Related papers: Large bulk matter search for fractional charge par…
We have carried out the largest search for stable particles with fractional electric charge, based on an oil drop method that incorporates a horizontal electric field and upward air flow. No evidence for such particles was found, giving a…
We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied - about 17.4 mg of silicone oil. The search used an improved and highly automated…
We report results from a search for stable particles with charge > $10^{-5}$ e in bulk matter using levitated dielectric microspheres in high vacuum. No evidence for such particles was found in a total sample of 1.4 ng, providing an upper…
We present a new experimental method for searching for free fractional charge in bulk matter; this new method derives from the traditional Millikan liquid drop method, but allows the use of much larger drops, 20 to 100 mm in diameter,…
A search for lightly ionizing particles has been performed with the MACRO detector. This search was sensitive to particles with charges between $\fractional{5}$$e$ and close to the charge of an electron, with $\beta$ between approximately…
A search is presented for free heavy long-lived fractionally charged particles produced in pp collisions at sqrt(s) = 7 TeV. The data sample was recorded by the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0…
A search for stable and long-lived massive particles of electric charge |Q/e|=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at LEP, at centre-of-mass energies from 130 to 209 GeV. These…
In this paper we review the experimental and observational searches for stable, massive, elementary particles other than the electron and proton. The particles may be neutral, may have unit charge or may have fractional charge. They may…
In the Standard Model of particle physics, the quarks and anti-quarks have fractional charge equal to $\pm1/3$ or $\pm2/3$ of the electron's charge. There has been a large number of experiments searching for fractional charge, isolatable,…
The observed Standard Model is consistent with the existence of vector-like species with electric charge a multiple of $e/6$. The discovery of a fractionally charged particle would provide nonperturbative information about Standard Model…
A search is presented for fractionally charged particles with charge below 1$e$, using their small energy loss in the tracking detector as a key variable to observe a signal. The analyzed data set corresponds to an integrated luminosity of…
Particles with electric charge q < 10^(-3)e and masses in the range 1--100 MeV/c^2 are not excluded by present experiments. An experiment uniquely suited to the production and detection of such "millicharged" particles has been carried out…
Approximately 60 years after the Milligan oil drop experiment in 1909, fractionally charged particles (FCPs) were reported to have been discovered in air-shower cores, and the search for FCPs continues to the present day in space,…
Preliminary results on the flux of non strongly-interacting, fractionally charged particles in primary cosmic rays at 400 Km above sea level are given. Cosmic ray data collected by AMS-01 in June 1998 have been analysed on the hypotheses of…
We present the final results of a search for lightly ionizing particles using the entire cosmic ray data set the MACRO detector collected during its 1995-2000 run. Like the original search performed with the data of 1995-96, this search was…
A search for stable and long-lived massive particles of electric charge |Q/e| = 1 or 2/3, pair-produced in e+e- collisions at centre-of-mass energies from 130 to 183 GeV, is reported by the OPAL collaboration at LEP. No evidence for…
Millicharged particles (mCPs) are hypothesized particles possessing an electric charge that is a fraction of the charge of the electron. We report a search for mCPs with charges $\gtrsim 10^{-4}~e$ that improves sensitivity to their…
A search for charged massive (quasi-) stable particles with the D0 detector at the Tevatron collider based on 390 pb^{-1} of data is presented. The search is performed in the frameworks of gauge-mediated supersymmetry breaking and the…
We develop a stochastic model for the charge fluctuations on a microscopic dust particle resting on a surface exposed to plasma. We find in steady state that the fluctuations are normally distributed with a standard deviation that is…
We propose a new experiment at the Large Hadron Collider (LHC) that offers a powerful and model-independent probe for milli-charged particles. This experiment could be sensitive to charges in the range $10^{-3}e - 10^{-1}e$ for masses in…