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Y. K. Semertzidis

Publications and source records attributed to Y. K. Semertzidis.

At least 37 records · Page 2Linked to original sources

The fast non-ferric kicker system for the Muon $g-2$ Experiment at Fermilab

We describe the installation, commissioning, and characterization of the new injection kicker system in the Muon $g-2$ Experiment (E989) at Fermilab, which makes a precision measurement of the muon magnetic anomaly. Three Blumlein pulsers drive each of the 1.27-m-long non-ferric kicker magnets, which reside in a storage ring vacuum (SRV) that is subjected to a 1.45 T magnetic field. The new system has been redesigned relative to Muon $g-2$'s predecessor experiment, and we present those details in this manuscript.

physics.ins-det↗

Improved axion haloscope search analysis

One of the most significant and practical figures of merit in axion haloscope searches is the scanning rate, because of the unknown axion mass. Under the best experimental parameters, the only way to improve the figure of merit is to increase the experimentally designed signal to noise ratio in the axion haloscope search analysis procedure. In this paper, we report an improved axion haloscope search analysis using the data taken by the CAPP-8TB haloscope. By correcting for the background biased by the background parametrizations in the presence of axion signals, we realized a signal to noise ratio efficiency of about 100\%. Given the axion haloscope search analyses to date, the scanning rate can be improved by 21\%, with about a 10\% improvement in the signal to noise ratio. This improvement is another low cost innovation in axion haloscope searches, where all the experimental parameters are currently at their best.

astro-ph.CO↗

Noise temperature measurements for axion haloscope experiments at IBS/CAPP

The axion was first introduced as a consequence of the Peccei-Quinn mechanism to solve the CP problem in strong interactions of particle physics and is a well motivated cold dark matter candidate. This particle is expected to interact extremely weakly with matter and its mass is expected to lie in $μ$eV range with the corresponding frequency roughly in GHz range. In 1983 P. Sikivie proposed a detection scheme, so called axion haloscope, where axions resonantly convert to photons in a tunable microwave cavity permeated by a strong magnetic field. A major source of the experimental noise is attributed to added noise by RF amplifiers, and thus precise understandings of amplifiers' noise is of importance. We present the measurements of noise temperatures of various low noise amplifiers broadly used for axion dark matter searches.

physics.ins-det↗

CAPP-8TB: Axion Dark Matter Search Experiment around 6.7 $μ$eV

CAPP-8TB is an axion dark matter search experiment dedicated to an axion mass search near 6.7 $μ$eV. The experiment uses a microwave resonant cavity under a strong magnetic field of 8 T produced by a superconducting solenoid magnet in a dilution refrigerator. We describe the experimental configuration used to search for a mass range of 6.62 to 6.82 $μ$eV in the first phase of the experiment. We also discuss the next phase of the experiment and its prospects.

physics.ins-det↗

Response-suggestion to The XENON1T excess: an overlooked dark matter signature?

The main alternatives of the recent XENON1T observation are solar axions, neutrino magnetic moment and tritium. In this short note we suggest to crosscheck whether the observation is related or not to dark matter (DM) streams, by searching for planetary dependence of the observed excess. If such a correlation is derived, this hint (<3.5sigma) can become the overlooked direct DM discovery. To do this it is necessary to analyze the time distribution of all the XENON1T data, and in particular the electronic events with their time stamp and energy. Notably, the velocities of the dark sector allow for planetary focusing effects towards the earth either by a single celestial body or combined by the whole solar system. Surprisingly, as yet this possibility has not been applied in the field of direct dark matter search, even though DM velocities fit-in well planetary gravitational lensing effects. The widely used signature of a direct dark matter search needs to be redefined, while, with luck, such an analysis might confirm or exclude the solar origin of the observed excess. Therefore, we suggest that XENON1T and DAMA release the data.

hep-ph↗

Stratospheric temperature anomalies as imprints from the dark Universe

The manifestation of the dark Universe begun with unexpected large scale astronomical observations. Here we are investigating the origin of small scale anomalies, like that of the annually observed temperature anomalies in the stratosphere. Unexpectedly, we observe a planetary relationship of the daily stratospheric temperature distribution. Its spectral shape does not match concurrent solar activity, or solar EUV emission, whose impact on the atmosphere is unequivocal. This behavior points at an additional energy source of exosolar origin. A viable concept behind such observations is based on possible gravitational focusing by the solar system towards the Earth of low speed invisible matter. We denote generic constituents from the dark Universe as invisible matter, in order to distinguish them from ordinary dark matter candidates like axions or WIMPs, which cannot have any noticeable impact on the stratosphere. The observed peaking planetary relations exclude on their own any conventional explanation. Only a somehow strongly interacting invisible streaming matter with the little screened upper stratosphere (noverhead about 1 gr/cm 2) can be behind the occasionally observed temperature increases. We also estimate an associated energy deposition O(W/m 2), which is variable over the 11 years solar cycle. For the widely assumed picture of a quasi not interacting dark Universe, this new exosolar energy is enormous. Since the atmosphere is uninterruptedly monitored since decades, it can serve also parasitically as a novel low threshold detector for the dark Universe, with built-in spatiotemporal resolution and the solar system acting temporally as signal amplifier. In future, analyzing more observations, for example, from the anomalous ionosphere, or, the transient sudden stratospheric warmings, the nature of the assumed invisible streams could be deciphered.

astro-ph.EP↗

Axion Dark Matter Search around 6.7 $μ$eV

An axion dark matter search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling $g_{aγγ}$ down to the QCD axion band over the axion mass range between 6.62 and 6.82 $μ$eV at a 90\% confidence level, which is the most sensitive result in the mass range to date.

hep-ex↗

First Results on the Search for Chameleons with the KWISP Detector at CAST

We report on a first measurement with a sensitive opto-mechanical force sensor designed for the direct detection of coupling of real chameleons to matter. These dark energy candidates could be produced in the Sun and stream unimpeded to Earth. The KWISP detector installed on the CAST axion search experiment at CERN looks for tiny displacements of a thin membrane caused by the mechanical effect of solar chameleons. The displacements are detected by a Michelson interferometer with a homodyne readout scheme. The sensor benefits from the focusing action of the ABRIXAS X-ray telescope installed at CAST, which increases the chameleon flux on the membrane. A mechanical chopper placed between the telescope output and the detector modulates the incoming chameleon stream. We present the results of the solar chameleon measurements taken at CAST in July 2017, setting an upper bound on the force acting on the membrane of $80$~pN at 95\% confidence level. The detector is sensitive for direct coupling to matter $10^4 \leqβ_m \leq 10^8$, where the coupling to photons is locally bound to $β_γ\leq 10^{11}$.

hep-ex↗

A New Approach for Measuring the Muon Anomalous Magnetic Moment and Electric Dipole Moment

This paper introduces a new approach to measure the muon magnetic moment anomaly $a_μ = (g-2)/2$, and the muon electric dipole moment (EDM) $d_μ$ at the J-PARC muon facility. The goal of our experiment is to measure $a_μ$ and $d_μ$ using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon $g-2$ experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1,000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for $a_μ$ is statistical uncertainty of 450 part per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of $1.5\times 10^{-21}~e\cdot\mbox{cm}$.

physics.ins-det↗

Improved Search for Solar Chameleons with a GridPix Detector at CAST

We report on a new search for solar chameleons with the CERN Axion Solar Telescope (CAST). A GridPix detector was used to search for soft X-ray photons in the energy range from 200 eV to 10 keV from converted solar chameleons. No signiffcant excess over the expected background has been observed in the data taken in 2014 and 2015. We set an improved limit on the chameleon photon coupling, $β_γ< 5.7\times10^{10}$ for $1<β_\mathrm{m}<10^6$ at 95% C.L. improving our previous results by a factor two and for the first time reaching sensitivity below the solar luminosity bound for tachocline magnetic fields up to $12.5\,\mathrm{T}$.

hep-ex↗

aKWISP: investigating short-distance interactions at sub-micron scales

The sub-micron range in the field of short distance interactions has yet to be opened to experimental investigation, and may well hold the key to understanding al least part of the dark matter puzzle. The aKWISP (advanced-KWISP) project introduces the novel Double Membrane Interaction Monitor (DMIM), a combined source-sensing device where interaction distances can be as short as 100 nm or even 10 nm, much below the 1-10 micron distance which is the lower limit encountered by current experimental efforts. aKWISP builds on the technology and the results obtained with the KWISP opto-mechanical force sensor now searching at CAST for the direct coupling to matter of solar chameleons. It will reach the ultimate quantum-limited sensitivity by exploiting an array of technologies, including operation at milli-Kelvin temperatures. Recent suggestions point at short-distance interactions studies as intriguing possibilities for the detection of axions and of new physical phenomena.

physics.ins-det↗

New CAST Limit on the Axion-Photon Interaction

During 2003--2015, the CERN Axion Solar Telescope (CAST) has searched for $a\toγ$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. In its final phase of solar axion searches (2013--2015), CAST has returned to evacuated magnet pipes, which is optimal for small axion masses. The absence of a significant signal above background provides a world leading limit of $g_{aγ} < 0.66 \times 10^{-10} {\rm GeV}^{-1}$ (95% C.L.) on the axion-photon coupling strength for $m_a \lesssim 0.02$ eV. Compared with the first vacuum phase (2003--2004), the sensitivity was vastly increased with low-background x-ray detectors and a new x-ray telescope. These innovations also serve as pathfinders for a possible next-generation axion helioscope.

hep-ex↗

The connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring

In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that the x and y chromaticities vanish and the maximizing of the lifetime of in-plane polarization (IPP) for a 0.97-GeV/c deuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbon-target polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.

physics.acc-ph↗

First axion dark matter search with toroidal geometry

We firstly report an axion haloscope search with toroidal geometry. In this pioneering search, we exclude the axion-photon coupling $g_{aγγ}$ down to about $5\times10^{-8}$ GeV$^{-1}$ over the axion mass range from 24.7 to 29.1 $μ$eV at a 95\% confidence level. The prospects for axion dark matter searches with larger scale toroidal geometry are also considered.

hep-ex↗

Search for axions in streaming dark matter

A new search strategy for the detection of the elusive dark matter (DM) axion is proposed. The idea is based on streaming DM axions, whose flux might get temporally enormously enhanced due to gravitational lensing. This can happen if the Sun or some planet (including the Moon) is found along the direction of a DM stream propagating towards the Earth location. The experimental requirements to the axion haloscope are a wide-band performance combined with a fast axion rest mass scanning mode, which are feasible. Once both conditions have been implemented in a haloscope, the axion search can continue parasitically almost as before. Interestingly, some new DM axion detectors are operating wide-band by default. In order not to miss the actually unpredictable timing of a potential short duration signal, a network of co-ordinated axion antennae is required, preferentially distributed world-wide. The reasoning presented here for the axions applies to some degree also to any other DM candidates like the WIMPs.

physics.ins-det↗

Electric and magnetic energy at axion haloscopes

We review a recent letter published in Phys. Rev. Lett. $\textbf{116}$, 161804 (2016) of which the main argument is that the mode dependent magnetic form factors at axion haloscopes depend on the position of the cavity inside the solenoid while the corresponding electric form factors do not. We, however, find no such dependence, which is also equivalent to the statement that the electric and corresponding magnetic energy stored in the cavity modes are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend the statement to the cases satisfying $\vec{\nabla}\times\vec{B}_{\rm external}=0$, where $\vec{B}_{\rm external}$ is a static magnetic field provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and toroidal, satisfy $\vec{\nabla}\times\vec{B}_{\rm external}=0$, thus the electric and corresponding magnetic energy stored in the cavity modes are always the same in both cases. The energy, however, is independent of the position of the cavity in axion haloscopes with a solenoid, but depends on those with a toroidal magnet.

hep-ph↗

Comment on "Axion Dark Matter Coupling to Resonant Photons via Magnetic Field"

A recent Letter, Phys. Rev. Lett. 116, 161804 (2016), claims that for typical dark matter axion search experiments using cylindrical haloscopes, the power gain depends on the relative position of a cavity with respect to the center of a solenoidal magnetic field due to different electric and magnetic couplings. We review this Letter and find a misinterpretation of the coordinate system. We correct this and see no dependence of the coupling strength on the cavity location and the electric and magnetic energies stored in a cavity mode are equal.

hep-ex↗

Recent Progress with the KWISP Force Sensor

The KWISP opto-mechanical force sensor has been built and calibrated in the INFN Trieste optics laboratory and is now under off-beam commissioning at CAST. It is designed to detect the pressure exerted by a flux of solar Chameleons on a thin (100 nm) Si$_3$N$_4$ micromembrane thanks to their direct coupling to matter. A thermally-limited force sensitivity of $1.5 \cdot 10^{-14}~\mbox{N}/\sqrt{\mbox{Hz}}$, corresponding to $7.5 \cdot 10^{-16}~\mbox{m}/\sqrt{\mbox{Hz}}$ in terms of displacement, has been obtained. An originally developed prototype chameleon chopper has been used in combination with the KWISP force sensor to conduct preliminary searches for solar chamaleons.

physics.ins-det↗