arXiv subjects

C. Krause

Publications and source records attributed to C. Krause.

12 recordsLinked to original sources

arXiv2026

Comment on 'Primary Dimensions'

We show that the concept of primary dimensions, first introduced in [1] as an organizing principle for chiral Lagrangians, is inconsistent. Although this had been pointed out already in [2], the notion of primary dimensions has re-appeared in recent literature. We briefly comment on the proper power counting for such effective field theories, including the electroweak chiral Lagrangian with a light Higgs, which is based on chiral dimensions, equivalent to the counting of loop orders.

hep-ph↗

arXiv2022

Event Generators for High-Energy Physics Experiments

We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these models to be further improved and systematic uncertainties to be reduced, directly contributing to future experimental success. Event generators are part of a much larger ecosystem of computational tools. They typically involve a number of unknown model parameters that must be tuned to experimental data, while maintaining the integrity of the underlying physics models. Making both these data, and the analyses with which they have been obtained accessible to future users is an essential aspect of open science and data preservation. It ensures the consistency of physics models across a variety of experiments.

hep-ph↗

arXiv2021

The InSight HP$^3$ Penetrator (Mole) on Mars: Soil Properties Derived From the Penetration Attempts and Related Activities

The NASA InSight Lander on Mars includes the Heat Flow and Physical Properties Package HP$^3$ to measure the surface heat flow of the planet. The package uses temperature sensors that would have been brought to the target depth of 3--5 m by a small penetrator, nicknamed the mole. The mole requiring friction on its hull to balance remaining recoil from its hammer mechanism did not penetrate to the targeted depth. Instead, by precessing about a point midway along its hull, it carved a 7 cm deep and 5-6 cm wide pit and reached a depth of initially 31 cm. The root cause of the failure - as was determined through an extensive, almost two years long campaign - was a lack of friction in an unexpectedly thick cohesive duricrust. During the campaign -- described in detail in this paper -- the mole penetrated further aided by friction applied using the scoop at the end of the robotic Instrument Deployment Arm and by direct support by the latter. The mole finally reached a depth of 40 cm, bringing the mole body 1--2 cm below the surface. The penetration record of the mole and its thermal sensors were used to measure thermal and mechanical soil parameters such as the thermal conductivity and the penetration resistance of the duricrust and its cohesion. The hammerings of the mole were recorded by the seismometer SEIS and the signals could be used to derive a P-wave velocity and a S-wave velocity and elastic moduli representative of the topmost tens of cm of the regolith. The combined data were used to derive a model of the regolith that has an about 20 cm thick duricrust underneath a 1 cm thick unconsolidated layer of sand mixed with dust and above another 10 cm of unconsolidated sand. Underneath the latter, a layer more resistant to penetration and possibly consisting of debris from a small impact crater is inferred.

astro-ph.IM↗

arXiv2021

The InSight HP$^3$ mole on Mars: Lessons learned from attempts to penetrate to depth in the Martian soil

The NASA InSight mission payload includes the Heat Flow and Physical Properties Package HP$^3$ to measure the surface heat flow. The package was designed to use a small penetrator -- nicknamed the mole -- to implement a string of temperature sensors in the soil to a depth of 5m. The mole itself is equipped with sensors to measure a thermal conductivity as it proceeds to depth. The heat flow would be calculated from the product of the temperature gradient and the thermal conductivity. To avoid the perturbation caused by annual surface temperature variations, the measurements would be taken at a depth between 3 m and 5 m. The mole was designed to penetrate cohesionless soil similar to Quartz sand which was expected to provide a good analogue material for Martian sand. The sand would provide friction to the buried mole hull to balance the remaining recoil of the mole hammer mechanism that drives the mole forward. Unfortunately, the mole did not penetrate more than a mole length of 40 cm. The failure to penetrate deeper was largely due to a few tens of centimeter thick cohesive duricrust that failed to provide the required friction. Although a suppressor mass and spring in the hammer mechanism absorbed much of the recoil, the available mass did not allow a system that would have eliminated the recoil. The mole penetrated to 40 cm depth benefiting from friction provided by springs in the support structure from which it was deployed. It was found in addition that the Martian soil provided unexpected levels of penetration resistance that would have motivated to designing a more powerful mole. It is concluded that more mass would have allowed to design a more robust system with little or no recoil, more energy of the mole hammer mechanism and a more massive support structure.

astro-ph.IM↗

arXiv2020

Higgs-Electroweak Chiral Lagrangian: One-Loop Renormalization Group Equations

Starting from the one-loop divergences we obtained previously, we work out the renormalization of the Higgs-Electroweak Chiral Lagrangian explicitly and in detail. This includes the renormalization of the lowest-order Lagrangian, as well as the decomposition of the remaining divergences into a complete basis of next-to-leading-order counterterms. We provide the list of the corresponding beta functions. We show how our results match the one-loop renormalization of some of the dimension-6 operators in SMEFT. We further point out differences with related work in the literature and discuss them. As an application of the obtained results, we evaluate the divergences of the vacuum expectation value of the Higgs field at one loop and show that they can be appropriately removed by the corresponding renormalization. We also work out the finite renormalization required to keep the no-tadpole condition on the Higgs field at one loop.

hep-ph↗

arXiv2019

First Annealing Studies of Irradiated Silicon Sensors with Modified ATLAS Pixel Implantations

Planar silicon pixel sensors with modified n$^+$-implantation shapes based on the IBL pixel sensor were designed in Dortmund. The sensors with a pixel size of $250\,μ$m $\times$ $50\,μ$m are produced in n$^+$-in-n sensor technology. The charge collection efficiency should improve with electrical field strength maxima created by the different n$^+$-implantation shapes. Therefore, higher particle detection efficiencies at lower bias voltages could be achieved. The modified pixel designs and the IBL standard design are placed on one sensor to test and compare the designs. The sensor can be read out with the FE-I4 readout chip. At the iWoRiD 2018, measurements of sensors irradiated with protons and neutrons respectively at different facilities were presented and showed incongruent results. Unintended annealing during irradiation was considered as an explanation for the observed differences in the hit detection efficiency for two neutron irradiated sensors. This hypothesis will be examined and confirmed in this work, presenting first annealing studies of sensors irradiated with neutrons in Ljubljana.

physics.ins-det↗

arXiv2018

Complete One-Loop Renormalization of the Higgs-Electroweak Chiral Lagrangian

Employing background-field method and super-heat-kernel expansion, we compute the complete one-loop renormalization of the electroweak chiral Lagrangian with a light Higgs boson. Earlier results from purely scalar fluctuations are confirmed as a special case. We also recover the one-loop renormalization of the conventional Standard Model in the appropriate limit.

hep-ph↗

arXiv2016

Reducing current noise in cryogenic experiments by vacuum-insulated cables

We measure the current noise of several cryogenic cables in a pulse tube based dilution refrigerator at frequencies between about 1~mHz and 50~kHz. We show that vibration-induced noise can be efficiently suppressed by using vacuum-insulated cables between room temperature and the 2nd pulse tube stage. A noise peak below 4 fA at the 1.4~Hz operation frequency of the pulse tube, and a white noise density of 0.44 fA/\sqrt{Hz} in the millihertz range are obtained.

physics.ins-det↗

arXiv2016

Standard Model Extended by a Heavy Singlet: Linear vs. Nonlinear EFT

We consider the Standard Model extended by a heavy scalar singlet in different regions of parameter space and construct the appropriate low-energy effective field theories up to first nontrivial order. This top-down exercise in effective field theory is meant primarily to illustrate with a simple example the systematics of the linear and nonlinear electroweak effective Lagrangians and to clarify the relation between them. We discuss power-counting aspects and the transition between both effective theories on the basis of the model, confirming in all cases the rules and procedures derived in previous works from a bottom-up approach.

hep-ph↗

arXiv2016

Fitting Higgs Data with Nonlinear Effective Theory

In a recent paper we showed that the electroweak chiral Lagrangian at leading order is equivalent to the conventional $κ$ formalism used by ATLAS and CMS to test Higgs anomalous couplings. Here we apply this fact to fit the latest Higgs data. The new aspect of our analysis is a systematic interpretation of the fit parameters within an EFT. Concentrating on the processes of Higgs production and decay that have been measured so far, six parameters turn out to be relevant: $c_V$, $c_t$, $c_b$, $c_τ$, $c_{γγ}$, $c_{gg}$. A global Bayesian fit is then performed with the result: $c_{V} = 0.98 \pm 0.09$, $c_{t} = 1.34 \pm 0.19$, $c_{b} = 0.78 \pm 0.18$, $c_τ = 0.92 \pm 0.14$, $c_{γγ} = -0.24 \pm 0.37$, $c_{gg} = -0.30 \pm 0.17$. Additionally, we show how this leading-order parametrization can be generalized to next-to-leading order, thus improving the $κ$ formalism systematically. The differences with a linear EFT analysis including operators of dimension six are also discussed. One of the main conclusions of our analysis is that since the conventional $κ$ formalism can be properly justified within a QFT framework, it should continue to play a central role in analyzing and interpreting Higgs data.

hep-ph↗

arXiv2016

Comment on "Analysis of General Power Counting Rules in Effective Field Theory"

In a recent paper [1] a master formula has been presented for the power counting of a general effective field theory. We first show that this master formula follows immediately from the concept of chiral dimensions (loop counting), together with standard dimensional analysis. Subsequently, [1] has disputed the relevance of chiral counting for chiral Lagrangians, and in particular for the electroweak chiral Lagrangian including a light Higgs boson. As an alternative, a power counting based on `primary dimensions' has been proposed. The difficulties encountered with this scheme led the authors to suggest that even the leading order of the electroweak chiral Lagrangian could not be clearly defined. Here we demonstrate that the concept of primary dimensions is irrelevant for the organization of chiral Lagrangians. We re-emphasize that the correct counting is based on chiral dimensions, or the counting of loop orders, and show how the problems encountered in [1] are resolved.

hep-ph↗

arXiv2015

Note on Anomalous Higgs-Boson Couplings in Effective Field Theory

We propose a parametrization of anomalous Higgs-boson couplings that is both systematic and practical. It is based on the electroweak chiral Lagrangian, including a light Higgs boson, as the effective field theory (EFT) at the electroweak scale $v$. This is the appropriate framework for the case of sizeable deviations in the Higgs couplings of order $10\%$ from the Standard Model, considered to be parametrically larger than new-physics effects in the sector of electroweak gauge interactions. The role of power counting in identifying the relevant parameters is emphasized. The three relevant scales, $v$, the scale of new Higgs dynamics $f$, and the cut-off $Λ=4πf$, admit expansions in $ξ=v^2/f^2$ and $f^2/Λ^2$. The former corresponds to an organization of operators by their canonical dimension, the latter by their loop order or chiral dimension. In full generality the EFT is thus organized as a double expansion. However, as long as $ξ\gg 1/16π^2$ the EFT systematics is closer to the chiral counting. The leading effects in the consistent approximation provided by the EFT, relevant for the presently most important processes of Higgs production and decay, are given by a few (typically six) couplings. These parameters allow us to describe the properties of the Higgs boson in a general and systematic way, and with a precision adequate for the measurements to be performed at the LHC. The framework can be systematically extended to include loop corrections and higher-order terms in the EFT.

hep-ph↗