135 research outputs found
Solving String Field Equations: New Uses for Old Tools
It is argued that the (NS-sector) superstring field equations are integrable,
i.e. their solutions are obtainable from linear equations. We adapt the
25-year-old solution-generating "dressing" method and reduce the construction
of nonperturbative superstring configurations to a specific cohomology problem.
The application to vacuum superstring field theory is outlined.Comment: Talk presented by O.L. at the 35th International Symposium Ahrenshoop
on the Theory of Elementary Particles, Berlin, Germany, 26-30 Aug 2002; v2:
minor corrections, textheight adjuste
FASER: ForwArd Search ExpeRiment at the LHC
New physics has traditionally been expected in the high- region at
high-energy collider experiments. If new particles are light and
weakly-coupled, however, this focus may be completely misguided: light
particles are typically highly concentrated within a few mrad of the beam line,
allowing sensitive searches with small detectors, and even extremely
weakly-coupled particles may be produced in large numbers there. We propose a
new experiment, ForwArd Search ExpeRiment, or FASER, which would be placed
downstream of the ATLAS or CMS interaction point (IP) in the very forward
region and operated concurrently there. Two representative on-axis locations
are studied: a far location, from the IP and just off the beam
tunnel, and a near location, just from the IP and right behind
the TAN neutral particle absorber. For each location, we examine leading
neutrino- and beam-induced backgrounds. As a concrete example of light,
weakly-coupled particles, we consider dark photons produced through light meson
decay and proton bremsstrahlung. We find that even a relatively small and
inexpensive cylindrical detector, with a radius of and
length of , depending on the location, can discover dark photons
in a large and unprobed region of parameter space with dark photon mass and kinetic mixing parameter . FASER will clearly also be sensitive to many other forms of
new physics. We conclude with a discussion of topics for further study that
will be essential for understanding FASER's feasibility, optimizing its design,
and realizing its discovery potential.Comment: 35 Pages, 12 figures. Version 2, references added, minor change
Looking forward to test the KOTO anomaly with FASER
The search for light and long-lived particles at the LHC will be intensified
in the upcoming years with a prominent role of the new FASER experiment. In
this study, we discuss how FASER could independently probe such scenarios
relevant for new physics searches at kaon factories. We put an emphasis on the
proposed explanations for the recently observed three anomalous events in the
KOTO experiment. The baseline of FASER precisely corresponds to the proposed
lifetime solution to the anomaly that avoids the NA62 bounds on charged kaons.
As a result, the experiment can start constraining relevant models within the
first few weeks of its operation. In some cases, it can confirm a possible
discovery with up to 10000 spectacular high-energy events in FASER during LHC
Run 3. Further complementarities between FASER and kaon factories, which employ
FASER capability to study di-photon signatures, are illustrated for the model
with axion-like particles dominantly coupled to gauge bosons.Comment: Version published in PR
Investigating the fluxes and physics potential of LHC neutrino experiments
The initiation of a novel neutrino physics program at the Large Hadron
Collider (LHC) and the purpose-built Forward Physics Facility (FPF) proposal
have motivated studies exploring the discovery potential of these searches.
This requires resolving degeneracies between new predictions and uncertainties
in modeling neutrino production in the forward kinematic region. The present
work investigates a broad selection of existing predictions for the parent
hadron spectra at FASER and the FPF to parameterize expected correlations
in the neutrino spectra produced in their decays and to determine the highest
achievable precision for their observation based on Fisher information. This
allows for setting constraints on various physics processes within and beyond
the Standard Model, including neutrino non-standard interactions. We also
illustrate how combining multiple neutrino observables could lead to
experimental confirmation of the enhanced-strangeness scenario proposed to
resolve the cosmic-ray muon puzzle already during the ongoing LHC Run 3.Comment: 21 pages, 5 figure
Thermodynamical Properties of a Rotating Ideal Bose Gas
In a recent experiment, a Bose-Einstein condensate was trapped in an
anharmonic potential which is well approximated by a harmonic and a quartic
part. The condensate was set into such a fast rotation that the centrifugal
force in the corotating frame overcompensates the harmonic part in the plane
perpendicular to the rotation axis. Thus, the resulting trap potential became
Mexican-hat shaped. We present an analysis for an ideal Bose gas which is
confined in such an anharmonic rotating trap within a semiclassical
approximation where we calculate the critical temperature, the condensate
fraction, and the heat capacity. In particular, we examine in detail how these
thermodynamical quantities depend on the rotation frequency.Comment: Author Information under
http://www.theo-phys.uni-essen.de/tp/ags/pelster_dir
Extending the reach of FASER, MATHUSLA, and SHiP towards smaller lifetimes using secondary particle production
Many existing or proposed intensity-frontier search experiments look for
decay signatures of light long-lived particles (LLPs), highly displaced from
the interaction point, in a distant detector that is well-shielded from SM
background. This approach is, however, limited to new particles with decay
lengths similar to or larger than the baseline of those experiments. In this
study, we discuss how this basic constraint can be overcome in BSM models that
go beyond the simplest scenarios. If more than one light new particle is
present in the model, an additional secondary production of LLPs may take place
right in front of the detector, opening this way a new lifetime regime to be
probed. We illustrate the prospects of such searches in the future experiments
FASER, MATHUSLA and SHiP, for representative models, emphasizing possible
connections to dark matter or an anomalous magnetic moment of muon. We also
analyze additional advantages from employing dedicated neutrino detectors
placed in front of the main decay volume.Comment: 33 pages, 13 figures, 1 table, typos corrected in appendices, no
results affecte
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