arXiv subjects

Regina Demina

Publications and source records attributed to Regina Demina.

At least 19 recordsLinked to original sources

arXiv2026

Experimental characterization of the hierarchy of quantum correlations in top quark pairs

Recent results from the Large Hadron Collider have demonstrated quantum entanglement of top quark-antiquark pairs using the spin degrees of freedom. Based on the doubly differential measurement of the spin density matrix of the top quark and antiquark performed by the CMS collaboration in the helicity and beam bases, we evaluate a set of quantum observables, including discord, steerability, Bell correlation, and magic. These observables allow for a quantitative characterization of the quantum correlations present in a top quark-antiquark system, thus enabling an interpretation of collider data in terms of quantum states and their properties. Discord is observed to be greater than zero with a significance of more than 5 standard deviations ($\sigma$) in several regions of phase space, some of which correspond to separable quantum states. Evidence for steerability is established for the first time in a high-energy system, with a significance of more than 3$\sigma$. No Bell correlation is observed within the currently probed phase space, in agreement with the theoretical prediction. These results experimentally corroborate the hierarchy of quantum correlations in top quarks with discord being the most basic form of quantum correlation, followed by entanglement, steerability, and Bell correlation. The significance of nonzero magic, which is a complementary observable to the quantum correlation hierarchy, is found to exceed 5$\sigma$ in several regions of phase space.

quant-ph↗

arXiv2025

The Extended Baryonic Tully-Fisher Relation for SDSS MaNGA Galaxies

The baryonic Tully-Fisher relation (BTFR), a relationship between rotational velocity and baryonic mass in spiral galaxies, probes the relative content of baryonic and dark matter in galaxies and thus provides a good test of Lambda CDM. Using H-alpha kinematics to model the rotation curves of spiral galaxies, we construct the BTFR for 5743 SDSS MaNGA DR17 galaxies. To extend the BTFR to higher masses using elliptical galaxies, we estimate their total masses from their stellar velocity dispersions using the virial theorem and define the effective rotational velocity as the velocity a rotation-supported galaxy would exhibit given this mass. The baryonic mass of spiral galaxies is composed of stellar, HI, H2, and He mass, while only the stellar mass is used for the baryonic content of ellipticals. We construct and fit the BTFR for a matched subsample of spiral and elliptical MaNGA and IllustrisTNG 100-1 (TNG100) galaxies, finding BTFR slopes between 3.2 and 4.0. We fit a joint BTFR for the 5743 MaNGA spiral and elliptical galaxies and find a BTFR slope of 3.54 (+0.65/-0.48), which is in good agreement with TNG100 galaxies with baryonic masses greater than 10^9 Msun for which we find a BTFR slope of 3.57 (+0.48/-0.37). Within this mass range, the MaNGA galaxies are consistent with both the Lambda CDM simulation and the prediction from MOND; a sample of lower mass galaxies is necessary to differentiate between the two models.

astro-ph.GA↗

arXiv2025

Beyond the two-point correlation: constraining primordial non-gaussianity with density perturbation moments

Constraining primordial non-Gaussianities (PNGs) in the large-scale cosmic structure (LSS) is an important step in understanding properties of the early universe, specifically in distinguishing between different inflationary models. Measuring PNG relies on evaluating the scale-dependent correlations in the density field. New summary statistics beyond the two- and three-point correlation functions in configuration space and their Fourier-space counterparts, the power- and bi-spectrum may provide increased sensitivity. We introduce a new method for extracting the PNG signal imprinted on the LSS by using the first three Gaussian moments of the normalized correlation in density perturbations, evaluated at varying distance scales. We aim to assess this method's sensitivity to local PNG, parameterized by $f_ {\mathrm{NL}}$. We perform spherical convolutions at a range of scales on dark matter halo simulations to measure the scale-dependent correlations in the density field. From these, we compute the first three moments and compare them to a model expectation vector, parameterized to the second power in $f_{\mathrm{NL}}$. Our method provides about 21% improvement in sensitivity to $f_{\mathrm{NL}}$ with respect to using the two point correlation function alone. Notably, we find that the second moment alone carries nearly as much constraining power as the mean, highlighting the potential of higher-order statistics. Given its simplicity and efficiency, this framework is well-suited for application to current and upcoming large-scale surveys such as DESI.

astro-ph.CO↗

arXiv2025

Quantum Information meets High-Energy Physics: Input to the update of the European Strategy for Particle Physics

Some of the most astonishing and prominent properties of Quantum Mechanics, such as entanglement and Bell nonlocality, have only been studied extensively in dedicated low-energy laboratory setups. The feasibility of these studies in the high-energy regime explored by particle colliders was only recently shown and has gathered the attention of the scientific community. For the range of particles and fundamental interactions involved, particle colliders provide a novel environment where quantum information theory can be probed, with energies exceeding by about 12 orders of magnitude those employed in dedicated laboratory setups. Furthermore, collider detectors have inherent advantages in performing certain quantum information measurements, and allow for the reconstruction of the state of the system under consideration via quantum state tomography. Here, we elaborate on the potential, challenges, and goals of this innovative and rapidly evolving line of research and discuss its expected impact on both quantum information theory and high-energy physics.

hep-ph↗

arXiv2024

Locality in collider tests of Quantum Mechanics with top quark pairs

Tests of quantum properties of fundamental particles in high energy colliders are starting to appear. However, such experiments may suffer from the locality loophole. We argue for criteria that take into account the space-like separation between measurements for the case of spin correlations in top quark pairs produced at the LHC. We derive bounds considering three different definitions of what constitutes the quantum measurement - the decay of top quarks, the decay of W bosons, and the stable decay products contacting a macroscopic device.

hep-ph↗

arXiv2024

A Full Accounting of the Visible Mass in SDSS MaNGA Disk Galaxies

We present a study of the ratio of visible mass to total mass in spiral galaxies to better understand the relative amount of dark matter present in galaxies of different masses and evolutionary stages. Using the velocities of the H-alpha emission line measured in spectroscopic observations from the Sloan Digital Sky Survey (SDSS) MaNGA Data Release 17 (DR17), we evaluate the rotational velocity of over 5500 disk galaxies at their 90% elliptical Petrosian radii, R90. We compare this to the velocity expected from the total visible mass, which we compute from the stellar, HI, molecular hydrogen, and heavy metals and dust masses. Molecular hydrogen mass measurements are available for only a small subset of galaxies observed in SDSS MaNGA DR17, so we derive a parameterization of the molecular hydrogen mass as a function of absolute magnitude in the r band using galaxies observed as part of SDSS DR7. With these parameterizations, we calculate the fraction of visible mass within R90 that corresponds to the observed velocity. Based on statistically analyzing the likelihood of this fraction, we conclude that the null hypothesis (no dark matter) cannot be excluded at a confidence level better than 95% within the visible extent of the disk galaxies. We also find that when all mass components are included, the ratio of visible-to-total mass within the visible extent of star-forming disk galaxies increases with galaxy luminosity.

astro-ph.GA↗

arXiv2022

Report of the Topical Group on Top quark physics and heavy flavor production for Snowmass 2021

This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios.

hep-ph↗

arXiv2022

The MegaMapper: A Stage-5 Spectroscopic Instrument Concept for the Study of Inflation and Dark Energy

In this white paper, we present the MegaMapper concept. The MegaMapper is a proposed ground-based experiment to measure Inflation parameters and Dark Energy from galaxy redshifts at $2<z<5$. In order to achieve path-breaking results with a mid-scale investment, the MegaMapper combines existing technologies for critical path elements and pushes innovative development in other design areas. To this aim, we envision a 6.5-m Magellan-like telescope, with a newly designed wide field, coupled with DESI spectrographs, and small-pitch robots to achieve multiplexing of at least 26,000. This will match the expected achievable target density in the redshift range of interest and provide a 10x capability over the existing state-of the art, without a 10x increase in project budget.

astro-ph.IM↗

arXiv2021

Dependence of the ratio of total to visible mass on observable properties of SDSS MaNGA galaxies

Using spectroscopic observations from the SDSS MaNGA DR15, we study the relationships between the ratio of total to visible mass and various parameters characterizing the evolution and environment of the galaxies in this survey. Measuring the rotation curve with the relative velocities of the H-alpha emission line across the galaxy's surface, we estimate each galaxy's total mass. We develop a statistical model to describe the observed distribution in the ratio of total to visible mass, from which we extract a galaxy's most probable value for this mass ratio. We present the relationships between the ratio of total to visible mass and several characteristics describing galactic evolution, such as luminosity, gas-phase metallicity, distance to the nearest neighbor, and position on the color-magnitude diagram. We find that faint galaxies with low metallicities, typically in the blue cloud, have the highest ratios of total to visible mass. Those galaxies that exhibit the second highest ratios of total to visible mass are the brightest with high metallicities, typically members of the red sequence or green valley. AGN activity is likely both the quenching mechanism and the feedback that drives the mass ratio higher in these massive galaxies. Finally, we introduce a parametrization that predicts a galaxy's ratio of total to visible mass based on its photometry and luminosity.

astro-ph.GA↗

arXiv2021

ConKer: evaluating isotropic correlations of arbitrary order

High order correlations in the cosmic matter density have become increasingly valuable in cosmological analyses. However, computing such correlation functions is computationally expensive. We aim to circumvent these challenges by designing a new method of estimating correlation functions. This is realized in ConKer, an algorithm that performs FFT convolutions of matter distributions with spherical kernels. ConKer is applied to the CMASS sample of the SDSS DR12 galaxy survey and used to compute the isotropic correlation up to correlation order n = 5. We also compare the n = 2 and n = 3 cases to traditional algorithms to verify the accuracy of the new method. We perform a timing study of the algorithm and find that two of the three components of the algorithm are independent of the catalog size, N, while one component is O(N), which starts dominating for catalogs larger than 10M objects. For n < 5 the dominant calculation is O(N^(4/3logN)), where N is the number of the grid cells. For higher n, the execution time is expected to be dominated by a component with time complexity O(N^((n+2)/3)). We find ConKer to be a fast and accurate method of probing high order correlations in the cosmic matter density.

astro-ph.CO↗

arXiv2020

The influence of the void environment on the ratio of dark matter halo mass to stellar mass in SDSS MaNGA galaxies

We study how the void environment affects the formation and evolution of galaxies in the universe by comparing the ratio of dark matter halo mass to stellar mass of galaxies in voids with galaxies in denser regions. Using spectroscopic observations from the SDSS MaNGA DR15, we estimate the dark matter halo mass of 642 void galaxies and 938 galaxies in denser regions. We use the relative velocities of the H-alpha emission line across the galaxy's surface to measure the rotation curve of each galaxy because the kinematics of the interstellar medium is smoother than the stellar kinematics. We find that neither the stellar-to-halo-mass relation nor the relationship between the gas-phase metallicity and the ratio of dark matter halo mass to stellar mass is affected by the void environment. We also observe no difference in the distribution of the ratio of dark matter halo mass to stellar mass between void galaxies and galaxies in denser regions, implying that the shape of the dark matter halo profile is independent of a galaxy's environment.

astro-ph.GA↗

arXiv2019

Fast Mock Catalog Generation for Large Scale Structure Modeling

To understand the universe and to interpret the cosmological parameters governing its evolution it is necessary to contrast the data from galaxy surveys with simulation. Typically it entails using computationally expensive N -body simulations. Computational overhead makes it difficult to test the dependence of galaxy large scale structure on multiple cosmological parameters. In this work, we suggest a parametric model to simulate large scale structure. The new method provides a fast way to generate mock catalogs for testing multiple cosmological parameters as well as providing a test bench for code development.

astro-ph.CO↗

arXiv2017

A Computationally Efficient Approach for Calculating Galaxy Two-Point Correlations

We developed a modification to the calculation of the two-point correlation function commonly used in the analysis of large scale structure in cosmology. An estimator of the two-point correlation function is constructed by contrasting the observed distribution of galaxies with that of a uniformly populated random catalog. Using the assumption that the distribution of random galaxies in redshift is independent of angular position allows us to replace pairwise combinatorics with fast integration over probability maps. The new method significantly reduces the computation time while simultaneously increasing the precision of the calculation. It also allows to introduce cosmological parameters only at the last and least computationally expensive stage, which is helpful when exploring various choices for these parameters.

astro-ph.CO↗

arXiv2015

Reconstructing top quark-antiquark events with one lost jet

We present a technique for reconstructing the kinematics of pair-produced top quarks that decay to a charged lepton, a neutrino and four final state quarks in the subset of events where only three jets are reconstructed. We present a figure of merit that allows for a fair comparison of reconstruction algorithms without requiring their calibration. The new reconstruction of events with only three jets is fully competitive with the full reconstruction typically used for four jet events.

hep-ex↗

arXiv2013

Analytic solutions for neutrino momenta in decay of top quarks

We employ a geometric approach to analytically solving equations of constraint on the decay of top quarks involving leptons. The neutrino momentum is found as a function of the 4-vectors of the associated bottom quark and charged lepton, the masses of the top quark and W boson, and a single parameter, which constrains it to an ellipse. We show how the measured imbalance of momenta in the event reduces the solutions for neutrino momenta to a discrete set, in the cases of one or two top quarks decaying to leptons. The algorithms can be implemented concisely with common linear algebra routines.

hep-ph↗

arXiv2010

Czochralski Silicon as a Detector Material for S-LHC Tracker Volumes

With an expected ten-fold increase in luminosity in S-LHC, the radiation environment in the tracker volumes will be considerably harsher for silicon-based detectors than the already harsh LHC environment. Since 2006, a group of CMS institutes, using a modified CMS DAQ system, has been exploring the use of Magnetic Czochralski silicon as a detector element for the strip tracker layers in S-LHC experiments. Both p+/n-/n+ and n+/p-/p+ sensors have been characterized, irradiated with proton and neutron sources, assembled into modules, and tested in a CERN beamline. There have been three beam studies to date and results from these suggest that both p+/n-/n+ and n+/p-/p+ Magnetic Czochralski silicon are sufficiently radiation hard for the $R>25$ cm regions of S-LHC tracker volumes. The group has also explored the use of forward biasing for heavily irradiated detectors, and although this mode requires sensor temperatures less than -50\,$^\circ$C, the charge collection efficiency appears to be promising.

physics.ins-det↗

arXiv2004

Supersymmetry searches at the Tevatron

CDF and D0 collaborations analyzed up to 200 pb-1 of the delivered data in search for different supersymmetry signatures, so far with negative results. We present results on searches for chargino and neutralino associated production, squarks and gluinos, sbottom quarks, gauge mediated SUSY breaking and long lived heavy particles.

hep-ex↗

arXiv2000

Low-Scale and Gauge-Mediated Supersymmetry Breaking at the Fermilab Tevatron Run II

The prospects for discovering and studying signals of low-scale supersymmetry breaking models at the Tevatron Run II and beyond are explored. These models include gauge-mediated supersymmetry breaking as the most compelling and concrete realization, but more generally are distinguished by the presence of a nearly massless Goldstino as the lightest supersymmetric particle. The next-lightest supersymmetric particle(s) (NLSP) decays to its partner and the Goldstino. Depending on the supersymmetry breaking scale, these decays can occur promptly or on a scale comparable to or larger than the size of a detector. A systematic analysis based on a classification in terms of the identity of the NLSP and its decay length is presented. The various scenarios are discussed in terms of signatures and possible event selection criteria. The Run II and beyond discovery and exclusion reaches, including the effects of background, are detailed for the most compelling cases. In addition to standard event selection criteria based on missing energy and photons, leptons, jets, taus, tagged b-jets, or reconstructed Z-bosons, more exotic signals of metastable NLSPs such as displaced photons, large negative impact parameter tracks, kink tracks, both opposite and same-sign highly ionizing tracks, time of flight measurements, charge-changing tracks, charge-exchange tracks, and same-sign di-top events are investigated. The interesting possibility of observing a Higgs boson signal in events that are efficiently "tagged" by the unique signatures of low-scale supersymmetry breaking is also considered.

hep-ph↗