Nuclear Theory·nucl-th

Wednesday·October 4, 2023

14 papers—6 primary·8 cross-listed

07
[Submitted on 2 Oct 2023] (cross-list from hep-ph)
Partial Rate Matrix for Dark Matter Scattering
Benjamin Lillard🇺🇸
I present a highly efficient integration method for scattering calculations, and a ``partial rate matrix'' that encodes the scattering rate as a function of the $S O (3)$ orientation of the detector. This replaces the original multidimensional rate integral with a simple exercise in vector multiplication, speeding up the rate calculation by a factor of around $1 0^{8}$ . I include a scheme to fully factorize the dark matter particle model, its astrophysical velocity distribution, and the properties of the target material from each other, enabling efficient calculation of the partial rate matrix even in studies comparing large sets of these input functions. This is now the only sensible way to evaluate the dark matter scattering rate in anisotropic detector materials. It is straightforward to generalize this method to other difficult but linear problems.
Comments:
6 pages, 1 figure, 2 appendices. Updated to match journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2310.01480 [pdf]
PRL(2025)·11 citations
08
[Submitted on 2 Oct 2023] (cross-list from hep-ph)
Wavelet-Harmonic Integration Methods
Benjamin Lillard🇺🇸
A new integration method drastically improves the efficiency of the dark matter direct detection calculation. In this work I introduce a complete, orthogonal basis of spherical wavelet-harmonic functions, designed for the new vector space integration method. This factorizes the numeric calculation into a ``vector'' that depends only on the astrophysical velocity distribution; a second vector, depending only on the detector form factor; and a scattering matrix defined on the basis functions, which depends on the details of the dark matter (DM) particle model (e.g.~its mass). For common spin-independent DM--Standard Model interactions, this scattering matrix can be evaluated analytically in the wavelet-harmonic basis. This factorization is particularly helpful for the more complicated analyses that have become necessary in recent years, especially those involving anisotropic detector materials or more realistic models of the local DM velocity distribution. With the new method, analyses studying large numbers of detector orientations and DM particle models can be performed more than 10~million times faster. This paper derives several analytic results for the spherical wavelets, including an extrapolation in the space of wavelet coefficients, and a generalization of the vector space method to a much broader class of linear functional integrals. Both results are highly relevant outside the field of DM direct detection.
Comments:
73 pages, 11 figures, 1 table, 5 appendices, 659716 wavelets. Updated to match journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2310.01483 [pdf]
PRD(2025)·11 citations
09
[Submitted on 2 Oct 2023] (cross-list from hep-ph)
Flavor Fragmentation Function Factorization
Andrew J. Larkoski🇺🇸 · Duff Neill🇺🇸
A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing along the direction of the Winner-Take-All axis of a jet which is soft safe to all orders, but not collinear safe. Here, we exploit the lack of collinear safety and propose a factorization theorem of perturbative flavor fragmentation functions that resum collinear divergences and describe the evolution of flavor from the short distance of jet production to the long distance at which hadronization occurs. Collinear flavor evolution is governed by a small modification of the DGLAP equations. We present a detailed all-orders analysis and identify exact relations that must hold amongst the various anomalous dimensions by probability conservation and the existence of fixed points of the renormalization group flow. We explicitly validate the factorization theorem at one-loop order, and demonstrate its consistency at two loops in particular flavor channels. Starting at two-loops, constraints on phase space imposed by flavor measurements potentially allow for non-trivial soft contributions, but we demonstrate that they are scaleless and so explicitly vanish, ensuring that soft particles are summed inclusively and all divergences are exclusively collinear in nature. This factorization theorem opens the door to precision calculations with identified flavor in the infrared.
Comments:
38 pages + appendices, 1 figure; v2: JHEP version, some minor expansions of explanations
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2310.01486 [pdf]
JHEP(2024)·4 citations
10
[Submitted on 2 Oct 2023] (cross-list from hep-ph)
Probing the Short-Distance Structure of the Quark-Gluon Plasma with Energy Correlators
Zhong Yang🇨🇳 · Yayun He🇨🇳 · Ian Moult🇺🇸 · Xin-Nian Wang🇨🇳
Energy-energy-correlators (EEC's) are a promising observable to study the dynamics of jet evolution in the quark-gluon plasma (QGP) through its imprint on angular scales in the energy flux of final-state particles. We carry out the first complete calculation of EEC's using realistic simulations of high-energy heavy-ion collisions, and dissect the different dynamics underlying the final distribution through analyses of jet propagation in a uniform medium. The EEC's of $γ$ -jets in heavy-ion collisions are found to be enhanced by the medium response from elastic scatterings instead of induced gluon radiation at large angles. In the meantime, EEC's are suppressed at small angles due to energy loss and transverse momentum broadening of jet shower partons. These modifications are further shown to be sensitive to the angular scale of the in-medium interaction, as characterized by the Debye screening mass. Experimental verification and measurement of such modifications will shed light on this scale, and the short-distance structure of the QGP in heavy-ion collisions.
Comments:
6 pages in ReVTex with 5 figures, final version published in PRL
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2310.01500 [pdf]
PRL(2024)·109 citations
11
[Submitted on 2 Oct 2023] (cross-list from astro-ph.HE)
Indication of Sharp and Strong Phase-Transitions from NICER Observations
Zidu Lin🇺🇸 · Andrew Steiner🇺🇸
In this letter, we present a new, weakly model-dependent, test for ``standard" equations of state (EoS) models that disfavor sharp and strong phase-transitions, by using neutron star mass and radius observations. We show the radii of two neutron stars observed by NICER (PSR J0740+6620 and PSR 0030+0451) are correlated if these two neutron stars are built upon standard EoS models. The radii of neutron stars with different masses are sensitive to the pressures at different densities, and the pressures at different densities are strongly correlated in standard EoS models. We further show that the correlation of the neutron star radii can be significantly weakened, when additional degrees of freedom concerning the first-order phase transitions are added into the EoSs. We propose a new quantity, $D_{L}$ , which measures the extent to which the linear correlation of the radii of two neutron stars is weakened. Our method gives a $48%$ identification probability (with a $5%$ false alarm rate) of finding beyond standard EoS models in NICER observations. Future observations with higher measurement accuracy can confirm or rule out this identification. Our method is generalizable to any pair of neutron star masses and can be employed with other sets of observations in the future.
Comments:
Comments are welcome, accepted by Apj Letters
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2310.01619 [pdf]
ApJL(2024)·9 citations
12
[Submitted on 3 Oct 2023] (cross-list from hep-th)
A new perspective on thermal transition in QCD
Masanori Hanada🇬🇧 · Hiroki Ohata🇯🇵 · Hidehiko Shimada🇯🇵 · Hiromasa Watanabe🇯🇵
Motivated by the picture of partial deconfinement developed in recent years for large- $N$ gauge theories, we propose a new way of analyzing and understanding thermal phase transition in QCD. We find nontrivial support for our proposal by analyzing the WHOT-QCD collaboration's lattice configurations for SU(3) QCD in $3 + 1$ spacetime dimensions with up, down, and strange quarks. We find that the Polyakov line (the holonomy matrix around a thermal time circle) is governed by the Haar-random distribution at low temperatures. The deviation from the Haar-random distribution at higher temperatures can be measured via the character expansion, or equivalently, via the expectation values of the Polyakov loop defined by the various nontrivial representations of SU(3). We find that the Polyakov loop corresponding to the fundamental representation and loops in the higher representation condense at different temperatures. This suggests that there are (at least) three phases, one intermediate phase existing in between the completely-confined and the completely-deconfined phases. Our identification of the intermediate phase is supported also by the condensation of instantons: by studying the instanton numbers of the WHOT-QCD configurations, we find that the instanton condensation occurs for temperature regimes corresponding to what we identify as the completely-confined and intermediate phases, whereas the instantons do not condense in the completely-deconfined phase. Our characterization of confinement based on the Haar-randomness explains why the Polyakov loop is a good observable to distinguish the confinement and the deconfinement phases in QCD despite the absence of the $Z_{3}$ center symmetry.
Comments:
v3. 18 pages, 5 figures, 1 table, final version published in PTEP
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2310.01940 [pdf]
PTEP(2024)·19 citations
13
[Submitted on 3 Oct 2023] (cross-list from hep-ph)
Properties of the $T_{cc} (3875)^{+}$ and the $T_{c ˉ c ˉ} (3875)^{-}$ states in nuclear matter
Victor Montesinos🇪🇸 · Miguel Albaladejo🇪🇸 · Juan Nieves🇪🇸 · Laura Tolos🇪🇸
Since its first detection, the interesting properties of the $T_{cc} (3875)^{+}$ have made it to be one of the most prominent tetraquark-like states up to date. In this work we present a joint analysis of the $T_{cc}^{+}$ and its charge-conjugated partner in a dense nuclear medium. We start by considering both states as purely isoscalar $D^{*} D$ and $D^{*} D$ $S$ -wave bound states, respectively. We use previous results for the in-medium $D$ , $D$ , $D^{*}$ and $D^{*}$ spectral functions to determine the modified two-meson amplitudes. We find important changes in the in-medium mass and width of both tetraquark-like resonances, which become more visible when increasing the nuclear density and molecular probabilities. The experimental confirmation of the found distinctive patterns will support the existence of molecular components in the $T_{cc}^{+}$ and $T_{c ˉ c ˉ}^{-}$ wave functions.
Comments:
4 pages, 1 figure, contribution to MESON2023 conference
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2310.02057 [pdf]
EPJ Web Conf.(2024)·1 citation
14
[Submitted on 3 Oct 2023] (cross-list from hep-ph)
Stability of Initial Glasma Fields
Sylwia Bazak🇵🇱 · Stanislaw Mrowczynski🇵🇱
A system of gluon fields produced in the earliest phase of relativistic heavy-ion collisions, which is called `glasma', can be described in terms of classical fields. Initially there are chromoelectric and chromomagnetic fields along the collision axis. A linear stability analysis of these fields is performed, assuming that the fields are space-time uniform and using the SU(2) gauge group. We apply Milne coordinates and the gauge condition which are usually used in studies of glasma. The chromoelectric field is in the Abelian configuration with the corresponding potential linearly depending on coordinates but the chromomagnetic field is in the nonAbelian configuration generated by the potential of non-commuting components. The chromomagnetic field is found to be unstable and the growth rate of the unstable mode is derived. Our findings are critically debated and confronted with the numerical simulations by Romatschke and Venugopalan who found that the evolving glasma is unstable due to the Weibel instability well-known in electromagnetic plasma.
Comments:
19 pages, no figures, to appear in Phys. Rev. C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2310.02205 [pdf]
PRC(2024)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE