#### 1. Introduction

Spin correlation parameter A
*c* [1,2,3]. We propose to measure the beam and target analyzing power and the initial state spin-spin correlation parameter in proton-proton elastic scattering at -t from 0.075 to 0.6 (GeV/*c*)

The results of this experiment can be described by a set of spin parameters, which are related to the pure-initial-spin state differential elastic cross sections by the formula:

where P

where N(ij) is the number of events normalized to the incident proton flux with the beam's (i) and target's (j) spin direction up (
*c* in the diffractive kinematic region.

#### 2. Existing experimental data of the A
N
and A
N N
in proton-proton elastic scattering

A

Measured value of A
*c* is equals to (2.3
*c* [1,2,3] in laboratory system (see Figure 2). The solid line presents the fit to experimental data with the function A
*c.* The expected value for A
*c* is (2.2

#### 3. Beam characteristics and beam polarization measurement

The polarized proton and antiproton beams are described in detail in Ref. [8]. We plan to do these measurements using the 45 Gev/*c* polarized proton beam with the narrow momentum width
*x*)
*y*) = 11

The transvers polarization dependence on the beam-ray position along the vertical axis in the intermediate focus is presented in Figure 3. It can be described by the function

#### 4. Experimental setup

The design of the experimental setup is presented in Figure 4. The main detectors to be used are the trigger scintillator counters (S1-S8) and hodoscopes (H1-H8).

The parameters for all hodoscopes are presented in table 1. The hodoscopes are constructed in such a manner that each scintillator strip overlaps its two adjacent neighbors by one-third of the width. This kind of overlapping arrangement provides twice as many of the spatial segments for the same number of channels of encoding electronics as for the edge-butted array. It also eliminated the loss of tracking efficiency by eliminating the inter-segment gaps.

In order to suppress inelastic events, a special fast trigger will be organized on the base of coincidences between scattered and recoil protons in forward (H3-H4) and backward ((H5-H8) detectors. It worth mentioning, that elastic scattering measurements can be carried out simultaneously with the inclusive double-spin studies, using the main detectors of SPASCHARM experiment.

##### Table 1

#### 5. Beam time estimation

Numerical calculations for the number of elastic scattering events has been done for the worst case scenario with the maximum value of |t|= 0.6 (GeV/*c*)
*c*)

An event rate is defined as n=L
*c*)
*c*)

#### 6. Summary

We proposed the experiment which allows to measure simultaneously three spin observables in elastic pp scattering at 45GeV/*c* in the |*t|* interval of 0.07
*c*)

10 days are required for measuring the t-dependence of A
*t|*.

The momentum dependence of these parameters can be studied in the wider momentum range from 15- to 45 GeV/*c*.

The work on estimations of the possibility to carry out the similar measurements with the polarized-antiproton beam is in progress.

This work has been supported in part by the RFBR Grant No. 16-02-00667 and by the Competitiveness Programme of National Research Nuclear University MEPhI.