Introductory remarks about new particles

1977 ◽  
Vol 355 (1683) ◽  
pp. 443-445 ◽  
Keyword(s):  
Particle Physics ◽  
Direct Detection ◽  
Weak Interactions ◽  
Heavy Particle ◽  
New Era ◽  
Elementary Particle Physics ◽  
Electromagnetic Interactions ◽  
Vector Bosons ◽  
First Time ◽  
New Particles

On 11 November 1974, elementary particle physics entered a new era, with simultaneous announcements from the east and west coasts of America that a new heavy particle with astonishingly small decay width had been observed in two quite independent experiments, of different types. Since that time we have all been living through one of the most exciting periods which our field of research has known. The possibility that there might exist new particles of some kind, and possibly of more than one kind, was very much ‘in the air’ during the preceding year or so (Iliopoulos 1974). Attractive theoretical ideas had been put forward some years before (Weinberg 1967) suggesting that a finite gauge theory could be constructed for the weak interactions, which could achieve a unification of the weak and electromagnetic interactions, a goal long sought (Salam & Ward 1964). When a proof of this finiteness (renormalizability) was achieved by t’Hooft (1971 a , b ), physicists had for the first time calculable and meaningful theories unifying the weak and electromagnetic interactions, the analogue for the weak interactions to the photon for the electromagnetic field being very heavy vector bosons, both charged and neutral, whose direct detection still lies quite far in the future. However, not all such theories were necessarily finite. Further conditions had to be met, and a key feature of these is the situation concerning the neutral weak currents.

The weak interactions of the muon - C.E.R.N. work on weak interactions

1965 ◽  
Vol 285 (1401) ◽  
pp. 229-247 ◽  
Keyword(s):  
Elementary Particle ◽  
Particle Physics ◽  
Weak Interactions ◽  
Present Knowledge ◽  
Charged Current ◽  
Elementary Particle Physics ◽  
Hermitian Conjugate

The relation between the muon and the electron is one of the outstanding puzzles in elementary particle physics today. As far as our present knowledge goes, the interactions of the muon are all of the same form and strength as those of the electron. The differences observed between their interaction rates are accounted for entirely as consequences of their difference in mass value, a difference whose origin is not yet known. Otherwise, the only difference established between the muon and the electron is that their weak interactions involve coupling with two distinct neutrinos, V μ and V e respectively. My paper will be concerned with the accuracy and detail with which we know that the weak interactions of the muon and electron are identical in form. All of the evidence available on these interactions is consistent with the hypothesis that these leptons participate in weak interactions only through the charged current vectors, J l and its Hermitian conjugate J ϯ l , given by J lα = ψ̄ l γ α (1 + γ 5 ) Ψ v , and, for simplicity, we shall confine our attention to this hypothesis here.

A Gauge Theory for the Weak and Electromagnetic Interactions

2021 ◽  
pp. 388-404
Author(s):  
J. Iliopoulos ◽  
T.N. Tomaras
Keyword(s):  
Gauge Theory ◽  
Quark Model ◽  
Weak Interactions ◽  
Mass Matrix ◽  
Natural Source ◽  
Apparent Difference ◽  
Electromagnetic Interactions ◽  
Vector Bosons ◽  
Gim Mechanism ◽  
Intermediate Vector

In this chapter we develop the Glashow–Weinberg–Salam theory of electromagnetic and weak interactions based on the gauge group SU(2) × U(1). We show that the apparent difference in strength between the two interactions is due to the Brout–Englert–Higgs phenomenon which results in heavy intermediate vector bosons. The model is presented first for the leptons, and then we argue that the extension to hadrons requires the introduction of a fourth quark. We show that the GIM mechanism guarantees the natural suppression of strangeness changing neutral currents. In the same spirit, the need to introduce a natural source of CP-violation leads to a six quark model with the Cabibbo–Kobayashi–Maskawa mass matrix.

scholarly journals A bottom-up approach to the strong CP problem

2018 ◽  
Vol 33 (14n15) ◽  
pp. 1850088 ◽  
Author(s):  
J. L. Diaz-Cruz ◽  
W. G. Hollik ◽  
U. J. Saldana-Salazar
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Particle Physics ◽  
Weak Interactions ◽  
Theoretical Description ◽  
Strong Interactions ◽  
Top Down ◽  
Bottom Up ◽  
Elementary Particle Physics ◽  
The Standard Model

The strong CP problem is one of many puzzles in the theoretical description of elementary particle physics that still lacks an explanation. While top-down solutions to that problem usually comprise new symmetries or fields or both, we want to present a rather bottom-up perspective. The main problem seems to be how to achieve small CP violation in the strong interactions despite the large CP violation in weak interactions. In this paper, we show that with minimal assumptions on the structure of mass (Yukawa) matrices, they do not contribute to the strong CP problem and thus we can provide a pathway to a solution of the strong CP problem within the structures of the Standard Model and no extension at the electroweak scale is needed. However, to address the flavor puzzle, models based on minimal SU(3) flavor groups leading to the proposed flavor matrices are favored. Though we refrain from an explicit UV completion of the Standard Model, we provide a simple requirement for such models not to show a strong CP problem by construction.

Politični položaj na Slovenskem leta 1919

2020 ◽  
Vol 20 (2020) (2) ◽  
pp. 359-394
Author(s):  
Jurij Perovšek
Keyword(s):  
State Government ◽  
The State ◽  
The Political ◽  
Liberal Party ◽  
New Era ◽  
Party Organisation ◽  
Western Border ◽  
Historical Phenomenon ◽  
First Time ◽  
Similar Development

For Slovenes in the Kingdom of the Serbs, Croats and Slovenes the year 1919 represented the final step to a new political beginning. With the end of the united all-Slovene liberal party organisation and the formation of separate liberal parties, the political party life faced a new era. Similar development was showing also in the Marxist camp. The Catholic camp was united. For the first time, Slovenes from all political camps took part in the state government politics and parliament work. They faced the diminishing of the independence, which was gained in the State of Slovenes, Croats and Serbs, and the mutual fight for its preservation or abolition. This was the beginning of national-political separations in the later Yugoslav state. The year 1919 was characterized also by the establishment of the Slovene university and early occurrences of social discontent. A declaration about the new historical phenomenon – Bolshevism, had to be made. While the region of Prekmurje was integrated to the new state, the questions of the Western border and the situation with Carinthia were not resolved. For the Slovene history, the year 1919 presents a multi-transitional year.

Cinematic Search for Identity in the Shade of Turkey’s 1960 Coup: The Social Realism Debate and The Hope

2017 ◽  
Vol 6 (1) ◽  
pp. 153-168
Author(s):  
Celal Hayir ◽  
Ayman Kole
Keyword(s):  
Party System ◽  
Social Realism ◽  
New Era ◽  
Cultural Life ◽  
The Social ◽  
Turkish Cinema ◽  
To Come ◽  
First Time ◽  
Democratic Constitution ◽  
Realism Debate

When the Turkish army seized power on May 27th, 1960, a new democratic constitution was carried into effect. The positive atmosphere created by the 1961 constitution quickly showed its effects on political balances in the parliament and it became difficult for one single party to come into power, which strengthened the multi-party-system. The freedom initiative created by 1961’s constitution had a direct effect on the rise of public opposition. Filmmakers, who generally steered clear from the discussion of social problems and conflicts until 1960, started to produce movies questioning conflicts in political, social and cultural life for the first time and discussions about the “Social Realism” movement in the ensuing films arose in cinematic circles in Turkey. At the same time, the “regional managers” emerged, and movies in line with demands of this system started to be produced. The Hope (Umut), produced by Yılmaz Güney in 1970, rang in a new era in Turkish cinema, because it differed from other movies previously made in its cinematic language, expression, and use of actors and settings. The aim of this study is to mention the reality discussions in Turkish cinema and outline the political facts which initiated this expression leading up to the film Umut (The Hope, directed by Yılmaz Güney), which has been accepted as the most distinctive social realist movie in Turkey. 

scholarly journals Getting High: High Fidelity Simulation of High Granularity Calorimeters with High Speed

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Erik Buhmann ◽  
Sascha Diefenbacher ◽  
Engin Eren ◽  
Frank Gaede ◽  
Gregor Kasieczka ◽  
...  
Keyword(s):  
Particle Physics ◽  
High Speed ◽  
Deep Neural Networks ◽  
High Fidelity ◽  
High Fidelity Simulation ◽  
Physical Processes ◽  
Electromagnetic Showers ◽  
Information Bottleneck ◽  
First Time ◽  
Processing Network

AbstractAccurate simulation of physical processes is crucial for the success of modern particle physics. However, simulating the development and interaction of particle showers with calorimeter detectors is a time consuming process and drives the computing needs of large experiments at the LHC and future colliders. Recently, generative machine learning models based on deep neural networks have shown promise in speeding up this task by several orders of magnitude. We investigate the use of a new architecture—the Bounded Information Bottleneck Autoencoder—for modelling electromagnetic showers in the central region of the Silicon-Tungsten calorimeter of the proposed International Large Detector. Combined with a novel second post-processing network, this approach achieves an accurate simulation of differential distributions including for the first time the shape of the minimum-ionizing-particle peak compared to a full Geant4 simulation for a high-granularity calorimeter with 27k simulated channels. The results are validated by comparing to established architectures. Our results further strengthen the case of using generative networks for fast simulation and demonstrate that physically relevant differential distributions can be described with high accuracy.

scholarly journals The scalar chemical potential in cosmological collider physics

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Arushi Bodas ◽  
Soubhik Kumar ◽  
Raman Sundrum
Keyword(s):  
Particle Production ◽  
Chemical Potential ◽  
Direct Detection ◽  
Heavy Particle ◽  
Scalar Particle ◽  
Energy Scale ◽  
Fine Tuning ◽  
Tree Level ◽  
Heavy Particles ◽  
Non Gaussian

Abstract Non-analyticity in co-moving momenta within the non-Gaussian bispectrum is a distinctive sign of on-shell particle production during inflation, presenting a unique opportunity for the “direct detection” of particles with masses as large as the inflationary Hubble scale (H). However, the strength of such non-analyticity ordinarily drops exponentially by a Boltzmann-like factor as masses exceed H. In this paper, we study an exception provided by a dimension-5 derivative coupling of the inflaton to heavy-particle currents, applying it specifically to the case of two real scalars. The operator has a “chemical potential” form, which harnesses the large kinetic energy scale of the inflaton, $$ {\overset{\cdot }{\phi}}_0^{1/2}\approx 60H $$ ϕ ⋅ 0 1 / 2 ≈ 60 H , to act as an efficient source of scalar particle production. Derivative couplings of inflaton ensure radiative stability of the slow-roll potential, which in turn maintains (approximate) scale-invariance of the inflationary correlations. We show that a signal not suffering Boltzmann suppression can be obtained in the bispectrum with strength fNL ∼ $$ \mathcal{O} $$ O (0.01–10) for an extended range of scalar masses $$ \lesssim {\overset{\cdot }{\phi}}_0^{1/2} $$ ≲ ϕ ⋅ 0 1 / 2 , potentially as high as 1015 GeV, within the sensitivity of upcoming LSS and more futuristic 21-cm experiments. The mechanism does not invoke any particular fine-tuning of parameters or breakdown of perturbation-theoretic control. The leading contribution appears at tree-level, which makes the calculation analytically tractable and removes the loop-suppression as compared to earlier chemical potential studies of non-zero spins. The steady particle production allows us to infer the effective mass of the heavy particles and the chemical potential from the variation in bispectrum oscillations as a function of co-moving momenta. Our analysis sets the stage for generalization to heavy bosons with non-zero spin.

Sign in / Sign up

Export Citation Format

Share Document