC, le collisionneur de hadrons, sera le plus grand et le plus puissant accélérateur au monde. Ce géant a été conçu, entre autres, pour détecter le boson de Higgs" (0.5 page)
Accelerating research into the Higgs boson particle
Nikolaidou, Rosy
"The only Standard Model particle yet to be observed, the search for the Higgs Boson - the so-called 'God Particle' - demands advanced facilities and physics expertise. At the Cern laboratory in Switzerland, the ARTEMIS project is well-placed to pursue research in this area" (2 pages)
Single Boson Realizations of the Higgs Algebra
RUANDong; WUChu; SUNHong-Zhou
2003-01-01
We obtained for the Higgs algebra three kinds of single boson realizations such as the unitary Holstein-Primakoff-like realization, the non-unitary Dyson-like realization, and the unitary Villain-like realization. The corre-sponding similarity transformations between the Holstein-Primakoff-like realizations and the Dyson-like realizations are given.
Electroweak Chiral Lagrangian for Neutral Higgs Boson
WANG Shun-Zhi; WANG Qing
2008-01-01
A neutral Higgs boson is added into the traditional electroweak chiral Lagrangian by writing down all possible high dimension operators. The matter part of the Lagrangian is investigated in detail. We find that if Higgs field dependence of Yukawa couplings can be factorized out, there will be no flavour changing neutral couplings; neutral Higgs can induce coupling between light and heavy neutrinos.
Higgs boson masses in supersymmetric models
Imposing supersymmetry on a Higgs potential constrains the parameters that define the potential. In supersymmetric extensions to the stranded model containing only Higgs SU(2)L doublets there exist Higgs boson mass sum rules and bounds on the Higgs masses at tree level. The prescription for renormalizing these sum rules is derived. An explicit calculation is performed in the minimal supersymmetric extension to the standard model (MSSM). In this model at tree level the mass sum rule is MH2 + Mh2 = MA2 + MZ2. The results indicate that large corrections to the sum rules may arise from heavy matter fields, e.g. a heavy top quark. Squarks significantly heavier than their fermionic partners contribute large contributions when mixing occurs in the squark sector. These large corrections result from squark-Higgs couplings that become large in this limit. Contributions to individual Higgs boson masses that are quadratic in the squark masses cancel in the sum rule. Thus the naturalness constraint on Higgs boson masses is hidden in the combination of Higgs boson masses that comprise the sum rule. 39 refs., 13 figs
Electroweak Symmetry Breaking and the Higgs Boson
Pich, Antonio
2015-01-01
The first LHC run has confirmed the Standard Model as the correct theory at the electroweak scale, and the existence of a Higgs-like particle associated with the spontaneous breaking of the electroweak gauge symmetry. These lectures overview the present knowledge on the Higgs boson and discuss alternative scenarios of electroweak symmetry breaking which are already being constrained by the experimental data.
Bosonic physical states in N = 1 supergravity?
Carroll, S M; Ortiz, M E; Page, D N; Carroll, S M; Freedman, D Z; Ortiz, M E; Page, D N
1994-01-01
It is argued that states in N=1 supergravity that solve all of the constraint equations cannot be bosonic in the sense of being independent of the fermionic degrees of freedom. (Based on a talk given by Miguel Ortiz at the 7th Marcel Grossmann Meeting.)
Higgs bosons in the simplest SUSY models
Nowadays, in the MSSM, the moderate values of tan β are almost excluded by the LEP II lower bound on the mass of the lightest Higgs boson. In the next-to-minimal supersymmetric standard model (NMSSM), the theoretical upper bound on it increases and reaches a maximal value in the limit of strong Yukawa coupling, where all solutions to renormalization-group equations are concentrated near the quasifixed point. For a calculation of the Higgs boson spectrum, the perturbation-theory method can be applied. We investigate the particle spectrum within the modified NMSSM, which leads to the self-consistent solution in the limit of strong Yukawa coupling. This model allows one to get mh ∼ 125 GeV at tan β ≥ 1.9. In the model under investigation, the mass of the lightest Higgs boson does not exceed 130.5 ± 3.5 GeV. The upper bound on the mass of the lightest CP-even Higgs boson in more complicated supersymmetric models is also discussed
Grousson, Mathieu
2007-01-01
AT the end of 2007, the most powerful particle accelerator in the world will come into force. Protons will collide at the speed of the light. The great hope of searchers: to find in the remains resulting from these shocks, the famous Higgs boson. (6 pages)
Effective lagrangian from bosonic string field theory
We investigate the low-energy effective action from the string field theoretical view point. The low-energy effective lagrangian for the massless mode of bosonic string is determined to the order of α'. We find a term which can not be determined from the S-matrix approach. (author)
Adler's overrelaxation algorithm for Goldstone bosons
A very simple derivation of a closed-form solution to the stochastic evolution defined by Adler's overrelaxation algorithm is given for free massive and massless scalar fields on a finite lattice with periodic boundary conditions and checkerboard updating. It is argued that the results are directly relevant when critical slowing down reflects the existence of Goldstone bosons in the system
Boson-fermion stars exploring different configurations
Henriques, A B; Henriques, Alfredo B.; Mendes, Luis E.
2003-01-01
We use the flexibility of the concept of a fermion-boson star to explore different configurations, ranging from objects of atomic size and masses of the order $10^{18}$ g, up to objects of galactic masses and gigantic halos around a smaller core, with possible interesting applications to astrophysics and cosmology, particularly in the context of dark matter.
Combinatorial Solutions to Normal Ordering of Bosons
Blasiak, P; Horzela, A; Penson, K A; Solomon, A I
2005-01-01
We present a combinatorial method of constructing solutions to the normal ordering of boson operators. Generalizations of standard combinatorial notions - the Stirling and Bell numbers, Bell polynomials and Dobinski relations - lead to calculational tools which allow to find explicitly normally ordered forms for a large class of operator functions.
Higgs Boson Studies at the Tevatron
Aaltonen, T; Abbott, B; Acharya, B S; Adams, M; Adams, T; Alexeev, G D; Alkhazov, G; Alton, A; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Askew, A; Atkins, S; Auerbach, B; Augsten, K; Aurisano, A; Avila, C; Azfar, F; Badaud, F; Badgett, W; Bae, T; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barbaro-Galtieri, A; Barberis, E; Baringer, P; Barnes, V E; Barnett, B A; Barria, P; Bartlett, J F; Bartos, P; Bassler, U; Bauce, M; Bazterra, V; Bean, A; Bedeschi, F; Begalli, M; Behari, S; Bellantoni, L; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besancon, M; Beuselinck, R; Bhatia, S; Bhatnagar, V; Bhat, P C; Bhatti, A; Bland, K R; Blazey, G; Blessing, S; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Bortoletto, D; Boudreau, J; Boveia, A; Brandt, A; Brandt, O; Brigliadori, L; Brock, R; Bromberg, C; Bross, A; Brown, D; Brucken, E; Budagov, J; Budd, H S; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burkett, K; Busetto, G; Bussey, P; Buszello, C P; Butti, P; Bu, X B; Buzatu, A; Calamba, A; Camacho-Perez, E; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Casey, B C K; Castilla-Valdez, H; Castro, A; Catastini, P; Caughron, S; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chakrabarti, S; Chakraborty, D; Chandra, A; Chan, K M; Chapon, E; Chen, G; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Choi, S; Chokheli, D; Cho, K; Cho, S W; Choudhary, B; Cihangir, S; Ciocci, M A; Claes, D; Clark, A; Clarke, C; Clutter, J; Convery, M E; Conway, J; Cooke, M; Cooper, W E; Corbo, M; Corcoran, M; Cordelli, M; Couderc, F; Cousinou, M C; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; Cutts, D; Das, A; d'Ascenzo, N; Datta, M; Davies, G; de Barbaro, P; de Jong, S J; De La Cruz-Burelo, E; Deliot, F; Demina, R; Demortier, L; Deninno, M; Denisov, D; Denisov, S P; d'Errico, M; Desai, S; Deterre, C; DeVaughan, K; Devoto, F; Di Canto, A; Diehl, H T; Diesburg, M; Ding, P F; Di Ruzza, B; Dittmann, J R; Dominguez, A; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Dubey, A; Dudko, L V; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Ebina, K; Edgar, R; Edmunds, D; Elagin, A; Ellison, J; Elvira, V D; Enari, Y; Erbacher, R; Errede, S; Esham, B; Eusebi, R; Evans, H; Evdokimov, V N; Facini, G; Farrington, S; Faure, A; Feng, L; Ferbel, T; Fernandez Ramos, J P; Fiedler, F; Field, R; Filthaut, F; Fisher, W; Fisk, H E; Flanagan, G; Forrest, R; Fortner, M; Fox, H; Franklin, M; Freeman, J C; Frisch, H; Fuess, S; Funakoshi, Y; Garcia-Bellido, A; Garcia-Gonzalez, J A; Garcia-Guerra, G A; Garfinkel, A F; Garosi, P; Gavrilov, V; Geng, W; Gerber, C E; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Ginther, G; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Goldin, D; Gold, M; Golossanov, A; Golovanov, G; Gomez-Ceballos, G; Gomez, G; Goncharov, M; Gonzalez Lopez, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grannis, P D; Greder, S; Greenlee, H; Grenier, G; Grinstein, S; Gris, Ph; Grivaz, J F; Grohsjean, A; Grosso-Pilcher, C; Group, R C; Grunendahl, S; Grunewald, M W; Guillemin, T; Guimaraes da Costa, J; Gutierrez, G; Gutierrez, P; Hahn, S R; Haley, J; Han, J Y; Han, L; Happacher, F; Hara, K; Harder, K; Harel, A; Hare, M; Harrington-Taber, T; Harr, R F; Hatakeyama, K; Hauptman, J M; Hays, C; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinrich, J; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herndon, M; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hocker, A; Hoeneisen, B; Hogan, J; Hohlfeld, M; Hong, Z; Hopkins, W; Hou, S; Howley, I; Hubacek, Z; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Hynek, V; Iashvili, I; Ilchenko, Y; Illingworth, R; Introzzi, G; Iori, M; Ito, A S; Ivanov, A; Jabeen, S; Jaffre, M; James, E; Jang, D; Jayasinghe, A; Jayatilaka, B; Jeon, E J; Jeong, M S; Jesik, R; Jiang, P; Jindariani, S; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jones, M; Jonsson, P; Joo, K K; Joshi, J; Jung, A W; Junk, T R; Jun, S Y; Juste, A; Kajfasz, E; Kambeitz, M; Kamon, T; Karchin, P E; Karmanov, D; Kasmi, A; Kato, Y; Katsanos, I; Kehoe, R; Kermiche, S; Ketchum, W; Keung, J; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kimura, N; Kim, Y J; Kim, Y K; Kirby, M; Kiselevich, I; Knoepfel, K; Kohli, J M; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kozelov, A V; Kraus, J; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kumar, A; Kupco, A; Kurata, M; Kurca, T; Kuzmin, V A; Laasanen, A T; Lammel, S; Lammers, S; Lancaster, M; Lannon, K; Latino, G; Lebrun, P; Lee, H S; Lee, H S; Lee, J S; Lee, S W; Lee, W M; Lei, X; Lellouch, J; Leone, S; Leo, S; Lewis, J D; Li, D; Li, D; Li, H; Li, L; Lim, J K; Limosani, A; Lincoln, D; Linnemann, J; Lipaev, V V; Lipeles, E; Lipton, R; Li, Q Z; Lister, A; Liu, H; Liu, H; Liu, Q; Liu, T; Liu, Y; Lobodenko, A; Lockwitz, S; Loginov, A; Lokajicek, M; Lopes de Sa, R; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Luna-Garcia, R; Lungu, G; Lyon, A L; Lysak, R; Lys, J; Maciel, A K A; Madar, R; Madrak, R; Maestro, P; Magana-Villalba, R; Malik, S; Malik, S; Malyshev, V L; Manca, G; Manousakis-Katsikakis, A; Mansour, J; Margaroli, F; Marino, P; Martinez, M; Martinez-Ortega, J; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McCarthy, R; McGivern, C L; McNulty, R; Mehta, A; Mehtala, P; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Mesropian, C; Meyer, A; Meyer, J; Miao, T; Miconi, F; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondal, N K; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Mulhearn, M; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nagy, E; Naimuddin, M; Nakano, I; Napier, A; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Nett, J; Neu, C; Neustroev, P; Nguyen, H T; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Nunnemann, T; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Orduna, J; Ortolan, L; Osman, N; Osta, J; Padilla, M; Pagliarone, C; Pal, A; Palencia, E; Palni, P; Papadimitriou, V; Parashar, N; Parihar, V; Parker, W; Park, S K; Partridge, R; Parua, N; Patwa, A; Pauletta, G; Paulini, M; Paus, C; Penning, B; Perfilov, M; Peters, Y; Petridis, K; Petrillo, G; Petroff, P; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pondrom, L; Popov, A V; Poprocki, S; Potamianos, K; Pranko, A; Prewitt, M; Price, D; Prokopenko, N; Prokoshin, F; Ptohos, F; Punzi, G; Qian, J; Quadt, A; Quinn, B; Rangel, M S; Ranjan, N; Ratoff, P N; Razumov, I; Redondo Fernandez, I; Renton, P; Rescigno, M; Rimondi, F; Ripp-Baudot, I; Ristori, L; Rizatdinova, F; Robson, A; Rodriguez, T; Rolli, S; Rominsky, M; 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Wright, T; Wu, X; Wu, Z; Wyatt, T R; Xie, Y; Yamada, R; Yamamoto, K; Yamato, D; Yang, S; Yang, T; Yang, U K; Yang, Y C; Yao, W M; Yasuda, T; Yatsunenko, Y A; Yeh, G P; Ye, W; Ye, Z; Yi, K; Yin, H; Yip, K; Yoh, J; Yorita, K; Yoshida, T; Youn, S W; Yu, G B; Yu, I; Yu, J M; Zanetti, A; Zeng, Y; Zennamo, J; Zhao, T G; Zhou, B; Zhou, C; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L; Zucchelli, S
2013-01-01
We combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90--200 GeV/c^2 produced in the gluon-gluon fusion, WH, ZH, ttbarH, and vector boson fusion processes, and decaying in the H->bbbar, H->W^+W^-, H->ZZ, H->\\tau^+\\tau^-, and H->\\gamma \\gamma\\ modes. The data correspond to integrated luminosities of up to 10 fb^-1 and were collected at the Fermilab Tevatron in ppbar collisions at sqrt(s)=1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV/c^2. The local significance corresponds to 3.1 standard deviations at m_H=125 GeV/c^2, consistent with the mass of the Higgs boson observed at the LHC. Furthermore, we separately combine searches for H->bbbar, H->W^+W^-, H->\\tau^+\\tau^-, and H->\\gamma \\gamma. The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 1...
W and Z boson production at CMS
Romeo Francesco
2013-11-01
Full Text Available We present selected measurements regarding W and Z bosons performed with the CMS detector, based on samples of events collected during 2011 and 2012 LHC physics runs. Measurements include W and Z inclusive cross sections, transverse momentum distribution with Z events, Drell-Yan differential and double-differential cross sections, and lepton charge asymmetry in W events.
Interaction between bosonic dark matter and stars
Brito, Richard; Macedo, Caio F B; Okawa, Hirotada; Palenzuela, Carlos
2015-01-01
We provide a detailed analysis of how bosonic dark matter "condensates" interact with compact stars, extending significantly the results of a recent Letter. We focus on bosonic fields with mass $m_B$, such as axions, axion-like candidates and hidden photons. Self-gravitating bosonic fields generically form "breathing" configurations, where both the spacetime geometry and the field oscillate, and can interact and cluster at the center of stars. We construct stellar configurations formed by a perfect fluid and a bosonic condensate, and which may describe the late stages of dark-matter accretion onto stars, in dark matter-rich environments. These composite stars oscillate at a frequency which is a multiple of $f=2.5\\times 10^{14}\\,\\left(m_{B}c^2/eV\\right)\\,{\\rm Hz}$. Using perturbative analysis and Numerical Relativity techniques, we show that these stars are generically stable, and we provide criteria for instability. Our results also indicate that the growth of the dark matter core is halted close to the Chand...
The best Higgs hunting machine ever built, LEP, started operation in the summer of 1989. Since then the mass region explored in searching for the Standard Model Higgs boson has been extended by more than an order of magnitude. An overview of the searches performed by the four LEP collaborations by the end of 1991 is presented
Trapping fermionic and bosonic helium atoms
Stas, R.J.W.
2005-01-01
This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof